Agriculture

Research

13 pages, 2083 KiB

Open AccessArticle

Assessing the Influence of Fumigation and Bacillus Subtilis-Based Biofungicide on the Microbiome of Chrysanthemum Rhizosphere

by Huijie Chen, Jiamiao Zhao, Jing Jiang, Sumei Chen, Zhiyong Guan, Fadi Chen, Weimin Fang and Shuang Zhao

Agriculture 2019, 9(12), 255; https://doi.org/10.3390/agriculture9120255 - 1 Dec 2019

Cited by 9 | Viewed by 3753

Abstract

Chrysanthemum is an important ornamental species in China. However, sustained monoculture often leads to a decline in soil quality, in particular to the build-up of pathogens. Fusarium wilt, a severe disease in chrysanthemum monoculture systems, was effectively controlled by fumigation and/or the application [...] Read more.

Chrysanthemum is an important ornamental species in China. However, sustained monoculture often leads to a decline in soil quality, in particular to the build-up of pathogens. Fusarium wilt, a severe disease in chrysanthemum monoculture systems, was effectively controlled by fumigation and/or the application of a biofungicide in our previous study. However, the mechanisms underlying disease suppression remain elusive. Here, a series of greenhouse experiments were conducted to characterize the effect on the chrysanthemum rhizosphere microbiome of the fumigant dazomet (DZ) and of a biofungicide based on Bacillus subtilis NCD-2 (BF). The results indicated that the BF treatment increased bacterial diversity by 4.2%, while decreasing fungal diversity by 21.3%. After two seasons of BF treatment, the abundance of microbes associated with disease suppression such as Bacillus spp. and Trichoderma spp. increased 15.1-fold and 4.25-fold more than that of the control, while the pathogenic Fusarium oxysporum was decreased by 79.20% when compared to the control. Besides, the DZ treatment reduced both bacterial and fungal diversity 7.97% and 2.73% respectively, when compared with the control. The DZ treatment controlled Fusarium wilt disease and decreased the abundance of F. oxysporum in the first year, but the abundance of the F. oxysporum was 43.8% higher after two years in treated soil than in non-treated soil. Therefore, the application of BF has a great potential for the control of Fusarium wilt disease in chrysanthemum by changing soil microbiome structure and function. Full article

(This article belongs to the Special Issue Plant-Microbe Interactions)

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15 pages, 2440 KiB

Open AccessArticle

Impact of Colletotrichum acutatum Pathogen on Olive Phenylpropanoid Metabolism

by Irene Gouvinhas, Paula Martins-Lopes, Teresa Carvalho, Ana Barros and Sónia Gomes

Agriculture 2019, 9(8), 173; https://doi.org/10.3390/agriculture9080173 - 6 Aug 2019

Cited by 17 | Viewed by 4998

Abstract

Olive anthracnose caused by the hemibiotrophic fungal pathogen Colletotrichum acutatum is a serious threat to the olive sector. Olive oil and fruit production is severely constrained by Colletotrichum spp. infection, being C. acutatum the most distributed pathogen in Portuguese olive orchards. To understand [...] Read more.

Olive anthracnose caused by the hemibiotrophic fungal pathogen Colletotrichum acutatum is a serious threat to the olive sector. Olive oil and fruit production is severely constrained by Colletotrichum spp. infection, being C. acutatum the most distributed pathogen in Portuguese olive orchards. To understand the impact of C. acutatum on phenylpropanoids biosynthesis, the enzyme activity, phenolic compounds, ortho-diphenols, and flavonoids content were determined and correlated with the expression of gene encoding key enzymes within phenylpropanoids metabolism in susceptible and tolerant olive fruits, during maturation and when infected with C. acutatum. Differences between cultivars was observed, the tolerant olive cv. Picual presented a higher basal value and a stable phenolic content throughout the infection process, supporting its high C. acutatum tolerance, whereas in the susceptible olive cv. Galega these secondary metabolites were significantly increased only after the elicitation with C. acutatum. Full article

(This article belongs to the Special Issue Plant-Microbe Interactions)

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15 pages, 625 KiB

Open AccessArticle

Tomato Yield, Quality, Mineral Composition and Antioxidants as Affected by Beneficial Microorganisms Under Soil Salinity Induced by Balanced Nutrient Solutions

by Vincenzo Michele Sellitto, Nadezhda A. Golubkina, Laura Pietrantonio, Eugenio Cozzolino, Antonio Cuciniello, Vincenzo Cenvinzo, Imbrea Florin and Gianluca Caruso

Agriculture 2019, 9(5), 110; https://doi.org/10.3390/agriculture9050110 - 23 May 2019

Cited by 41 | Viewed by 7343

Abstract

With the aim of assessing the effects of beneficial microorganisms on greenhouse tomato “plum” grown under salinity conditions, research was carried out in southern Italy from summer to winter, by comparing two arbuscular mycorrhizal fungi (AMF) based formulates (Rizotech Plus, Myco Apply DR) [...] Read more.

