International Journal of Molecular Sciences

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17 pages, 1287 KiB

Open AccessArticle

Study of Inheritance and Linkage of Virulence Genes in a Selfing Population of a Pakistani Dominant Race of Puccinia striiformis f. sp. tritici

by Sajid Mehmood, Marina Sajid, Syed Kamil Husnain, Jie Zhao, Lili Huang and Zhensheng Kang

Int. J. Mol. Sci. 2020, 21(5), 1685; https://doi.org/10.3390/ijms21051685 - 29 Feb 2020

Cited by 9 | Viewed by 3250

Abstract

Wheat stripe rust is a severe threat of almost all wheat-growing regions in the world. Being an obligate biotrophic fungus, Puccinia striiformis f. sp. tritici (PST) produces new virulent races that break the resistance of wheat varieties. In this study, 115 [...] Read more.

Wheat stripe rust is a severe threat of almost all wheat-growing regions in the world. Being an obligate biotrophic fungus, Puccinia striiformis f. sp. tritici (PST) produces new virulent races that break the resistance of wheat varieties. In this study, 115 progeny isolates were generated through sexual reproduction on susceptible Himalayan Berberis pseudumbellata using a dominant Pakistani race (574232) of PST. The parental isolate and progeny isolates were characterized using 24 wheat Yr single-gene lines and ten simple sequence repeat (SSR) markers. From the one-hundred-and-fifteen progeny isolates, 25 virulence phenotypes (VPs) and 60 multilocus genotypes were identified. The parental and all progeny isolates were avirulent to Yr5, Yr10, Yr15, Yr24, Yr32, Yr43, YrSp, YrTr1, YrExp2, Yr26, and YrTye and virulent to Yr1, Yr2, Yr6, Yr7, Yr8, Yr9, Yr17, Yr25, Yr27, Yr28, YrA, Yr44, and Yr3. Based on the avirulence/virulence phenotypes, we found that VPs virulent to Yr1, Yr2, Yr9, Yr17, Yr47, and YrA were controlled by one dominant gene; those to YrSp, YrTr1, and Yr10 by two dominant genes; and those to YrExp2 by two complementary dominant genes. The results are useful in breeding stripe rust-resistant wheat varieties and understanding virulence diversity. Full article

(This article belongs to the Special Issue Mapping Plant Genes that Confer Resistance to Biotic Stress)

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21 pages, 4016 KiB

Open AccessArticle

The Effect of Transcription Factor MYB14 on Defense Mechanisms in Vitis quinquangularis-Pingyi

by Yangyang Luo, Qingyang Wang, Ru Bai, Ruixiang Li, Lu Chen, Yifan Xu, Ming Zhang and Dong Duan

Int. J. Mol. Sci. 2020, 21(3), 706; https://doi.org/10.3390/ijms21030706 - 21 Jan 2020

Cited by 16 | Viewed by 3645

Abstract

In the current study, we identified a transcription factor, MYB14, from Chinese wild grape, Vitis quinquangularis-Pingyi (V. quinquangularis-PY), which could enhance the main stilbene contents and expression of stilbene biosynthesis genes (StSy/RS) by overexpression of [...] Read more.

In the current study, we identified a transcription factor, MYB14, from Chinese wild grape, Vitis quinquangularis-Pingyi (V. quinquangularis-PY), which could enhance the main stilbene contents and expression of stilbene biosynthesis genes (StSy/RS) by overexpression of VqMYB14. The promoter of VqMYB14 (pVqMYB14) was shown to be induced as part of both basal immunity (also called pathogen-associated molecular pattern (PAMP)-triggered immunity, PTI) and effector-triggered immunity (ETI), triggered by the elicitors flg22 and harpin, respectively. This was demonstrated by expression of pVqMYB14 in Nicotiana benthamiana and Vitis. We identified sequence differences, notably an 11 bp segment in pVqMYB14 that is important for the PTI/ETI, and particularly for the harpin-induced ETI response. In addition, we showed that activation of the MYB14 promoter correlates with differences in the expression of MYB14 and stilbene pattern induced by flg22 and harpin. An experimental model of upstream signaling in V. quinquangularis-PY is presented, where early defense responses triggered by flg22 and harpin partially overlap, but where the timing and levels differ. This translates into a qualitative difference with respect to patterns of stilbene accumulation. Full article

