Flower Germplasm Resource and Genetic Breeding

A special issue of Plants (ISSN 2223-7747). This special issue belongs to the section "Horticultural Science and Ornamental Plants".

Deadline for manuscript submissions: closed (30 January 2024) | Viewed by 30765

Special Issue Editors


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Guest Editor
Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, School of Landscape Architecture, Beijing Forestry University, Beijing 100083, China.
Interests: germplasm resource; molecular breeding; genetic regulation
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Guest Editor
College of Forestry, Hainan University, Hainan, China
Interests: genomics; bioinformatics
State Forestry and Grassland Administration Key Laboratory of Silviculture in Downstream Areas of the Yellow River, College of Forestry, Shandong Agricultural University, Tai'an, China
Interests: genomics; bioinformatics

Special Issue Information

Dear Colleagues,

In the past several decades, great advances have been made in horticulture germplasm research at both population and individual levels. Especially, these advances have been achieved along with the availability of new techniques and the genome sequences of flower plants. More specific research is necessary to enhance the basic and applied research on flower genetic resources. This Special Issue of Plants will cover various aspects of flower germplasm studies, as follows:

  1. Germplasm collection and genetic diversity. These papers should focus on the collection, preservation, and utilization of flower germplasm, as well as the evaluation and broadening of genetic diversity.
  2. Elite germplasm mining with ideal target traits. These papers should focus on the development of QTL mapping approaches and their application to the characterization of the genetic architecture of plant traits by genetic linkage mapping and/or genome-wide association study. Papers on mapping plant growth traits using functional mapping are particularly welcomed.
  3. New techniques and data reanalysis in germplasm enhancement. These papers should focus on issues that are broadly relevant to the genetics of plant traits. Given the availability of a large number of genomes, transcriptomes, proteomes, and metabolomes across plants, we are interested in submissions that take a holistic approach to survey the data from a new perspective/angle, and/or those which analyze the data using new tools.

Prof. Dr. Lidan Sun
Dr. Shangqian Xie
Dr. Zongda Xu
Guest Editors

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Keywords

  • germplasm resource
  • molecular breeding
  • genetic regulation

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Published Papers (19 papers)

