Giulia De Lorenzo

Can Phaseolus PGIP inhibit pectic enzymes from microbes and plants

Abstract The effect of a polygalacturonase-inhibiting protein (PGIP) isolated from Phaseolus vulgaris on the activities of pectic enzymes of microbial and plant origin was investigated. The PGIP inhibited all fungal endopolygalacturonases tested, but did not inhibit the activity of a bacterial endopolygalacturonase and a bacterial endopectate lyase. The protein was also unable to inhibit tomato endopolygalacturonase and exopolygalacturonases from water oak and sorghum pollen. Surprisingly, the protein inhibited exopolygalacturonase from corn pollen.

Host-pathogen interactions. XXXVII. Abilities of the Polygalacturonase-inhibiting proteins from four cultivars of Phaseolus vulgaris to inhibit the endopolygalacturonases from three races of Colletotrichum lindemuthianum ☆

Abstract The ability of endo polygalacturonases isolated from three races of Colletotrichum lindemuthianum to form phytoalexin elicitor-active oligogalacturonides was studied in the absence and presence of endo polygalacturonase-inhibiting proteins (PGIPs) isolated from four varieties of Phaseolus vulgaris . Endo polygalacturonases (each 40 kDa on SDS-PAGE) from the α, β, and γ races of Colletotrichum lindemuthianum were purified by ion-exchange and fast-protein-liquid gel-permeation chromatographies. The polygalacturonases from the three races formed elicitor-active oligogalacturonides at the same rate. PGIPs (each 41 kDa) were purified from four different cultivars of Phaseolus vulgaris (cvs Great Northern, Pinto, Red Kidney, and Small Red) by affinity chromatography through a Sepharose- endo polygalacturonase column. The PGIPs from all four cvs of P. vulgaris were able to increase the lifetimes of phytoalexin elicitor-active oligogalacturonides generated by the endo polygalacturonases. We observed no significant differences in the rate and pattern of formation of elicitor-active oligogalacturonides by the three enzymes in the presence of each of the four PGIPs. Our data indicate that the interaction between endo polygalacturonases and their inhibitor proteins does not per se explain race-cultivar specificity.

Polygalacturonase-Inhibiting Proteins (PGIPs): Their Role in Specificity and Defense against Pathogenic Fungi

Plants are continually exposed to a vast array of potential fungal pathogens; in many cases, they resist attack by blocking fungal development soon after penetration. Because plants lack a circulatory system and antibodies, they have evolved a defense strategy by which each cell is capable of defending itself by means of a combination of constitutive mechanisms and induced responses. After the perception of the pathogen (recognition), the plant cell at the site of infection transmits the information inside the cell across the plasma membrane as well as to neighboring cells. Consequently, a number of defense reactions are induced, the effectiveness of which lies both in the magnitude and the rapidity of their onset.1

Large-scale proteome analysis of tomato fruit microsomes

Resumen del poster presentado al 36th FEBS Congress celebrado en Torino (Italia) del 25 al 30 de Junio de 2011.-- et al.