Survey on soft rot and vascular necrosis of sugar beet
2003
Zohour, E.(Khorasan Agricultural and Natural Resources Research Center)
Survey on soft rot and vascular necrosis of sugar beet Soft-rot-affected sugarbeet (Beta vulgaris .L) samples were collected from different sugarbeet growing areas of from Khorasan province during growing and harvesting seasons of 2000. Pieces of the affected. specimens were triturated in distilled water and the suspensions were plated on EMB agar.Eight strains of pectolytic Erwinia were isolated, and their phenotypic characteristics and electerophoretic profiles of cell protein were compared.The strains formed two phena 75% similarity level.Phena I (26 strains) showed 77%similarity with a reference strains of pectobacterium carotovorum subsp. odoriferum (Pco).Strains of this phena differed from pectobacterium carotovorum subsp odoriferum in utilizatio of inulin, arabinos and citrate.Their similarity levels to the reference strains of P.c. subsp.betavasculorum(Pcb).P.c.subsp. atrosepticum (pca).P.c.subsp. carotovorum(Pcc),P.c.subsp.wasabiae (pc w) and P. chrysanthemi(Pch) were73,67,64.50.and 47% respectivley .subphena were present in phena I. Strains of phena II were more closely related to Pch (80% similarity), although had features intermediate between Pch.Pca ,Pcb and Pco.Their levels of similarity with the reference strains of Pcb,Pco,Pca ,Pcc , and Pcw were 66.63,60,60,and 47% respectivel .Phenon II had two subphena (at 88% similarity level) and each subphena were comprised of two phenotypically differentiated groups .Features differentrating the two subphena were methyl red reactive , sensitivity to erythomycin, production of lecithinase and utilization of inulin (By strains of subphenonI).and production of acetion and indole and utilization of gluconate (by strains of subphenon (II) from different subphena confirmed the electrophoretic profile of cell proteins of the representative strains the heterogeneity of the strains isolated from sugarbeet .The protein profile of the members of phena II were similar to , although not identical with a reference strains of P. chrysanthemum. Because of their heterogeneity and lack of close phenotypic similarity to the existing species and subspecies of the genus Pectobacterium their exact taxonomic stutus with in the genus of the strains isolated from soft rot - affected sugarbeets in Khorasan can not be established .They may represent members of as yet not described species of subspecies of Pectobacterium
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