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15 pages, 3865 KiB  
Article
Obtaining and Characterization of an Interspecific Hybrid between Lilium callosum and ‘Snow Queen’ and Evaluation of the Botrytis Stress Response
by Yongyao Fu, Shulin Lu, Chengchen Liu, Chaojun Ding, Xiaoyu Wang, Xinrong Li, Sijia Jiang and Liping Yang
Plants 2024, 13(10), 1376; https://doi.org/10.3390/plants13101376 - 15 May 2024
Viewed by 981
Abstract
To cultivate excellent lily germplasms, an interspecific hybrid (LC×SQ-01) was successfully obtained by using a cut-style pollination method in which the rare wild lily Lilium callosum was used as the female parent and the cut flower L. longiflorum ‘Snow Queen’ was used as [...] Read more.
To cultivate excellent lily germplasms, an interspecific hybrid (LC×SQ-01) was successfully obtained by using a cut-style pollination method in which the rare wild lily Lilium callosum was used as the female parent and the cut flower L. longiflorum ‘Snow Queen’ was used as the male parent. The morphological features of LC×SQ-01 included height, leaf length, and width, which were observed to be between those of the parents in the tissue-cultured seedlings. The height and leaf length of LC×SQ-01 were more similar to those of the male parent, and the width was between the widths of the parents for field-generated plants. The epidermal cell length and the guard cell and stoma sizes were between those of both parents in tissue-cultured and field-generated plants. In addition, the shapes of the epidermal cells and anticlinal wall in LC×SQ-01 were more analogous to those in the male parent, while the stoma morphology was different from that of both parents. Fourteen pairs of polymorphic SSR primers were identified in both parents, and the validity of LC×SQ-01 was demonstrated by PCR amplification using five pairs of SSR primers. Flow cytometry and root tip squashing assays revealed that LC×SQ-01 was a diploid plant, similar to its parents. Furthermore, the LC×SQ-01 hybrid was more resistant to B. cinerea than its parents, and it also showed much greater peroxidase (POD) and catalase (CAT) activity than the parents. These results lay a foundation for breeding a new high-resistance and ornamental lily variety. Full article
(This article belongs to the Special Issue Flower Germplasm Resource and Genetic Breeding)
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21 pages, 4882 KiB  
Article
WRKY22 Transcription Factor from Iris laevigata Regulates Flowering Time and Resistance to Salt and Drought
by Lijuan Fan, Zhaoqian Niu, Gongfa Shi, Ziyi Song, Qianqian Yang, Sheng Zhou and Ling Wang
Plants 2024, 13(9), 1191; https://doi.org/10.3390/plants13091191 - 25 Apr 2024
Cited by 2 | Viewed by 1021
Abstract
Iris laevigata Fisch. is an excellent ornamental plant in cold regions due to its unique ornamental ability and strong cold resistance. However, the flowering period of the population is only about 20 days, greatly limiting its potential uses in landscaping and the cutting [...] Read more.
Iris laevigata Fisch. is an excellent ornamental plant in cold regions due to its unique ornamental ability and strong cold resistance. However, the flowering period of the population is only about 20 days, greatly limiting its potential uses in landscaping and the cutting flower industry. In addition, I. laevigata is often challenged with various abiotic stresses including high salinity and drought in its native habitats. Thus, breeding novel cultivars with delayed flowering time and higher resistance to abiotic stress is of high importance. In this study, we utilized sequencing data from the I. laevigata transcriptome to identify WRKYs and characterized IlWRKY22, a key transcription factor that modulates flowering time and abiotic stress responses. IlWRKY22 is induced by salt and drought stress. We cloned IlWRKY22 and found that it is a Group IIe WRKY localized in the nucleus. Overexpressing IlWRKY22 in Arabidopsis thaliana (L.) Heynh. and Nicotiana tabacum L. resulted in a delayed flowering time in the transgenic plants. We created transgenic N. tabacum overexpressing IlWRKY22, which showed significantly improved resistance to both salt and drought compared to the control plants. Thus, our study revealed a unique dual function of IlWRKY22, an excellent candidate gene for breeding novel Iris cultivars of desirable traits. Full article
(This article belongs to the Special Issue Flower Germplasm Resource and Genetic Breeding)
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15 pages, 4400 KiB  
Article
Integration of Metabolomic and Transcriptomic Analyses Reveals the Molecular Mechanisms of Flower Color Formation in Prunus mume
by Ruyi Wang, Xin Yang, Tao Wang, Baohui Li, Ping Li and Qin Zhang
Plants 2024, 13(8), 1077; https://doi.org/10.3390/plants13081077 - 11 Apr 2024
Viewed by 1171
Abstract
Flower color is an important trait that affects the economic value of Prunus mume, a famous ornamental plant in the Rosaceae family. P. mume with purple–red flowers is uniquely charming and highly favored in landscape applications. However, little is known about its [...] Read more.
Flower color is an important trait that affects the economic value of Prunus mume, a famous ornamental plant in the Rosaceae family. P. mume with purple–red flowers is uniquely charming and highly favored in landscape applications. However, little is known about its flower coloring mechanism, which stands as a critical obstacle on the path to innovative breeding for P. mume flower color. In this study, transcriptomic and targeted metabolomic analyses of purple–red P. mume and white P. mume were performed to elucidate the mechanism of flower color formation. In addition, the expression patterns of key genes were analyzed using an RT-qPCR experiment. The results showed that the differential metabolites were significantly enriched in the flavonoid synthesis pathway. A total of 14 anthocyanins emerged as the pivotal metabolites responsible for the differences in flower color between the two P. mume cultivars, comprising seven cyanidin derivatives, five pelargonium derivatives, and two paeoniflorin derivatives. Moreover, the results clarified that the metabolic pathway determining flower color in purple–red P. mume encompasses two distinct branches: cyanidin and pelargonidin, excluding the delphinidin branch. Additionally, through the integrated analysis of transcriptomic and metabolomic data, we identified 18 key genes responsible for anthocyanin regulation, thereby constructing the gene regulatory network for P. mume anthocyanin synthesis. Among them, ten genes (PmCHI, PmGT2, PmGT5, PmGST3, PmMYB17, PmMYB22, PmMYB23, PmbHLH4, PmbHLH10, and PmbHLH20) related to anthocyanin synthesis were significantly positively correlated with anthocyanin contents, indicating that they may be the key contributors to anthocyanin accumulation. Our investigation contributes a novel perspective to understanding the mechanisms responsible for flower color formation in P. mume. The findings of this study introduce novel strategies for molecular design breeding aimed at manipulating flower color in P. mume. Full article
(This article belongs to the Special Issue Flower Germplasm Resource and Genetic Breeding)
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25 pages, 12951 KiB  