With the aim of assessing the effects of beneficial microorganisms on greenhouse tomato “plum” grown under salinity conditions, research was carried out in southern Italy from summer to winter, by comparing two arbuscular mycorrhizal fungi (AMF) based formulates (Rizotech Plus, Myco Apply DR) and a non-inoculated control, in factorial combination with four soil electrical conductivities (1.5, 3.0, 4.5, 6.0 mS·cm⁻¹ EC). The highest root colonization was 83% at 3.0 mS·cm⁻¹ under AMF-based treatments and 34% at 1.5 mS·cm⁻¹ in non-treated control; the latter attained lower values than AMF treatments at any soil EC. Harvest occurred 3.5 days earlier in control plants, six days earlier under 6.0 mS·cm⁻¹ EC compared to 1.5 mS·cm⁻¹. The inoculated plants always showed higher yield than the control ones and the highest production at 4.5 mS·cm⁻¹ EC; control plants attained the highest yield under 3.0–4.5 mS·cm⁻¹ EC. The highest values of most fruit quality indicators, mineral elements and antioxidant compounds and activity were recorded under AMF-based formulates inoculation and 6.0 mS·cm⁻¹ soil EC. Beneficial microorganisms proved to be an effective environmentally friendly tool for improving tomato yield and quality performances in both normal and soil salinity conditions. Full article

(This article belongs to the Special Issue Plant-Microbe Interactions)

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0 pages, 630 KiB

Open AccessArticle

Inoculation with Mycorrhizal Fungi and Other Microbes to Improve the Morpho-Physiological and Floral Traits of Gazania rigens (L.) Gaertn

by Ishan Saini, Ashok Aggarwal and Prashant Kaushik

Agriculture 2019, 9(3), 51; https://doi.org/10.3390/agriculture9030051 - 8 Mar 2019

Cited by 27 | Viewed by 6418 | Correction

Abstract

In the present analysis, we evaluated the effect of different microbial inoculants on growth and floral responses of Gazania rigens (L.) Gaertn. Two prevailing arbuscular mycorrhizal fungi (AMF) i.e., Funelliformis mosseae and Acaulospora laevis, along with Trichoderma viride and Pseudomonas fluorescens, [...] Read more.

In the present analysis, we evaluated the effect of different microbial inoculants on growth and floral responses of Gazania rigens (L.) Gaertn. Two prevailing arbuscular mycorrhizal fungi (AMF) i.e., Funelliformis mosseae and Acaulospora laevis, along with Trichoderma viride and Pseudomonas fluorescens, were examined in a pot experiment. Independent roles of these four microbes and their different combinations were used in sixteen treatments of G. rigens. The experiment was conducted in a polyhouse with five replicates per treatment in a randomized complete block design. The results of microbial inoculants were very effective for growth yield and flowering response over the control. Early flowering was noted in the combination of F. mosseae, A. laevis and P. fluorescens, which also showed the best results for flower head size, flower fresh and dry weight, total chlorophyll, carotene and phosphorus content. Arbuscular mycorrhiza (AM) root colonization (%) and AM spore number were also the highest for the same treatment, whereas the number of leaves, number of buds and root length were maximum in the combined treatment (F. mosseae + A. laevis + T. viride + P. fluorescens). Overall, this study proposes that growers should consider microbial inoculants for the better yield and flower quality of G. rigens. Full article

(This article belongs to the Special Issue Plant-Microbe Interactions)

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11 pages, 2462 KiB

Open AccessArticle

Regional Evaluation of Fungal Pathogen Incidence in Colombian Cocoa Crops

by Raquel Villamizar-Gallardo, Johann F. Osma and Oscar Orlando Ortíz-Rodriguez

Agriculture 2019, 9(3), 44; https://doi.org/10.3390/agriculture9030044 - 4 Mar 2019

Cited by 7 | Viewed by 5404

Abstract

The production of cocoa (Theobroma cacao L.) in Colombia has a significant environmental and socioeconomic importance as a promissory crop in the post-conflict process. The department of Norte de Santander has cocoa crops that are dramatically affected by fungal pathogens causing important [...] Read more.