(This article belongs to the Special Issue Mapping Plant Genes that Confer Resistance to Biotic Stress)

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16 pages, 2872 KiB

Open AccessArticle

Physical Mapping of Pm57, a Powdery Mildew Resistance Gene Derived from Aegilops searsii

by Zhenjie Dong, Xiubin Tian, Chao Ma, Qing Xia, Beilin Wang, Qifan Chen, Sunish K. Sehgal, Bernd Friebe, Huanhuan Li and Wenxuan Liu

Int. J. Mol. Sci. 2020, 21(1), 322; https://doi.org/10.3390/ijms21010322 - 3 Jan 2020

Cited by 13 | Viewed by 4223

Abstract

Powdery mildew caused by Blumeria graminis f. sp. tritici (Bgt) is one of many severe diseases that threaten bread wheat (Triticum aestivum L.) yield and quality worldwide. The discovery and deployment of powdery mildew resistance genes (Pm) can [...] Read more.

Powdery mildew caused by Blumeria graminis f. sp. tritici (Bgt) is one of many severe diseases that threaten bread wheat (Triticum aestivum L.) yield and quality worldwide. The discovery and deployment of powdery mildew resistance genes (Pm) can prevent this disease epidemic in wheat. In a previous study, we transferred the powdery mildew resistance gene Pm57 from Aegilops searsii into common wheat and cytogenetically mapped the gene in a chromosome region with the fraction length (FL) 0.75–0.87, which represents 12% segment of the long arm of chromosome 2S^s#1. In this study, we performed RNA-seq using RNA extracted from leaf samples of three infected and mock-infected wheat-Ae. searsii 2S^s#1 introgression lines at 0, 12, 24, and 48 h after inoculation with Bgt isolates. Then we designed 79 molecular markers based on transcriptome sequences and physically mapped them to Ae. searsii chromosome 2S^s#1- in seven intervals. We used these markers to identify 46 wheat-Ae. searsii 2S^s#1 recombinants induced by ph1b, a deletion mutant of pairing homologous (Ph) genes. After analyzing the 46 ph1b-induced 2S^s#1L recombinants in the region where Pm57 is located with different Bgt-responses, we physically mapped Pm57 gene on the long arm of 2S^s#1 in a 5.13 Mb genomic region, which was flanked by markers X67593 (773.72 Mb) and X62492 (778.85 Mb). By comparative synteny analysis of the corresponding region on chromosome 2B in Chinese Spring (T. aestivum L.) with other model species, we identified ten genes that are putative plant defense-related (R) genes which includes six coiled-coil nucleotide-binding site-leucine-rich repeat (CNL), three nucleotide-binding site-leucine-rich repeat (NL) and a leucine-rich receptor-like repeat (RLP) encoding proteins. This study will lay a foundation for cloning of Pm57, and benefit the understanding of interactions between resistance genes of wheat and powdery mildew pathogens. Full article

(This article belongs to the Special Issue Mapping Plant Genes that Confer Resistance to Biotic Stress)

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20 pages, 2449 KiB

Open AccessArticle

Identification of a Major QTL (qRRs-10.1) That Confers Resistance to Ralstonia solanacearum in Pepper (Capsicum annuum) Using SLAF-BSA and QTL Mapping

by Heshan Du, Changlong Wen, Xiaofen Zhang, Xiulan Xu, Jingjing Yang, Bin Chen and Sansheng Geng

Int. J. Mol. Sci. 2019, 20(23), 5887; https://doi.org/10.3390/ijms20235887 - 23 Nov 2019

Cited by 37 | Viewed by 6095

Abstract

The soilborne pathogen Ralstonia solanacearum is the causal agent of bacterial wilt (BW), a major disease of pepper (Capsicum annuum). The genetic basis of resistance to this disease in pepper is not well known. This study aimed to identify BW resistance [...] Read more.