Article
MADS-Box Family Genes in Lagerstroemia indica and Their Involvement in Flower Development
by Zhongquan Qiao, Fuyuan Deng, Huijie Zeng, Xuelu Li, Liushu Lu, Yuxing Lei, Lu Li, Yi Chen and Jianjun Chen
Plants 2024, 13(5), 709; https://doi.org/10.3390/plants13050709 - 1 Mar 2024
Cited by 1 | Viewed by 1454
Abstract
MADS-box is a key transcription factor regulating the transition to flowering and flower development. Lagerstroemia indica ‘Xiang Yun’ is a new cultivar of crape myrtle characterized by its non-fruiting nature. To study the molecular mechanism underlying the non-fruiting characteristics of ‘Xiang Yun’, 82 [...] Read more.
MADS-box is a key transcription factor regulating the transition to flowering and flower development. Lagerstroemia indica ‘Xiang Yun’ is a new cultivar of crape myrtle characterized by its non-fruiting nature. To study the molecular mechanism underlying the non-fruiting characteristics of ‘Xiang Yun’, 82 MADS-box genes were identified from the genome of L. indica. The physicochemical properties of these genes were examined using bioinformatics methods, and their expression as well as endogenous hormone levels at various stages of flower development were analyzed. The results showed that LiMADS genes were primarily classified into two types: type I and type II, with the majority being type II that contained an abundance of cis-acting elements in their promoters. By screening nine core proteins by predicted protein interactions and performing qRT-PCR analysis as well as in combination with transcriptome data, we found that the expression levels of most MADS genes involved in flower development were significantly lower in ‘Xiang Yun’ than in the wild type ‘Hong Ye’. Hormonal analysis indicated that ‘Xiang Yun’ had higher levels of iP, IPR, TZR, and zeatin during its early stages of flower development than ‘Hong Ye’, whereas the MeJA content was substantially lower at the late stage of flower development of ‘Hong Ye’. Finally, correlation analysis showed that JA, IAA, SA, and TZR were positively correlated with the expression levels of most type II genes. Based on these analyses, a working model for the non-fruiting ‘Xiang Yun’ was proposed. During the course of flower development, plant hormone response pathways may affect the expression of MADS genes, resulting in their low expression in flower development, which led to the abnormal development of the stamen and embryo sac and ultimately affected the fruiting process of ‘Xiang Yun’. Full article
(This article belongs to the Special Issue Flower Germplasm Resource and Genetic Breeding)
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15 pages, 3344 KiB  
Article
Genetic Analyses of Flower Main Traits from Two Pitayas and Their Progenies: A Cactus Plant
by Tiantian Zhang, Kangmin Xing, Jiayi Chen, Irfan Ali Sabir, Kamran Shah, Jiaxuan Chen, Zhike Zhang, Jietang Zhao, Guibing Hu and Yonghua Qin
Plants 2024, 13(5), 699; https://doi.org/10.3390/plants13050699 - 29 Feb 2024
Viewed by 1137
Abstract
Elucidation of the genetic foundation governing crucial traits in pitaya flowers is imperative for enhancing both the ornamental and economic values. In this study, the dynamic variation in flower genetics, segregation variation patterns, and a mixed inheritance model of the major and multigene [...] Read more.
Elucidation of the genetic foundation governing crucial traits in pitaya flowers is imperative for enhancing both the ornamental and economic values. In this study, the dynamic variation in flower genetics, segregation variation patterns, and a mixed inheritance model of the major and multigene flower traits of ‘Dahong’ and ‘Honghuaqinglong’ pitayas and their progenies were explored. The results showed that the main traits of flowers exhibited varying degrees of variation among the reciprocal F1 hybrids, with the data exhibiting the characteristics of quantitative traits. The betalain content, petal number, and stigma number exhibited values below the median values of the parents, suggesting a genetic inclination towards lower values. Perianth width, calyx tube width, petal number, and stigma number had the same genetic effects and significant correlation. Stigma-related traits had a clear maternal inheritance tendency. The heritability of flower length, stigma relative to anther distance, and petal betalain content was governed by two pairs of additive-dominant major genes. Perianth width, calyx tube width, petal number, and stigma number all conformed to the model of two pairs of equal-additive-dominant major genes. This study provides valuable information for parental selection, cross-breeding, and the enhancement of pitaya varieties to meet market preferences and environmental conditions. Full article
(This article belongs to the Special Issue Flower Germplasm Resource and Genetic Breeding)
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13 pages, 1453 KiB  
Article
Assessing Amounts of Genetic Variability in Key Horticultural Traits Underlying Core Korean Breeding Lines of Cut Chrysanthemums
by Seung-Young Kim, Haying-Youl Lee, Chanrim Park, Daegwan Kim, Jung-Bun Kim, So-Hyun Kim, Kyeong-Jin Jeong, Ha-Seung Pak, Jae-A Jung and Tae-Sung Kim
Plants 2024, 13(5), 577; https://doi.org/10.3390/plants13050577 - 20 Feb 2024
Viewed by 1403
Abstract
The cut chrysanthemum holds one of the most substantial segments of the global floriculture market, particularly in Korea. We conducted a detailed assessment of the genetic structures across the cut chrysanthemum breeding lines in Korea. Using standard and spray chrysanthemum breeding lines from [...] Read more.
The cut chrysanthemum holds one of the most substantial segments of the global floriculture market, particularly in Korea. We conducted a detailed assessment of the genetic structures across the cut chrysanthemum breeding lines in Korea. Using standard and spray chrysanthemum breeding lines from leading Korean research institutes, we first compared the variability of 12 horticultural traits, revealing a wide range of variation for most traits. We found that the overall flower diameter (OFD) and ray floret length (RFL) showed a solid positive relationship, regardless of the type. From a multivariate approach, OFD, RFL, and ray floret width (RFW) show consistently high association. Genotypic and phenotypic coefficients of variation analyses further indicated the significant genetic control over most traits. However, certain traits, like the volume of flowers (VF) in standard types, are more influenced by environments. Lastly, our analysis demonstrated substantial variability in broad-sense heritability (H); plant height (PH) consistently showed high H in both types. But the number of side branches (NOSB) and VF exhibited inconsistent H scores. These findings highlight the need for type-specific breeding strategies and modulating environmental management to optimize the trait expressions depending on the H scores, which offers significant implications for future breeding strategies. Full article
(This article belongs to the Special Issue Flower Germplasm Resource and Genetic Breeding)
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16 pages, 7529 KiB  
Article