The production of cocoa (Theobroma cacao L.) in Colombia has a significant environmental and socioeconomic importance as a promissory crop in the post-conflict process. The department of Norte de Santander has cocoa crops that are dramatically affected by fungal pathogens causing important losses during harvest and post-harvest. Therefore, the current study focused on the determination of the incidence of diseases caused by phytopathogenic fungi in cocoa crops, and the identification of primary phytopathogenic fungi found in biological material from different farms of the region. The study was conducted in four municipalities of the department, by sampling fruits infected with frosty pod rot (FPR) and black pod rot (BPR) that presented in situ incidence ranging from 0.37 to 21.58% and from 1.75 to 35.59%, respectively. The studied hybrid materials, together with clone TSH 65, were found to be the most susceptible, while the remaining clones were more tolerant, especially CCN 51, IMC 67, and ICS95. Fifteen strains were isolated using in vitro assays and then morphologically characterized both in solid media and by microscopy. Nine of them corresponded to the pathogen Moniliophthora roreri, and other six to Phytophthora palmivora. The isolated agents showed in vitro morphological variability, as well as the ability to adapt to different environments when growing in situ. Full article

(This article belongs to the Special Issue Plant-Microbe Interactions)

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15 pages, 1743 KiB

Open AccessArticle

Evaluation of Soil-Applied Chemical Fungicide and Biofungicide for Control of the Fusarium Wilt of Chrysanthemum and Their Effects on Rhizosphere Soil Microbiota

by Huijie Chen, Shuang Zhao, Kaikai Zhang, Jiamiao Zhao, Jing Jiang, Fadi Chen and Weimin Fang

Agriculture 2018, 8(12), 184; https://doi.org/10.3390/agriculture8120184 - 23 Nov 2018

Cited by 17 | Viewed by 5426

Abstract

Chemical fungicides are a frequently used intervention for the control of the Fusarium wilt of chrysanthemum, but are no longer considered environmentally friendly. However, the biofungicides offer one of the best alternatives to reduce the use of chemical fungicides. In this study, a [...] Read more.

Chemical fungicides are a frequently used intervention for the control of the Fusarium wilt of chrysanthemum, but are no longer considered environmentally friendly. However, the biofungicides offer one of the best alternatives to reduce the use of chemical fungicides. In this study, a series of two-year greenhouse experiments were conducted to evaluate the soil-applied chemical fungicide (dazomet, DZ) and biofungicide (biocontrol agent combined with B. subtilis NCD-2, BF) for controlling the Fusarium wilt of chrysanthemum and its effects on rhizosphere soil microbiota. The results indicated that DZ and BF showed good control efficacy of Fusarium wilt of chrysanthemum in the two-year application evaluation. However, the DZ treatment significantly decreased the soil catalase and urease activities compared with the control, while BF showed a significant increase in bacterium/fungus ratios (B/F), soil urease and acid phosphatase activities. Abundances of potential plant pathogens F. oxysporum, Rhizoctonia zeae and Rhizoctonia solani were also lower, while potential plant-growth-promoting micro-organisms like the Rhizobiales bacterium and Mariniflexile sp. were higher in the BF treatment than in the control. Our findings suggested that the overall effect of the soil biota on chrysanthemum growth was more positive and stronger in the BF treatment than in the DZ treatment. Full article

(This article belongs to the Special Issue Plant-Microbe Interactions)

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Review

Jump to: Research, Other

13 pages, 881 KiB

Open AccessReview

The Interactions of Rhizodeposits with Plant Growth-Promoting Rhizobacteria in the Rhizosphere: A Review

by Mohammad K. Hassan, John A. McInroy and Joseph W. Kloepper

Agriculture 2019, 9(7), 142; https://doi.org/10.3390/agriculture9070142 - 4 Jul 2019

Cited by 191 | Viewed by 21645

Abstract

Rhizodeposits, root exudates, and root border cells are vital components of the rhizosphere that significantly affect root colonization capacity and multiplication of rhizosphere microbes, as well as secretion of organic bioactive compounds. The rhizosphere is an ecological niche, in which beneficial bacteria compete [...] Read more.

Rhizodeposits, root exudates, and root border cells are vital components of the rhizosphere that significantly affect root colonization capacity and multiplication of rhizosphere microbes, as well as secretion of organic bioactive compounds. The rhizosphere is an ecological niche, in which beneficial bacteria compete with other microbiota for organic carbon compounds and interact with plants through root colonization activity to the soil. Some of these root-colonizing beneficial rhizobacteria also colonize endophytically and multiply inside plant roots. In the rhizosphere, these components contribute to complex physiological processes, including cell growth, cell differentiation, and suppression of plant pathogenic microbes. Understanding how rhizodeposits, root exudates, and root border cells interact in the rhizosphere in the presence of rhizobacterial populations is necessary to decipher their synergistic role for the improvement of plant health. This review highlights the diversity of plant growth-promoting rhizobacteria (PGPR) genera, their functions, and the interactions with rhizodeposits in the rhizosphere. Full article

(This article belongs to the Special Issue Plant-Microbe Interactions)

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