The soilborne pathogen Ralstonia solanacearum is the causal agent of bacterial wilt (BW), a major disease of pepper (Capsicum annuum). The genetic basis of resistance to this disease in pepper is not well known. This study aimed to identify BW resistance markers in pepper. Analysis of the dynamics of bioluminescent R. solanacearum colonization in reciprocal grafts of a resistant (BVRC 1) line and a susceptible (BVRC 25) line revealed that the resistant rootstock effectively suppressed the spreading of bacteria into the scion. The two clear-cut phenotypic distributions of the disease severity index in 440 F2 plants derived from BVRC 25 × BVRC 1 indicated that a major genetic factor as well as a few minor factors that control BW resistance. By specific-locus amplified fragment sequencing combined with bulked segregant analysis, two adjacent resistance-associated regions on chromosome 10 were identified. Quantitative trait (QTL) mapping revealed that these two regions belong to a single QTL, qRRs-10.1. The marker ID10-194305124, which reached a maximum log-likelihood value at 9.79 and accounted for 19.01% of the phenotypic variation, was located the closest to the QTL peak. A cluster of five predicted R genes and three defense-related genes, which are located in close proximity to the significant markers ID10-194305124 or ID10-196208712, are important candidate genes that may confer BW resistance in pepper. Full article

(This article belongs to the Special Issue Mapping Plant Genes that Confer Resistance to Biotic Stress)

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12 pages, 627 KiB

Open AccessArticle

Characterization of QTLs for Seedling Resistance to Tan Spot and Septoria Nodorum Blotch in the PBW343/Kenya Nyangumi Wheat Recombinant Inbred Lines Population

by Pawan Kumar Singh, Sukhwinder Singh, Zhiying Deng, Xinyao He, Zakaria Kehel and Ravi Prakash Singh

Int. J. Mol. Sci. 2019, 20(21), 5432; https://doi.org/10.3390/ijms20215432 - 31 Oct 2019

Cited by 13 | Viewed by 3629

Abstract

Tan spot (TS) and Septoria nodorum blotch (SNB) induced by Pyrenophora tritici-repentis and Parastagonospora nodorum, respectively, cause significant yield losses and adversely affect grain quality. The objectives of this study were to decipher the genetics and map the resistance to TS and [...] Read more.

Tan spot (TS) and Septoria nodorum blotch (SNB) induced by Pyrenophora tritici-repentis and Parastagonospora nodorum, respectively, cause significant yield losses and adversely affect grain quality. The objectives of this study were to decipher the genetics and map the resistance to TS and SNB in the PBW343/Kenya Nyangumi (KN) population comprising 204 F₆ recombinant inbred lines (RILs). Disease screening was performed at the seedling stage under greenhouse conditions. TS was induced by P. tritici-repentis isolate MexPtr1 while SNB by P. nodorum isolate MexSN1. Segregation pattern of the RILs indicated that resistance to TS and SNB in this population was quantitative. Diversity Array Technology (DArTs) and simple sequence repeats (SSRs) markers were used to identify the quantitative trait loci (QTL) for the diseases using inclusive composite interval mapping (ICIM). Seven significant additive QTLs for TS resistance explaining 2.98 to 23.32% of the phenotypic variation were identified on chromosomes 1A, 1B, 5B, 7B and 7D. For SNB, five QTLs were found on chromosomes 1A, 5A, and 5B, explaining 5.24 to 20.87% of the phenotypic variation. The TS QTL on 1B chromosome coincided with the pleiotropic adult plant resistance (APR) gene Lr46/Yr29/Pm39. This is the first report of the APR gene Lr46/Yr29/Pm39 contributing to TS resistance. Full article

(This article belongs to the Special Issue Mapping Plant Genes that Confer Resistance to Biotic Stress)