Genome-Wide Identification of bZIP Transcription Factors in Cymbidium ensifolium and Analysis of Their Expression under Low-Temperature Stress
by Huiping Lai, Mengyao Wang, Lu Yan, Caiyun Feng, Yang Tian, Xinyue Tian, Donghui Peng, Siren Lan, Yanping Zhang and Ye Ai
Plants 2024, 13(2), 219; https://doi.org/10.3390/plants13020219 - 12 Jan 2024
Cited by 3 | Viewed by 1557
Abstract
The basic leucine zipper (bZIP) transcription factors constitute the most widely distributed and conserved eukaryotic family. They play crucial roles in plant growth, development, and responses to both biotic and abiotic stresses, exerting strong regulatory control over the expression of downstream genes. In [...] Read more.
The basic leucine zipper (bZIP) transcription factors constitute the most widely distributed and conserved eukaryotic family. They play crucial roles in plant growth, development, and responses to both biotic and abiotic stresses, exerting strong regulatory control over the expression of downstream genes. In this study, a genome-wide characterization of the CebZIP transcription factor family was conducted using bioinformatic analysis. Various aspects, including physicochemical properties, phylogenetics, conserved structural domains, gene structures, chromosomal distribution, gene covariance relationships, promoter cis-acting elements, and gene expression patterns, were thoroughly analyzed. A total of 70 CebZIP genes were identified from the C. ensifolium genome, and they were randomly distributed across 18 chromosomes. The phylogenetic tree clustered them into 11 subfamilies, each exhibiting complex gene structures and conserved motifs arranged in a specific order. Nineteen pairs of duplicated genes were identified among the 70 CebZIP genes, with sixteen pairs affected by purifying selection. Cis-acting elements analysis revealed a plethora of regulatory elements associated with stress response, plant hormones, and plant growth and development. Transcriptome and qRT-PCR results demonstrated that the expression of CebZIP genes was universally up-regulated under low temperature conditions. However, the expression patterns varied among different members. This study provides theoretical references for identifying key bZIP genes in C. ensifolium that confer resistance to low-temperature stress, and lays the groundwork for further research into their broader biological functions. Full article
(This article belongs to the Special Issue Flower Germplasm Resource and Genetic Breeding)
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28 pages, 4654 KiB  
Article
Hydrangea arborescens ‘Annabelle’ Flower Formation and Flowering in the Current Year
by Xiaoxu Huang, Tong Lyu, Zheng Li and Yingmin Lyu
Plants 2023, 12(24), 4103; https://doi.org/10.3390/plants12244103 - 7 Dec 2023
Viewed by 1827
Abstract
The perennial woody plant Hydrangea arborescens ‘Annabelle’ is of great research value due to its unique mechanism of flower development that occurs in the current year, resulting in decorative flowers that can be enjoyed for a relatively long period of time. However, the [...] Read more.
The perennial woody plant Hydrangea arborescens ‘Annabelle’ is of great research value due to its unique mechanism of flower development that occurs in the current year, resulting in decorative flowers that can be enjoyed for a relatively long period of time. However, the mechanisms underlying the regulation of current-year flower development in H. arborescens ‘Annabelle’ are still not fully understood. In this study, we conducted an associated analysis to explore the core regulating network in H. arborescens ‘Annabelle’ by combining phenological observations, physiological assays, and transcriptome comparisons across seven flower developmental stages. Through this analysis, we constructed a gene co-expression network (GCN) based on the highest reciprocal rank (HRR), using 509 differentially expressed genes (DEGs) identified from seven flowering-related pathways, as well as the biosynthesis of eight flowering-related phytohormones and signal transduction in the transcriptomic analysis. According to the analysis of the GCN, we identified 14 key genes with the highest functional connectivity that played critical roles in specific development stages. We confirmed that 135 transcription factors (AP2/ERF, bHLH, CO-like, GRAS, MIKC, SBP, WRKY) were highly co-expressed with the 14 key genes, indicating their close associations with the development of current-year flowers. We further proposed a hypothetical model of a gene regulatory network for the development of the whole flower. This model suggested that the photoperiod, aging, and gibberellin pathways, along with the phytohormones abscisic acid (ABA), gibberellin (GA), brassinosteroid (BR), and jasmonic acid (JA), work synergistically to promote the floral transition. Additionally, auxin, GA, JA, ABA, and salicylic acid (SA) regulated the blooming process by involving the circadian clock. Cytokinin (CTK), ethylene (ETH), and SA were key regulators that affected flower senescence. Additionally, several floral integrators (HaLFY, HaSOC1-2, HaAP1, HaFULL, HaAGL24, HaFLC, etc.) were dominant contributors to the development of H. arborescens flowers. Overall, this research provides a comprehensive understanding of the dynamic mechanism underlying the entire process of current-year flower development, thereby offering valuable insights for further studies on the flower development of H. arborescens ‘Annabelle’. Full article
(This article belongs to the Special Issue Flower Germplasm Resource and Genetic Breeding)
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19 pages, 8816 KiB  
Article
Disruption of the Contents of Endogenous Hormones Cause Pollen Development Obstruction and Abortion in Male-Sterile Hybrid Lily Populations
by Wenjie Jia, Xiang Li, Rui Wang, Qing Duan, Junna He, Junping Gao and Jihua Wang
Plants 2023, 12(22), 3804; https://doi.org/10.3390/plants12223804 - 8 Nov 2023
Cited by 5 | Viewed by 1636
Abstract
Lilies are well−known flowers with large anthers and a high quantity of pollen that easily contaminates clothing and tepals. The anthers need to be artificially removed, leading to production problems. Cultivating male−sterile or pollen−free lilies could solve these problems. The key period of [...] Read more.
Lilies are well−known flowers with large anthers and a high quantity of pollen that easily contaminates clothing and tepals. The anthers need to be artificially removed, leading to production problems. Cultivating male−sterile or pollen−free lilies could solve these problems. The key period of male sterility in a specific male−sterile hybrid lily population was determined through cytological observation. The contents of hormones, soluble sugar, soluble protein, and proline were determined by high−performance liquid chromatography, tandem mass spectrometry and colorimetry. Transcriptome sequencing was used to identify the genes with altered expression. The key period of male sterility was determined to be the microspore mother and tetrad stages. The hormone contents were abnormal in the sterile line compared with the fertile line. The indole−3−acetic acid (IAA) content was higher in the sterile line than in the fertile line at all stages, while the gibberellic acid 4 (GA4) content showed the opposite result. Abscisic acid (ABA) accumulated in the sterile line in both the microspore mother and tetrad stages, and the zeatin riboside (ZR) content in the sterile line increased at the microspore mother stage but decreased at the tetrad stage. The contents of soluble sugar, soluble protein and proline were higher in the fertile line than in the sterile line. Genes involved in auxin and ABA synthesis and signalling pathways were highly expressed in the male−sterile line. Our data suggested that abnormal contents of hormones in the microspore mother and tetrad stages resulted in pollen abortion in a male−sterile hybrid lily population, which indicated that the hormone balance in specific stages plays critical functions in pollen development in lilies. Full article
