Symbiotic associations in the rhizosphere. Metabolite exchange and gene expression regulation

CABANELLAS, F.; OLDRÁ, M.B.; VARGAS, W.A.

Mar del Plata

Congreso; LI Reunion Anual de SAIB; 2015

Sociedad Argentina de Investigación en Bioquimica y Biología Molecular

Trichoderma species are soil borne fungi able to establish a symbiotic association with plant roots or execute biological control of pathogenic fungi. Functional studies using the model strain Trichoderma virens, revealed the importance of plant-produced sucrose as a key player in the control of the symbiotic association. Particularly, previous studies showed that a mutant T. virens strain, impaired in the expression of an intracellular invertase (tvinv), displays five times greater root colonization rate than wild type strain. To further investigate the role of plant metabolites during the symbiotic association, we sought to compare the differential effect of sucrose on wild type and a tvinv knock out strain. When comparing protein patterns (SDS-PAGE) in culture filtrates, we detected five differential bands identified as a bifunctional catalase-peroxidase, transaldolase, 6-phosphogluconate dehydrogenase and two unknown proteins. The differential expression was further confirmed through activity assays and/or RT-qPCR. Importantly, similar correlations were also found when fungal mycelium was inoculated to A. thaliana roots in hydroponic systems. These results confirmed the importance of sucrose metabolism inside fungal cells for gene expression regulation during host colonization, including a peroxidase likely involved in ROS detoxification or cell wall degradation.