Phosphite applications induce molecular modifications in potato tuber periderm and cortex enhancing resistance to Fusarium solani.

OLIVIERI F. P.; FELDMAN ML; MACHINANDIARENA MF; LOBATO M. C.; CALDIZ D.O.; DALEO G.R.; ANDREU A.B

CROP PROTECTION

ELSEVIER SCI LTD

Lugar: Netherlans; Año: 2010

0261-2194

Phosphite (Phi) compounds are salts derived from phosphorous acid which have the ability to protect plants against different pathogens. The aim of the present research was to assess the effect of Phi compounds over components of potato tuber periderm and cortex and their effects upon pathogen resistance in postharvest. In a series of field experiments potassium phosphite (KPhi) were applied to seed potato tubers and foliage and after harvest several variables were analyzed in tubers proceeding from these plants. An increase in pectin content in both, periderm and cortex tissue was observed in tubers coming from KPhi treated plants. Besides, after wounding and infection with F. solani, a high pectin accumulation in cortex tissue was also observed only in tubers coming from KPhi treated plants. Content and/or activity of polygalacturonase and proteinase inhibitor also increased in tubers from KPhi treated plants. These proteins inhibit pathogen hydrolases and therefore may participate in resistance mechanism induced at the level of external tuber tissues. Finally, a new isoform of chitinase was detected in tuber periderm coming from treated plants. These results suggest that KPhi applied to seed tuber and foliage induces resistance reactions in tuber periderm and cortex, associated with structural and biochemical changes.