The apoplastic secretome of Prunus persica in response to Taphrina deformans inoculation

BUTASSI, ESTEFANIA; VALENTINI, GABRIEL; DRINCOVICH, MARÍA FABIANA; LARA, MARÍA VALERIA

Salta

Congreso; LV Reunión Anual de SAIB - XIV PABMB. 2019.; 2019

Sociedad Argentina de Investigación Bioquímica y Biología Molecular

The dimorphic fungus Taphrina deformans is responsible for the ?Leaf Curl Disease? that affects Prunus persica L. trees around the world. The pathogen on the lower surface penetrates through the stomata or into the cuticle. The hyphae grow in the intercellular spaces and do not penetrate the cell. To gain insight into the molecular mechanisms involved in plant resistance to the disease, we studied apoplastic proteins differentially expressed in a resistant genotype (DR) in comparison with a susceptible one (Flavorcrest FL) during fungal infection. For this, leaves were inoculated with the fungus and collected at 0, 12, and 96 hpi (hours post-inoculation) and used for apoplastic protein isolation using the infiltration-centrifugation methodology. Proteins were analyzed by LC-ESI-MS, and differential proteins were identified using the Perseus software. In DR we identified 49 and 133 differentially expressed apoplastic proteins at 12 and 96 hpi with respect to 0 hpi, respectively. With respect to FL, 42 and 104 proteins with different levels were found at 12 and 96 hpi, respectively. The most represented functional categories of differential proteins detected in both genotypes were miscellaneous (30%), biotic and abiotic stress (27%), cell wall degradation (16.5%), protein degradation (8.5%), and signaling (5%). Regarding miscellaneous category, glucosidases, galactosidases and mannosidases, phosphatases, oxidases, GDSL-motif lipases, peroxidases, among others, were detected in both genotypes at 12 and 96 hpi. Many pathogenesis-related (PR) proteins such as beta-1,3-endoglucanases (PR2), chitinases (PR3 and PR4), thaumatin-like proteins (TLP, PR5), defensins (PR12), lipid transfer proteins (LTP, PR14) and gemin-like proteins (PR16 and PR17) were induced, mostly at 96 hpi in both genotypes. Additionally, other PRs were only induced in DR at 96 hpi, like a chitinase (M5XTV3), two TLPs (M5WTQ8 and M5WV03), a defensin (M5Y0D4), and two LTPs (M5W0V2 and M5WW86). In the cell wall degradation category, cellulases, pectinesterases, pectate lyases, polygalacturonases, and expansins were expressed in DR and FL at 12 and 96 hpi. Some of these proteins were induced only in DR at 96 hpi, such as a pectinesterase (M5VV51) and an expansin (M5XKK6). Of particular interest is the induction in the resistant genotype of proteins that are repressed or not induced in the susceptible genotype. Among these are a rapid alkalinization factor (M5WB80), a dirigent protein (M5WZH0), a gibberellin-regulated family protein (M5XFZ3), a protein with GASA domain (M5XNP6), a PR5K putative transmembrane receptor protein serine/threonine kinase (M5WA70) and a glyoxal oxidase (M5XBM0), which are currently under study. This study allowed to identify candidate resistance proteins involved in the plant pathogen response and to dissect the early molecular processes in the apoplast during the P. persica?T. deformans interaction in resistant and susceptible genotypes.