(This article belongs to the Special Issue Flower Germplasm Resource and Genetic Breeding)
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23 pages, 8565 KiB  
Article
Integrative Analysis of Metabolome and Transcriptome Revealed Lutein Metabolism Contributed to Yellow Flower Formation in Prunus mume
by Aiqin Ding, Fei Bao, Xi Yuan, Jia Wang, Tangren Cheng and Qixiang Zhang
Plants 2023, 12(18), 3333; https://doi.org/10.3390/plants12183333 - 21 Sep 2023
Viewed by 1665
Abstract
Prunus mume is a famous ornamental woody tree with colorful flowers. P. mume with yellow flowers is one of the most precious varieties. Regretfully, metabolites and regulatory mechanisms of yellow flowers in P. mume are still unclear. This hinders innovation of flower color [...] Read more.
Prunus mume is a famous ornamental woody tree with colorful flowers. P. mume with yellow flowers is one of the most precious varieties. Regretfully, metabolites and regulatory mechanisms of yellow flowers in P. mume are still unclear. This hinders innovation of flower color breeding in P. mume. To elucidate the metabolic components and molecular mechanisms of yellow flowers, we analyzed transcriptome and metabolome between ‘HJH’ with yellow flowers and ‘ZLE’ with white flowers. Comparing the metabolome of the two varieties, we determined that carotenoids made contributions to the yellow flowers rather than flavonoids. Lutein was the key differential metabolite to cause yellow coloration of ‘HJH’. Transcriptome analysis revealed significant differences in the expression of carotenoid cleavage dioxygenase (CCD) between the two varieties. Specifically, the expression level of PmCCD4 was higher in ‘ZLE’ than that in ‘HJH’. Moreover, we identified six major transcription factors that probably regulated PmCCD4 to affect lutein accumulation. We speculated that carotenoid cleavage genes might be closely related to the yellow flower phenotype in P. mume. Further, the coding sequence of PmCCD4 has been cloned from the ‘HJH’ petals, and bioinformatics analysis revealed that PmCCD4 possessed conserved histidine residues, ensuring its enzymatic activity. PmCCD4 was closely related to PpCCD4, with a homology of 98.16%. Instantaneous transformation analysis in petal protoplasts of P. mume revealed PmCCD4 localization in the plastid. The overexpression of PmCCD4 significantly reduced the carotenoid content in tobacco plants, especially the lutein content, indicating that lutein might be the primary substrate for PmCCD4. We speculated that PmCCD4 might be involved in the cleavage of lutein in plastids, thereby affecting the formation of yellow flowers in P. mume. This work could establish a material and molecular basis of molecular breeding in P. mume for improving the flower color. Full article
(This article belongs to the Special Issue Flower Germplasm Resource and Genetic Breeding)
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16 pages, 13303 KiB  
Article
Genome-Wide Identification of the RR Gene Family and Its Expression Analysis in Response to TDZ Induction in Rhododendron delavayi
by Lvchun Peng, Xuejiao Li, Yan Gao, Weijia Xie, Lu Zhang, Jie Song, Shifeng Li and Zhengxiong Zhao
Plants 2023, 12(18), 3250; https://doi.org/10.3390/plants12183250 - 13 Sep 2023
Cited by 2 | Viewed by 1278
Abstract
The cytokinin response regulator (RR) gene is essential for cytokinin signal transduction, which plays a crucial role in plant growth and development. Here, we applied bioinformatics to Rhododendron delavayi’s genome to identify its RR gene family and systematically analyzed their gene characteristics, [...] Read more.
The cytokinin response regulator (RR) gene is essential for cytokinin signal transduction, which plays a crucial role in plant growth and development. Here, we applied bioinformatics to Rhododendron delavayi’s genome to identify its RR gene family and systematically analyzed their gene characteristics, phylogenetic evolution, chromosomal localization, collinearity analysis, promoter cis-elements, and expression patterns. Overall, 33 RdRR genes were distinguished and classified into three types. All these genes harbored motif 5 (YEVTTVNSGLEALELLRENKB), the most conserved one, along with the plant-conserved domain (REC domain), and could be mapped to 10 chromosomes with four gene pairs of segmental replication events but no tandem replication events; 13 RdRR genes showed collinearity with Arabidopsis thaliana genes. Promoter analysis revealed multiple hormone-related cis-elements in the RR genes. After a TDZ (thidiazuron) treatment, 13 genes had higher expression levels than the control, whose magnitude of change depended on the developmental stage of leaves’ adventitious buds. The expression levels of RdRR14, RdRR17, RdRR20, and RdRR24 agreed with the average number of adventitious buds post-TDZ treatment. We speculate that these four genes could figure prominently in bud regeneration from R. delavayi leaves in vitro. This study provides detailed knowledge of RdRRs for research on cytokinin signaling and RdRR functioning in R. delavayi. Full article
(This article belongs to the Special Issue Flower Germplasm Resource and Genetic Breeding)
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17 pages, 3768 KiB  
Article
Genome-Wide Identified MADS-Box Genes in Prunus campanulata ‘Plena’ and Theirs Roles in Double-Flower Development
by Chaoren Nie, Xiaoguo Xu, Xiaoqin Zhang, Wensheng Xia, Hongbing Sun, Na Li, Zhaoquan Ding and Yingmin Lv
Plants 2023, 12(17), 3171; https://doi.org/10.3390/plants12173171 - 4 Sep 2023
Cited by 4 | Viewed by 1535
Abstract
The MADS-box gene family plays key roles in flower induction, floral initiation, and floral morphogenesis in flowering plants. To understand their functions in the double-flower formation of Prunus campanulata ‘Plena’ (hereafter referred to as PCP), which is an excellent flowering cherry cultivar, we [...] Read more.
