Pectin Relations of Sclerotinia cinerea

Abstract

The pectic substances which constitute the middle lamellae of fleshy fruits, and thus serve as the cementing material between cells, are of great interest to the plant pathologist because of the fact that if an invading organism is to make its way into a tissue, it must either pass along the line of the middle lamella between the cells, or it must bore through the cells. In the first case a pectic enzyme at the hands of the parasite may be presupposed, and in the second case a cellulose enzyme.The mechanism of infection by Sclerotinia cinerea has received particular attention recently by Cooley (4) and by Valleau (8).Cooley maintains that its hyphae in plum tissue are mainly intracellular; while Valleau finds them to be entirely intercellular, and produces photomicrographs to prove it. Cooley could not demonstrate the presence of an enzyme which would dissolve the calcium pectate of the middle lamella. He also failed to find

Brown Rot Strikes Prunus Fruit: An Ancient Fight Almost Always Lost

“…In this material, the maturity date of seedlings correlated negatively with their BR resistance (late-maturing individuals appeared as less resistant); however, using a multiple QTL model including maturity date as a covariate phenotype, significant genotype–phenotype associations were found between skin resistance and both M1a and EPPISF032 SSR markers (located in the LG2 and LG4 of Prunus genome, respectively). Additionally, flesh resistance was correlated with SNPs located in LG3 of peach genome, confirming the previously reported independence between genetically controlled mechanisms for skin and flesh resistance …”

“…Additionally, flesh resistance was correlated with SNPs located in LG3 of peach genome, confirming the previously reported independence between genetically controlled mechanisms for skin and flesh resistance. 132 Despite the different results obtained in these two studies, probably due to differences in the different genetic background of the studied populations, the pathogenic agent employed, and the different phenotyping approaches, they contribute to the literature regarding the identification of potentially useful genetic markers for assisted selection of new cultivars with enhanced BR resistance.…”

“…Endopolygalacturonase and pectin esterase activities generate low molecular weight metabolites. , These secretions cause the collapse of the affected host cell. ,, Willaman suggested that a hydrophilic gel of calcium pectate is formed from pectin degraded by M. fructicola.…”

Hydrolysis of Pectin by Various Micoörganisms

“…The effect of Sclerotinia and Monilia on pectin was studied by Willaman (10) and by Davison and Willaman, (2) who state that Sclerotinia secretes an enzyme, pectase, which attacks pectin. Davison and Willaman follow the recommendation of the pectin nomenclature committee of the American Chemical Society in recognizing three enzymes that attack pectin compounds.…”