Apoplastic hydrophobic proteins involved in tuber defense response to P. infestan

FERNANDEZ, MARIA BELEN; DALEO, G.; GUEVARA, MG; PAGANO, MARIANA

San Miguel de Tucuman, Argentina

Congreso; XLV Reunión Anual de la SAIB.; 2009

Asociacion Argentina de Bioquimica y Biologia Molecular

During infection, oomycetes secrete effectors into the plant apoplast where they interact with host resistance proteins. In response, large amounts of protease and protease inhibitors (Pis), are accumulated. We analyzed Apoplastic Hydrophobic differentially expressed Proteins (AHPs) in potato tubers from Innovator (resistant) and Spunta (susceptible) cvs, after wounding and P. infestans infection. Intercellular washing fluid was extracted from control, wounded or infected tubers at 0 24 and 48h and chromatographed into a PepRPCtm HR5/5 in FPLC. After elution with acetonitrile, fractions were analyzed by SDS-PAGE and proteins identified by MALDI-TOF-MS. Innovator cv. showed a higher basal AHP content and hydrophobicity than Spunta cv. In the latter, infection induced accumulation of patatins and PIs, whereas in Innovator cv. no changes in PIs accumulation were observed. A lypoxigenase, enolase, annexin p34 and glutarredoxin/cyclophilin also accumulated in response to P. infestans infection in both cvs. AHPs hydrophobicity was higher after 24h of wounding and infection in both cultivars. These results suggest that an increase in AHPs concentration would be related with the protection against the oomycete and with the degree of resistance to pathogens. Finally, changes in IPs hydrophobicity may induce changes in protease inhibitor interaction affecting the defense response.