The MADS-box gene family plays key roles in flower induction, floral initiation, and floral morphogenesis in flowering plants. To understand their functions in the double-flower formation of Prunus campanulata ‘Plena’ (hereafter referred to as PCP), which is an excellent flowering cherry cultivar, we performed genome-wide identification of the MADS-box gene family. In this study, 71 MADS-box genes were identified and grouped into the Mα, Mβ, Mγ and MIKC subfamilies according to their structures and phylogenetic relationships. All 71 MADS-box genes were located on eight chromosomes of PCP. Analysis of the cis-acting elements in the promoter region of MADS-box genes indicated that they were associated mainly with auxin, abscisic acid, gibberellin, MeJA (methyl jasmonate), and salicylic acid responsiveness, which may be involved in floral development and differentiation. By observing the floral organ phenotype, we found that the double-flower phenotype of PCP originated from petaloid stamens. The analysis of MIKC-type MADS-box genes in PCP vegetative and floral organs by qRT–PCR revealed six upregulated genes involved in petal development and three downregulated genes participating in stamen identity. Comparative analysis of petaloid stamens and normal stamens also indicated that the expression level of the AG gene (PcMADS40) was significantly reduced. Thus, we speculated that these upregulated and downregulated genes, especially PcMADS40, may lead to petaloid stamen formation and thus double flowers. This study lays a theoretical foundation for MADS-box gene identification and classification and studying the molecular mechanism underlying double flowers in other ornamental plants. Full article
(This article belongs to the Special Issue Flower Germplasm Resource and Genetic Breeding)
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16 pages, 3148 KiB  
Article
Characterization of Agronomic and Seed Oil Features for Different Cultivars of Tree Peony
by Hao Wang, Shuo Wei, Yinglong He, Xiaohui Wang, Yuying Li, Dongfeng Wei, Zhanying Wang, Lili Guo, Muhammad Shaaban and Xiaogai Hou
Plants 2023, 12(17), 3112; https://doi.org/10.3390/plants12173112 - 30 Aug 2023
Cited by 1 | Viewed by 1299
Abstract
Tree peony is a unique oil plant resource in China, and tree peony seed oil is one of the healthy edible oils with a very promising future. However, the main oil tree peony cultivars promoted in China are Paeonia ostii ‘Fengdan’ and Paeonia [...] Read more.
Tree peony is a unique oil plant resource in China, and tree peony seed oil is one of the healthy edible oils with a very promising future. However, the main oil tree peony cultivars promoted in China are Paeonia ostii ‘Fengdan’ and Paeonia rockii. In order to explore new oil tree peony cultivars, 68 tree peony cultivars were investigated and cultivars with oil potential were selected by cluster analysis and grey relational analysis (GRA) in this study. The results demonstrated that the 68 cultivars varied significantly in terms of agronomic characteristics (p < 0.05), with the coefficient of variation in seed yield per plant reaching a high of 75.36%. The oil content of 46 cultivars was higher than ‘Fengdan’ (20.87 ± 0.26%) and ‘Zibanbai’ (21.24 ± 1.01%), while the alpha-linolenic acids and total unsaturated fatty acid contents of 26 cultivars were higher than ‘Fengdan’ (39.79 ± 1.13% and 88.99 ± 0.47%) and ‘Zibanbai’ (40.51 ± 0.09% and 93.59 ± 0.09%). Finally, three cultivars with better integrated traits were selected by cluster analysis and grey relational analysis (GRA), comprising of ‘Changshoule’, ‘Xianchizhenghui’, and ‘Yupantuojin’. The contents of alpha-linolenic acids and total unsaturated fatty acids in ‘Changshoule’ (47.98 ± 0.17% and 93.60 ± 0.08%), ‘Xianchizhenghui’ (49.44 ± 0.63% and 93.80 ± 0.06%), and ‘Yupantuojin’ (40.46 ± 0.26% and 93.58 ± 0.06%) were higher than that of ‘Fengdan’ (39.79 ± 1.13% and 88.99 ± 0.47%). In general, these cultivars can be used as hybrid parental materials for breeding new excellent oil tree peony cultivars. Full article
(This article belongs to the Special Issue Flower Germplasm Resource and Genetic Breeding)
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21 pages, 6769 KiB  
Article
Insight into the Molecular Mechanism of Flower Color Regulation in Rhododendron latoucheae Franch: A Multi-Omics Approach
by Peng Xiao, Hui Zhang, Qiulin Liao, Ninghua Zhu, Jiaao Chen, Lehan Ma, Minhuan Zhang and Shouyun Shen
Plants 2023, 12(16), 2897; https://doi.org/10.3390/plants12162897 - 8 Aug 2023
Cited by 1 | Viewed by 1795
Abstract
Rhododendron latoucheae Franch. (R. latoucheae) is a valuable woody plant known for its high ornamental value. While purple flowers are a distinct and attractive variant phenotype of R. latoucheae, the underlying mechanism regulating its flower color is still poorly understood. [...] Read more.
Rhododendron latoucheae Franch. (R. latoucheae) is a valuable woody plant known for its high ornamental value. While purple flowers are a distinct and attractive variant phenotype of R. latoucheae, the underlying mechanism regulating its flower color is still poorly understood. To investigate the molecular regulatory mechanism responsible for the variation in flower color, we selected plants with white-pink and purple petals as the object and conducted analyses of metabolites, key genes, and transcription factors associated with flower color. A combined metabolome–transcriptome analysis was performed, and the expression of key genes was subsequently verified through qRT-PCR experiments. The results of our study demonstrated a significant enrichment of differential metabolites in the flavonoid metabolic pathway. Changes in anthocyanin content followed the same trend as the observed flower color variations, specifically showing significant correlations with the contents of malvidin-3-O-glucoside, dihydromyricetin, gallocatechin, and peonidin-3-O-glucoside. Furthermore, we identified three key structural genes (F3GT1, LAR, ANR) and four transcription factors (bHLH130, bHLH41, bHLH123, MYB4) that are potentially associated with the biosynthesis of flavonoid compounds, thereby influencing the appearance of purple flower color in R. latoucheae. Full article
(This article belongs to the Special Issue Flower Germplasm Resource and Genetic Breeding)
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13 pages, 3136 KiB  
Article
Screening of Reference miRNA of Different Early- and Late-Flowering Tree Peony Varieties
by Jiajia Shen, Xiaohui Wang, Yuying Li, Lili Guo and Xiaogai Hou
Plants 2023, 12(14), 2629; https://doi.org/10.3390/plants12142629 - 12 Jul 2023
Cited by 1 | Viewed by 1382
Abstract
miRNA plays an important role in plant growth and development and in response to various stresses. Quantitative real-time PCR (qRT-PCR) technology is often used to detect the expression level of miRNAs and genes by comparing with reference genes. In order to screen out [...] Read more.
miRNA plays an important role in plant growth and development and in response to various stresses. Quantitative real-time PCR (qRT-PCR) technology is often used to detect the expression level of miRNAs and genes by comparing with reference genes. In order to screen out the optimal reference miRNAs in different tree peony varieties, the petals of 42 different early- and late-flowering tree peony varieties were used as experimental materials, and geNorm, NormFinder, Bestkeeper, and RefFinder software were used to evaluate the stability of 16 candidate reference miRNAs. The results showed that the average Ct values of all candidate reference miRNAs were between 15.34 ± 0.29 and 32.64 ± 0.38. The optimal number of reference miRNAs was four, which were PsPC-5p-19095, PsPC-3p-51259, PsmiR159a, and PsPC-3p-6660 in geNorm. The stability of PsPC-3p-6660 was the highest in the analysis results of NormFinder software. Among the analysis results of Bestkeeper software, PsMIR319-p5 has the highest stability. Among the results of comprehensive evaluation and analysis of several software using RefFinder, the candidate reference miRNA with the highest stability was PsPC-3p-6660. When PsPC-3p-6660 was used as the reference miRNA, the expression of PomiR171 and PomiR414 in response to different flowering times of tree peony was relatively stable in 42 tree peony varieties, indicating that PsPC-3p-6660 was stable and reliable. The results of this study provide a reference miRNA for studying the expression changes of miRNA in different tree peony varieties and further exploring the regulatory mechanism of miRNA in different peony varieties. Full article
