Trichoderma asperellum modulates defense genes and potentiates gas exchanges in upland rice plants

Abstract

Magnaporthe oryzae (Mo) damages rice leaf, and Thichoderma asperellum (Ta) is a potential biological agent against rice blast. The aims were to identify a reduction of leaf blast severity (LBS), induction of biochemical defense, growth promotion, physiological changes, and modulation of four genes, promoted by four Ta isolates and Ta pool (mixed four Ta isolates). Assay 1 (A1) tested Ta, applied by soil drenched (D) or foliar spraying (S), and evaluated LBS and enzyme activity after challenge inoculation (ChI). Assay 2 (A2) detected growth promotion and physiological changes (A, E, gs, and WUE) when Ta was applied by seed treatment (ST). In assay 3 (A3), plants were treated with Ta by D and S and evaluated after ChI for physiological changes, total chlorophyll content, antioxidant enzymes, and gene expression. In A1, all treatments suppressed leaf blast, and Ta (Ufra.T06) promoted CHI, GLU, LOX, and PAL activities in all applications form. In A2, the Ta pool promoted increases of 52%, 12,24%, 90%, and 40% in A, E, gs, and WUE, respectively. In A3, the Ta pool suppressed LBS by 89% and modulated J10sPR10 and LOX-RLL expression by increasing 35% and 474%, respectively. Ta pool is a stable combination for a multiple function biological agent and should be inserted in integrated rice management.