Native Trichoderma strains promote growth and biocontrol in Medicago sativa and Arabidopsis thaliana plants.

JAIME CL.; MÁZZARO, V.; COMELLI R.; SELUY L.; BENZZO M.; DUNGER R.

Encuentro; SAIB - SAMIGE Joint meeting 2021; 2021

SAIB Argentina

Alfalfa (Medicago sativa L.) is an important legume forage grown worldwide with around 35 million hectares cultivated overmore than 80 countries. Due to the expansion of extensive crops, alfalfa production has shifted to marginal areas with poorlydrained soils, which directly affects the productivity and persistence of this crop. Biological control provides an alternative tothe use of synthetic pesticides with the advantages of greater public acceptance and lower environmental impact. The use ofrhizospheric microorganisms as biological control agents seeks to restore the beneficial balance of natural ecosystems.Trichoderma is a genus of filamentous free-living fungi with the ability to antagonize plant-pathogenic fungi and to stimulateplant growth and defense responses. Trichoderma species are highly interactive in root, soil and foliar environments and havebeen used successfully in field trials to control many crop pathogens like Sclerotium rolfsii and Rhizoctonia solani. In thisstudy, the influence of the inoculation of six native Trichoderma strains on the growth of alfalfa and Arabidopsis thaliana andtheir action as biological protectors against pathogenic fungi were analysed. Competition assays revealed three Trichodermaspp. strains as antifungal agents against Macrophomina phaseolina and Fusarium spp. We also examined the root structure ofthe plants using the image analysis tool ARIA (Automatic Root Image Analysis), and found a significant increase in thedevelopment of secondary roots, both in arabidopsis and alfalfa, when plants were faced with the fungi in Petri dishes. Thenumber of root hairs was also larger in plants under the presence of Trichoderma, which could indicate a greater capacity touptake nutrients and water. This result could be translated into a higher biomass production of these plants, a hypothesis thatis under study.