Protective and Curative Effects of Trichoderma asperelloides Ta41 on Tomato Root Rot Caused by Rhizoctonia solani Rs33

Abstract

Two molecularly identified tomato isolates, Trichoderma asperelloides Ta41 and Rhizoctonia solani Rs33, were characterized and antagonistically evaluated. The dual culture technique showed that Ta41 had a high antagonistic activity of 83.33%, while a light microscope bioassay demonstrated that the Ta41 isolate over-parasitized the pathogen completely. Under greenhouse conditions, the application of Ta41 was able to promote tomato plant growth and had a significant increase in plant height, root length, and shoot fresh, shoot dry, root fresh, and root dry weight. It also improved chlorophyll content and total phenol content significantly, both in protective and in curative treatments. The protective treatment assay exhibited the lowest disease index (16.00%), while the curative treatment showed a disease index of 33.33%. At 20 days post-inoculation, significant increases in the relative expression levels of four defense-related genes (PR-1, PR-2, PR-3, and CHS) were observed in all Ta41-treated plants when compared with the non-treated plants. Interestingly, the plants treated with Ta41 alone showed the highest expression, with relative transcriptional levels of CHS, PR-3, PR-1, and PR-2 that were, compared with the control, 3.91-, 3.13-, 2.94-, and 2.69-fold higher, respectively, and the protective treatment showed relative transcriptional levels that were 3.50-, 3.63-, 2.39-, and 2.27-fold higher, respectively. Consequently, the ability of Ta41 to promote tomato growth, suppress Rs33 growth, and induce systemic resistance supports the incorporation of Ta41 as a potential bioagent for controlling root rot disease and increasing the productivity of crops, including tomatoes.

Trichoderma hamatum Strain Th23 Promotes Tomato Growth and Induces Systemic Resistance against Tobacco Mosaic Virus

“…Several authors have shown that the application of Trichoderma spp. was associated with an increase in root length, shoot length, and dry weight compared to the control plants [ 9 , 54 , 55 , 56 ]. Generally, the severe morphological and physiological changes including mosaic symptoms that occur upon viral infection are linked to changes in chlorophyll content and result in reduced photosynthesis [ 21 , 57 ].…”

Trichoderma spp. Genes Involved in the Biocontrol Activity Against Rhizoctonia solani

“…These findings imply that WRKY proteins, which are well-known PR gene activators, play a key role in chromatin modifications that enhance gene expression ( Mayo et al, 2016 ). PR gene expression, including enzymes, such as cellulases, glucanases, and chitinases, is engaged in direct control of R. solani and plant biochemical barrier reinforcement ( Heflish et al, 2021 ). In another study, the interaction of bean plants with R. solani resulted in the downregulation of seven defense-related genes, including chitinases ( CH5b , CH1 ), PR1 , PR2 , PR3 , PR4 , and PAL , as a mechanism to overcome the plant defense response, allowing the infection process to progress within the plant.…”

Chitosan Nanoparticles Inactivate Alfalfa Mosaic Virus Replication and Boost Innate Immunity in Nicotiana glutinosa Plants

“…Furthermore, PR-1 is a marker of the SA signaling pathway that inhibits programmed cell death, stimulates plant immunity, regulates SAR in plants, and may serve as a marker for early plant defense responses [87,88]. The accumulation and expression of PR-1 is associated with the activation of SA in response to pathogens [89]. In the present study, both treatments (p treatments < 0.0001) and time post-inoculation (p times < 0.0001) significantly affected the relative expression levels of PR-1.…”