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13 pages, 4113 KiB

Open AccessArticle

Physical Mapping of Stem Rust Resistance Gene Sr52 from Dasypyrum villosum Based on ph1b-Induced Homoeologous Recombination

by Huanhuan Li, Zhenjie Dong, Chao Ma, Xiubin Tian, Zengjun Qi, Nan Wu, Bernd Friebe, Zhiguo Xiang, Qing Xia, Wenxuan Liu and Tianya Li

Int. J. Mol. Sci. 2019, 20(19), 4887; https://doi.org/10.3390/ijms20194887 - 2 Oct 2019

Cited by 17 | Viewed by 2953

Abstract

Wheat stem rust caused by Puccinia graminis f. sp. tritici (Pgt) had been a devastating foliar disease worldwide during the 20th century. With the emergence of Ug99 races, which are virulent to most stem rust resistance genes deployed in wheat varieties [...] Read more.

Wheat stem rust caused by Puccinia graminis f. sp. tritici (Pgt) had been a devastating foliar disease worldwide during the 20th century. With the emergence of Ug99 races, which are virulent to most stem rust resistance genes deployed in wheat varieties and advanced lines, stem rust has once again become a disease threatening global wheat production. Sr52, derived from Dasypyrum villosum and mapped to the long arm of 6V#3, is one of the few effective genes against Ug99 races. In this study, the wheat–D. villosum Robertsonian translocation T6AS·6V#3L, the only stock carrying Sr52 released to experimental and breeding programs so far, was crossed with a CS ph1b mutant to induce recombinants with shortened 6V#3L chromosome segments locating Sr52. Six independent homozygous recombinants with different segment sizes and breakpoints were developed and characterized using in situ hybridization and molecular markers analyses. Stem rust resistance evaluation showed that only three terminal recombinants (1381, 1380, and 1392) containing 8%, 22%, and 30% of the distal segment of 6V#3L, respectively, were resistant to stem rust. Thus, the gene Sr52 was mapped into 6V#3L bin FL 0.92–1.00. In addition, three molecular markers in the Sr52-located interval of 6V#3L were confirmed to be diagnostic markers for selection of Sr52 introgressed into common wheat. The newly developed small segment translocation lines with Sr52 and the identified molecular markers closely linked to Sr52 will be valuable for wheat disease breeding. Full article

(This article belongs to the Special Issue Mapping Plant Genes that Confer Resistance to Biotic Stress)

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15 pages, 1502 KiB

Open AccessArticle

Genome-Wide Association Study for Multiple Biotic Stress Resistance in Synthetic Hexaploid Wheat

by Madhav Bhatta, Alexey Morgounov, Vikas Belamkar, Stephen N. Wegulo, Abdelfattah A. Dababat, Gül Erginbas-Orakci, Mustapha El Bouhssini, Pravin Gautam, Jesse Poland, Nilüfer Akci, Lütfü Demir, Ruth Wanyera and P. Stephen Baenziger

Int. J. Mol. Sci. 2019, 20(15), 3667; https://doi.org/10.3390/ijms20153667 - 26 Jul 2019

Cited by 33 | Viewed by 5588

Abstract

Genetic resistance against biotic stress is a major goal in many wheat breeding programs. However, modern wheat cultivars have a limited genetic variation for disease and pest resistance and there is always a possibility of the evolution of new diseases and pests to [...] Read more.