(This article belongs to the Special Issue Flower Germplasm Resource and Genetic Breeding)
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21 pages, 5879 KiB  
Article
Whole-Genome Identification of Regulatory Function of CDPK Gene Families in Cold Stress Response for Prunus mume and Prunus mume var. Tortuosa
by Runtian Miao, Mingyu Li, Zhenying Wen, Juan Meng, Xu Liu, Dongqing Fan, Wenjuan Lv, Tangren Cheng, Qixiang Zhang and Lidan Sun
Plants 2023, 12(13), 2548; https://doi.org/10.3390/plants12132548 - 4 Jul 2023
Cited by 5 | Viewed by 1540
Abstract
Calcium-dependent protein kinases (CDPK) are known to mediate plant growth and development and respond to various environmental changes. Here, we performed whole-genome identification of CDPK families in cultivated and wild mei (Prunus mume). We identified 14 and 17 CDPK genes in [...] Read more.
Calcium-dependent protein kinases (CDPK) are known to mediate plant growth and development and respond to various environmental changes. Here, we performed whole-genome identification of CDPK families in cultivated and wild mei (Prunus mume). We identified 14 and 17 CDPK genes in P. mume and P. mume var. Tortuosa genomes, respectively. All 270 CPDK proteins were classified into four clade, displaying frequent homologies between these two genomes and those of other Rosaceae species. Exon/intron structure, motif and synteny blocks were conserved between P. mume and P. mume var. Tortuosa. The interaction network revealed all PmCDPK and PmvCDPK proteins is interacted with respiratory burst oxidase homologs (RBOHs) and mitogen-activated protein kinase (MAPK). RNA-seq data analysis of cold experiments show that cis-acting elements in the PmCDPK genes, especially PmCDPK14, are associated with cold hardiness. Our results provide and broad insights into CDPK gene families in mei and their role in modulating cold stress response in plants. Full article
(This article belongs to the Special Issue Flower Germplasm Resource and Genetic Breeding)
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15 pages, 4143 KiB  
Article
Identification of Floral Volatile Components and Expression Analysis of Controlling Gene in Paeonia ostii ‘Fengdan’ under Different Cultivation Conditions
by Huili Ma, Chenjie Zhang, Tongfei Niu, Meida Chen, Lili Guo and Xiaogai Hou
Plants 2023, 12(13), 2453; https://doi.org/10.3390/plants12132453 - 26 Jun 2023
Cited by 4 | Viewed by 1513
Abstract
In order to explore the release rule of floral volatile substances and the diurnal variation of different flower development stages of Paeonia ostii ‘Fengdan’ in potted and ground-planted conditions, dynamic headspace adsorption combined with gas chromatography-mass spectrometry(GC-MS) was used to analyze the dynamic [...] Read more.
In order to explore the release rule of floral volatile substances and the diurnal variation of different flower development stages of Paeonia ostii ‘Fengdan’ in potted and ground-planted conditions, dynamic headspace adsorption combined with gas chromatography-mass spectrometry(GC-MS) was used to analyze the dynamic changes in floral volatile components and contents. Quantitative real-time PCR (qRT-PCR) was used to analyze changes in flower fragrance-regulating genes PsPAL, PsTPSs, and PsbHLH at different flower development stages and a daily change process at the full-blooming stage. The results show that there were differences in aroma components and contents of Paeonia ostii ‘Fengdan’ at different flower development stages and different time quantum of every day. There were 25 and 28 aroma components identified in 7 flower development stages of tree peonies planted in pots and in the field, respectively, and 23 and 22 aroma components identified at different time quantum of the day, of which the largest and highest content was alkanes. The main characteristic aroma substances were (E)-β-ocimene, 1,3,5-trimethoxybenzene, 2,4-di-tert-butylphenol, methyl jasmonate, nerol, and cinnamyl alcohol; released amounts of the abovementioned substances varied depending on the development stage and the time of the day. The expression of flower fragrance-controlling genes (PsPAL, PsTPSs, and PsbHLH) in tree peonies varied greatly in different conditions. The results of this study provide a valuable resource to investigate floral fragrance formation in tree peonies. Full article
(This article belongs to the Special Issue Flower Germplasm Resource and Genetic Breeding)
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14 pages, 669 KiB  
Article
Grading Criteria of Anthurium DUS Quantitative Characteristics by Multiple Comparison
by Yunxia Chu, Li Ren, Shan Deng, Shouguo Li, Yiying Zhang and Hairong Chen
Plants 2023, 12(13), 2417; https://doi.org/10.3390/plants12132417 - 22 Jun 2023
Cited by 2 | Viewed by 1670
Abstract
The determination of the grades and interval of quantitative characteristics is an important job while we draft new distinctness, uniformity and stability (DUS) test guidelines. Grading criteria should be adjusted because of the effect of year and site; it is also a key [...] Read more.
The determination of the grades and interval of quantitative characteristics is an important job while we draft new distinctness, uniformity and stability (DUS) test guidelines. Grading criteria should be adjusted because of the effect of year and site; it is also a key task to establish applicable criteria in the DUS test. Excellent criteria will improve the accuracy of the DUS evaluation. In this study, we analyzed the variability and distribution patterns of nine quantitative characteristics of 251 anthurium varieties. Three methods were used to establish the grade criteria: the two standard deviation methods, the two LSD0.05 methods and the multiple comparison method. The results showed that the coefficient of variation within varieties varied from 6.96% to 10.11%. The quantitative characteristics observed in this study did not follow a normal distribution, except spadix thickness at the middle and spathe size. In most characteristics, the standard deviations and LSD0.05 were similar, except for spathe size. The state interval set by multiple comparison methods for every characteristic was variable, and its mean was about 1.25 times that of the other two methods. The process of establishing grading criteria using the multiple comparison method was simpler, and the criteria were more accurate, with a lower error rate. Full article
(This article belongs to the Special Issue Flower Germplasm Resource and Genetic Breeding)
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Review

