Trichoderma spp.: a sustainable alternative to protect Arabidopsis thaliana against biotrophic and necrotrophic phytopathogens

SANTONE, A.; CAMPOS BERMUDEZ, V.A.; SPAMPINATO, CLAUDIA P.

Mendoza

Congreso; LVIII Reunión Anual SAIB; 2022

Trichoderma spp. is a filamentous fungus that inhabits the rhizosphere and beneficially interacts with plants. This interaction induces a plant systemic defense response against a high phytopathogen diversity. This response is activated from the colonization of roots by Trichoderma spp. In this study, the ability of Trichoderma spp. to protect Arabidopsis thaliana against Pseudomonas syringae , a biotrophic pathogen, and Botrytis cinerea , a necrotrophic pathogen, was evaluated. P. syringae is associated with salicylic acid (SA)-dependent defense responses and induces plant cell death at the site of infection. B. cinerea is associated with jasmonic acid (JA)-dependent defense responses that promote cell death prior to or during colonization and acquire nutrients from dead cells. In order to analyze the differential expression of defense-related genes after pathogen attack, five A. thaliana genes were selected: PR1 , PAL1 and SID2 involved in the SA pathway; VSP2 involved in the JA pathway and GLY4 that modulates the crosstalk between the SA and JA signaling pathways. First, roots from two weeks old A. thaliana plants (n=14) were inoculated with a suspension of 106 conidia/ml of Trichoderma atroviride , Trichoderma harzianum, Trichoderma virens or Trichoderma reesei . Control plants were inoculated with distilled water. After 10 days, 7 plants were infected by spraying with a P. syringae suspension (DO=2) and 7 plants weresprayed with distilled water (control plants). The same procedure was applied for B. cinerea . Leaf samples from all treatments were taken at 1 hour post infection (hpi) and 3 days post infection (dpi) and were used for P. syringae colony-forming unit (CFU) determination. No significant differences in CFU (ANOVA; p>0.005) were observed between treatments at 1 hpi. In contrast, statistical significant differences were observed between control and inoculated Trichoderma plants, being T. atroviride the species with the highest pathogen protection (p0.05) were observed between treatments at 1 hpi. PR1 , GLY4 and SID2 showed a significantly higher expression (p