Genetic resistance against biotic stress is a major goal in many wheat breeding programs. However, modern wheat cultivars have a limited genetic variation for disease and pest resistance and there is always a possibility of the evolution of new diseases and pests to overcome previously identified resistance genes. A total of 125 synthetic hexaploid wheats (SHWs; 2n = 6x = 42, AABBDD, Triticum aestivum L.) were characterized for resistance to fungal pathogens that cause wheat rusts (leaf; Puccinia triticina, stem; P. graminis f.sp. tritici, and stripe; P. striiformis f.sp. tritici) and crown rot (Fusarium spp.); cereal cyst nematode (Heterodera spp.); and Hessian fly (Mayetiola destructor). A wide range of genetic variation was observed among SHWs for multiple (two to five) biotic stresses and 17 SHWs that were resistant to more than two stresses. The genomic regions and potential candidate genes conferring resistance to these biotic stresses were identified from a genome-wide association study (GWAS). This GWAS study identified 124 significant marker-trait associations (MTAs) for multiple biotic stresses and 33 of these were found within genes. Furthermore, 16 of the 33 MTAs present within genes had annotations suggesting their potential role in disease resistance. These results will be valuable for pyramiding novel genes/genomic regions conferring resistance to multiple biotic stresses from SHWs into elite bread wheat cultivars and providing further insights on a wide range of stress resistance in wheat. Full article

(This article belongs to the Special Issue Mapping Plant Genes that Confer Resistance to Biotic Stress)

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16 pages, 2712 KiB

Open AccessArticle

Identification of QTLs for Stripe Rust Resistance in a Recombinant Inbred Line Population

by Manyu Yang, Guangrong Li, Hongshen Wan, Liping Li, Jun Li, Wuyun Yang, Zongjun Pu, Zujun Yang and Ennian Yang

Int. J. Mol. Sci. 2019, 20(14), 3410; https://doi.org/10.3390/ijms20143410 - 11 Jul 2019

Cited by 28 | Viewed by 3373

Abstract

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most devastating fungal diseases of wheat worldwide. It is essential to discover more sources of stripe rust resistance genes for wheat breeding programs. Specific locus amplified fragment [...] Read more.

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most devastating fungal diseases of wheat worldwide. It is essential to discover more sources of stripe rust resistance genes for wheat breeding programs. Specific locus amplified fragment sequencing (SLAF-seq) is a powerful tool for the construction of high-density genetic maps. In this study, a set of 200 recombinant inbred lines (RILs) derived from a cross between wheat cultivars Chuanmai 42 (CH42) and Chuanmai 55 (CH55) was used to construct a high-density genetic map and to identify quantitative trait loci (QTLs) for stripe rust resistance using SLAF-seq technology. A genetic map of 2828.51 cM, including 21 linkage groups, contained 6732 single nucleotide polymorphism markers (SNP). Resistance QTLs were identified on chromosomes 1B, 2A, and 7B; Qyr.saas-7B was derived from CH42, whereas Qyr.saas-1B and Qyr.saas-2A were from CH55. The physical location of Qyr.saas-1B, which explained 6.24–34.22% of the phenotypic variation, overlapped with the resistance gene Yr29. Qyr.saas-7B accounted for up to 20.64% of the phenotypic variation. Qyr.saas-2A, a minor QTL, was found to be a likely new stripe rust resistance locus. A significant additive effect was observed when all three QTLs were combined. The combined resistance genes could be of value in breeding wheat for stripe rust resistance. Full article

(This article belongs to the Special Issue Mapping Plant Genes that Confer Resistance to Biotic Stress)

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16 pages, 6896 KiB

Open AccessArticle

LMM24 Encodes Receptor-Like Cytoplasmic Kinase 109, Which Regulates Cell Death and Defense Responses in Rice

by Yue Zhang, Qunen Liu, Yingxin Zhang, Yuyu Chen, Ning Yu, Yongrun Cao, Xiaodeng Zhan, Shihua Cheng and Liyong Cao

Int. J. Mol. Sci. 2019, 20(13), 3243; https://doi.org/10.3390/ijms20133243 - 2 Jul 2019

Cited by 24 | Viewed by 3988

Abstract

Lesion mimic mutants are excellent models for research on molecular mechanisms of cell death and defense responses in rice. We identified a new rice lesion mimic mutant lmm24 from a mutant pool of indica rice cultivar “ZhongHui8015”. The LMM24 gene was identified by [...] Read more.