Jump to: Research

18 pages, 1563 KiB  
Review
The Secrets of Meristems Initiation: Axillary Meristem Initiation and Floral Meristem Initiation
by Qingqing Yang, Cunquan Yuan, Tianci Cong and Qixiang Zhang
Plants 2023, 12(9), 1879; https://doi.org/10.3390/plants12091879 - 4 May 2023
Cited by 3 | Viewed by 3146
Abstract
The branching phenotype is an extremely important agronomic trait of plants, especially for horticultural crops. It is not only an important yield character of fruit trees, but also an exquisite ornamental trait of landscape trees and flowers. The branching characteristics of plants are [...] Read more.
The branching phenotype is an extremely important agronomic trait of plants, especially for horticultural crops. It is not only an important yield character of fruit trees, but also an exquisite ornamental trait of landscape trees and flowers. The branching characteristics of plants are determined by the periodic initiation and later development of meristems, especially the axillary meristem (AM) in the vegetative stage and the floral meristem (FM) in the reproductive stage, which jointly determine the above-ground plant architecture. The regulation of meristem initiation has made great progress in model plants in recent years. Meristem initiation is comprehensively regulated by a complex regulatory network composed of plant hormones and transcription factors. However, as it is an important trait, studies on meristem initiation in horticultural plants are very limited, and the mechanism of meristem initiation regulation in horticultural plants is largely unknown. This review summarizes recent research advances in axillary meristem regulation and mainly reviews the regulatory networks and mechanisms of AM and FM initiation regulated by transcription factors and hormones. Finally, considering the existing problems in meristem initiation studies and the need for branching trait improvement in horticulture plants, we prospect future studies to accelerate the genetic improvement of the branching trait in horticulture plants. Full article
(This article belongs to the Special Issue Flower Germplasm Resource and Genetic Breeding)
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