Beneficial effects of Trichoderma harzianum T-22 in tomato seedlings infected by Cucumber mosaic virus (CMV)

Abstract

The study of the biochemical and molecular mechanisms deriving from the host-pathogen-antagonist interaction is essential to understand the\ud dynamics of infectious processes and can be useful for the development of new strategies to control phytopathogens, particularly viruses, against which chemical treatments have no effect. In this work, we demonstrate the ability of the rhizospheric fungus Trichoderma harzianum strain T-22 (T22) to induce defense responses in tomato (Solanum lycopersicum var. cerasiforme) against Cucumber mosaic virus (CMV, family Bromoviridae, genus Cucumovirus) strain Fny. A granule formulation containing T22 was used for treating the plants before, simultaneously or after the CMV inoculation, in order to study the molecular and biochemical aspects of the interaction between T22 and tomato against the virus. Reactive oxygen species (ROS) and the genes encoding for ROS scavenging enzymes were investigated. Histochemical analysis revealed a different increase in the superoxide anion (O2 ) and hydrogen peroxide (H2O2) content in plants infected by CMV alone or in the presence of T22, confirming the involvement of ROS in plant defense responses. Gene expression analysis suggested a definite improvement in oxidative stress when plants were treated with T22 after inoculation with CMV. In conclusion, our data indicate that Trichoderma harzianum T-22 stimulates the induction of tomato defense responses against\ud CMV, an action that implies the involvement of ROS, pointing towards its use as a treatment rather than as a preventive measure

Sustainable Agricultural Practices in Disease Defence of Traditional Crops in Southern Italy: The Case Study of Tomato Cherry Protected by Trichoderma harzianum T-22 Against Cucumber Mosaic Virus (CMV)

“…This is because the number of fruits was not low, but they resulted in an important reduction in size, as Fig. 2 shows, accompanied by chlorotic/necrotic spots when they were ripe, confirming the observations previously made by Vitti et al (2015a). Instead, as it is possible to see in Fig.…”

“…In addition, an indication on the fact that a particular combination whereby plants first inoculated with CMV and then treated with T22 could guarantee the best control against CMV has been speculated. Finally, results obtained could also indicate an SAR-related response by the tomato plants against CMV attack, but further investigation is required to confirm these findings (Vitti et al 2015a).…”

“…In such a scenario, our work represents the starting point to improve the knowledge on the possible underlying mechanisms involved in plant-pathogen-antagonist interactions and, at the same time, to develop an innovative strategy against CMV infection in tomato plants, based on the activity of a biocontrol agent (Vitti et al 2015a).…”

“…Fourteen days after CMV inoculation (that is when the plants were at 1 month of age) and when the plants were 5 months old, leaves were collected and used for the following analyses: histochemical staining of O 2 À and H 2 O 2 in leaf discs, in order to study the involvement of ROS and total RNA extraction from leaf tissues followed by reverse transcription polymerase chain reaction (RT-PCR) analysis, for the verification of the presence of CMV in tomato seedlings, or by real-time reverse transcription PCR (qRT-PCR), in order to analyse the transcript levels of the genes implicated in plant defence, such as genes encoding for antioxidant enzymes and for pathogenesis-related protein (Vitti et al 2015a). In addition, here we report the yield evaluation for each experimental condition, determined since plants started to produce flowers and fruits (3 months of age) and until plants were 5 months old.…”

The impact of microbes in the orchestration of plants’ resistance to biotic stress: a disease management approach

“…T. harzianum primed the activation and expression of the defense genes for jasmonic acid, ethylene, and salicylic acid production in the tomato plants. It enhanced the growth of the plant, photosynthetic rate/chlorophyll content as well as the gaseous exchange capacity of the inoculated plant (Vitti et al, 2015) providing a suitable alternative to the control of viral pathogen as chemical treatment of plants is ineffective in the control of viral pathogen (Vitti et al 2015). The saprotrophic beneficial endophytic fungus T. harzianum T-78 via its efficient root colonization of tomato plant not only stop the penetration/invasion and multiplication of Meloidogyne incognita but also primed the activation of salicylic and jasmonic acid immune dependent signaling pathways in plant.…”