Lesion mimic mutants are excellent models for research on molecular mechanisms of cell death and defense responses in rice. We identified a new rice lesion mimic mutant lmm24 from a mutant pool of indica rice cultivar “ZhongHui8015”. The LMM24 gene was identified by MutMap, and LMM24 was confirmed as a receptor-like cytoplasmic kinase 109 by amino acid sequence analysis. The lmm24 mutant displayed dark brown lesions in leaves and growth retardation that were not observed in wild-type ZH8015. The results of histochemical staining and TUNEL assays showed enhanced ROS accumulation and cell death in lmm24. Chloroplast degradation was observed in lmm24 leaves, with decreased expression of photosynthesis-related genes and increased expression of the senescence-induced STAYGREEN (SGR) gene and other senescence-associated genes. Furthermore, lmm24 exhibited enhanced resistance to rice blast fungus Magnaporthe oryzae (M. oryzae) and up-regulation of defense response genes. Our data demonstrate that LMM24 regulates cell death and defense responses in rice. Full article

(This article belongs to the Special Issue Mapping Plant Genes that Confer Resistance to Biotic Stress)

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15 pages, 2171 KiB

Open AccessArticle

Genome Wide Association Study of Karnal Bunt Resistance in a Wheat Germplasm Collection from Afghanistan

by Vikas Gupta, Xinyao He, Naresh Kumar, Guillermo Fuentes-Davila, Rajiv K. Sharma, Susanne Dreisigacker, Philomin Juliana, Najibeh Ataei and Pawan K. Singh

Int. J. Mol. Sci. 2019, 20(13), 3124; https://doi.org/10.3390/ijms20133124 - 26 Jun 2019

Cited by 27 | Viewed by 4097

Abstract

Karnal bunt disease of wheat, caused by the fungus Neovossia indica, is one of the most important challenges to the grain industry as it affects the grain quality and also restricts the international movement of infected grain. It is a seed-, soil- [...] Read more.

Karnal bunt disease of wheat, caused by the fungus Neovossia indica, is one of the most important challenges to the grain industry as it affects the grain quality and also restricts the international movement of infected grain. It is a seed-, soil- and airborne disease with limited effect of chemical control. Currently, this disease is contained through the deployment of host resistance but further improvement is limited as only a few genotypes have been found to carry partial resistance. To identify genomic regions responsible for resistance in a set of 339 wheat accessions, genome-wide association study (GWAS) was undertaken using the DArTSeq^® technology, in which 18 genomic regions for Karnal bunt resistance were identified, explaining 5–20% of the phenotypic variation. The identified quantitative trait loci (QTL) on chromosome 2BL showed consistently significant effects across all four experiments, whereas another QTL on 5BL was significant in three experiments. Additional QTLs were mapped on chromosomes 1DL, 2DL, 4AL, 5AS, 6BL, 6BS, 7BS and 7DL that have not been mapped previously, and on chromosomes 4B, 5AL, 5BL and 6BS, which have been reported in previous studies. Germplasm with less than 1% Karnal bunt infection have been identified and can be used for resistance breeding. The SNP markers linked to the genomic regions conferring resistance to Karnal bunt could be used to improve Karnal bunt resistance through marker-assisted selection. Full article

(This article belongs to the Special Issue Mapping Plant Genes that Confer Resistance to Biotic Stress)

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12 pages, 1914 KiB

Open AccessArticle

Rice Genome Resequencing Reveals a Major Quantitative Trait Locus for Resistance to Bakanae Disease Caused by Fusarium fujikuroi

by Do-Yu Kang, Kyeong-Seong Cheon, Jun Oh, Hyoja Oh, Song Lim Kim, Nyunhee Kim, Eungyeong Lee, Inchan Choi, Jeongho Baek, Kyung-Hwan Kim, Nam-Jin Chung and Hyeonso Ji

Int. J. Mol. Sci. 2019, 20(10), 2598; https://doi.org/10.3390/ijms20102598 - 27 May 2019

Cited by 31 | Viewed by 4275

Abstract

Bakanae disease (BD), caused by the fungal pathogen Fusarium fujikuroi, has become a serious threat in rice-cultivating regions worldwide. In the present study, quantitative trait locus (QTL) mapping was performed using F2 and F3 plants derived after crossing a BD-resistant and a [...] Read more.

