Influence of Rhizoctonia solani and Trichoderma spp. in growth of bean (Phaseolus vulgaris L.) and in the induction of plant defense-related genes

Sara Mayo,M Piedad Campelo,Rosa Hermosa,Santiago Gutiérrez,Monica G Malmierca,Pedro A Casquero,Alicia Lorenzana

doi:10.3389/fpls.2015.00685

Sara Mayo, M Piedad Campelo + Show 5 more

Open Access

https://doi.org/10.3389/fpls.2015.00685

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Abstract

Many Trichoderma species are well-known for their ability to promote plant growth and defense. We study how the interaction of bean plants with R. solani and/or Trichoderma affect the plants growth and the level of expression of defense-related genes. Trichoderma isolates were evaluated in vitro for their potential to antagonize R. solani. Bioassays were performed in climatic chambers and development of the plants was evaluated. The effect of Trichoderma treatment and/or R. solani infection on the expression of bean defense-related genes was analyzed by real-time PCR and the production of ergosterol and squalene was quantified. In vitro growth inhibition of R. solani was between 86 and 58%. In in vivo assays, the bean plants treated with Trichoderma harzianum T019 always had an increased size respect to control and the plants treated with this isolate did not decrease their size in presence of R. solani. The interaction of plants with R. solani and/or Trichoderma affects the level of expression of seven defense-related genes. Squalene and ergosterol production differences were found among the Trichoderma isolates, T019 showing the highest values for both compounds. T. harzianum T019 shows a positive effect on the level of resistance of bean plants to R. solani. This strain induces the expression of plant defense-related genes and produces a higher level of ergosterol, indicating its ability to grow at a higher rate in the soil, which would explain its positive effects on plant growth and defense in the presence of the pathogen.

Highlights

The common bean (Phaseolus vulgaris L.) is the third most important food legume crop worldwide, surpassed only by the soybean [Glycine max (L.) Merr.] and peanut (Arachis hypogea L.)
Analysis of the in vitro Antagonistic Activity of Trichoderma Isolates with R. solani The first test to determine the in vitro antifungal ability of the different Trichoderma isolates was based on their ability to produce metabolites that may inhibit the growth of R. solani (Table 3, Figure 1A)
Trichoderma isolates inhibit the development of R. solani under in vitro conditions, when they grow in Petri dishes

Summary

Introduction

The common bean (Phaseolus vulgaris L.) is the third most important food legume crop worldwide, surpassed only by the soybean [Glycine max (L.) Merr.] and peanut (Arachis hypogea L.). Among the southern countries of the European Union, Spain together with Italy and Greece are the main common bean producers. A province located at the northwest of Spain, is Tricho-rhizoc bean genes the main producer province by quantity and quality, with almost 45% of Spanish production in 2014. The high quality of this legume has been awarded with a Protected Geographic Indication (PGI) (EC Reg. n.256/2010 published on 26 March 2010, OJEU L880/17). In the last few years, dry bean production has gone through difficulties due to relatively low yields (mainly caused by fungus, virus, and bacteria) and insufficient income for growers

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