Bakanae disease (BD), caused by the fungal pathogen Fusarium fujikuroi, has become a serious threat in rice-cultivating regions worldwide. In the present study, quantitative trait locus (QTL) mapping was performed using F2 and F3 plants derived after crossing a BD-resistant and a BD-susceptible Korean japonica rice variety, ‘Samgwang’ and ‘Junam’, respectively. Resequencing of ‘Junam’ and ‘Samgwang’ genomes revealed 151,916 DNA polymorphisms between the two varieties. After genotyping 188 F2 plants, we constructed a genetic map comprising 184 markers, including 175 kompetitive allele-specific PCR markers, eight cleaved amplified polymorphic sequence (CAPS) markers, and a derived CAPS (dCAPS) marker. The degree of BD susceptibility of each F2 plant was evaluated on the basis of the mortality rate measured with corresponding F3 progeny seedlings by in vitro screening. Consequently, qFfR9, a major QTL, was discovered at 30.1 centimorgan (cM) on chromosome 9 with a logarithm of the odds score of 60.3. For the QTL interval, 95% probability lay within a 7.24–7.56 Mbp interval. In this interval, we found that eight genes exhibited non-synonymous single nucleotide polymorphisms (SNPs) by comparing the ‘Junam’ and ‘Samgwang’ genome sequence data, and are possibly candidate genes for qFfR9; therefore, qFfR9 could be utilized as a valuable resource for breeding BD-resistant rice varieties. Full article

(This article belongs to the Special Issue Mapping Plant Genes that Confer Resistance to Biotic Stress)

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17 pages, 2970 KiB

Open AccessArticle

Genetic Mapping and Molecular Characterization of a Broad-spectrum Phytophthora sojae Resistance Gene in Chinese Soybean

by Chao Zhong, Yinping Li, Suli Sun, Canxing Duan and Zhendong Zhu

Int. J. Mol. Sci. 2019, 20(8), 1809; https://doi.org/10.3390/ijms20081809 - 12 Apr 2019

Cited by 33 | Viewed by 4148

Abstract

Phytophthora root rot (PRR) causes serious annual soybean yield losses worldwide. The most effective method to prevent PRR involves growing cultivars that possess genes conferring resistance to Phytophthora sojae (Rps). In this study, QTL-sequencing combined with genetic mapping was used to identify RpsX [...] Read more.

Phytophthora root rot (PRR) causes serious annual soybean yield losses worldwide. The most effective method to prevent PRR involves growing cultivars that possess genes conferring resistance to Phytophthora sojae (Rps). In this study, QTL-sequencing combined with genetic mapping was used to identify RpsX in soybean cultivar Xiu94-11 resistance to all P. sojae isolates tested, exhibiting broad-spectrum PRR resistance. Subsequent analysis revealed RpsX was located in the 242-kb genomic region spanning the RpsQ locus. However, a phylogenetic investigation indicated Xiu94-11 carrying RpsX is distantly related to the cultivars containing RpsQ, implying RpsX and RpsQ have different origins. An examination of candidate genes revealed RpsX and RpsQ share common nonsynonymous SNP and a 144-bp insertion in the Glyma.03g027200 sequence encoding a leucine-rich repeat (LRR) region. Glyma.03g027200 was considered to be the likely candidate gene of RpsQ and RpsX. Sequence analyses confirmed that the 144-bp insertion caused by an unequal exchange resulted in two additional LRR-encoding fragments in the candidate gene. A marker developed based on the 144-bp insertion was used to analyze the genetic population and germplasm, and proved to be useful for identifying the RpsX and RpsQ alleles. This study implies that the number of LRR units in the LRR domain may be important for PRR resistance in soybean. Full article

(This article belongs to the Special Issue Mapping Plant Genes that Confer Resistance to Biotic Stress)

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