Pectobacterium carotovorum subsp. Carotovorum: The causal agent of calla soft rot in Serbia and Montenegro

Abstract

Bacterial strains were isolated from above- and underground parts of diseased calla plants originating from different localities in Serbia and one locality in Montenegro. They were characterized by studying their pathogenic, cultural, biochemical and physiological characteristics. All investigated strains caused soft rot of calla leaf stalks, potato slices and aloe leaves, and induced hypersensitive reaction on tobacco. Bacteriological properties of the strains indicated that symptoms on calla plants were caused by Gram-negative, nonfluorescent, oxidase negative, catalase positive and facultatively anaerobic bacterium belonging to the genus Pectobacterium. The investigated strains grew at 37ºC and in 5% NaCl, utilised lactose and trechalose, and produced neither indol nor lecitinase. These results, as well as the characteristic growth on Logan's differential medium indicated that soft rot of tuber and stem base of calla plants was caused by Pectobacterium carotovorum subsp. carotovorum. This is the first report of this pathogen affecting calla plants in Serbia.

Proučene su patogene, odgajivačke i biohemijsko-fiziološke odlike sojeva izolovanih iz nadzemnih i podzemnih delova obolelih biljaka kale gajene u različitim lokalitetima u Srbiji i jednom lokalitetu u Crnoj Gori. Svi proučavani sojevi ispoljili su izraženu pektolitičku aktivnost prouzrokujući vlažnu trulež lisnih drški kale, kriški krompira, liski aloje ili sanseverije, a prouzrokovali su i hipersenzitivnu reakciju duvana. Proučavanjem bakterioloških karakteristika utvrđeno je da promene na biljkama kale prouzrokuju Gram-negativni, nefluorescentni, oksidaza-negativni, katalaza-pozitivni i fakultativno-anaerobni sojevi bakterije, koja prema navedenim karakteristikama pripada rodu Pectobacterium. Proučavani sojevi se razvijaju pri 37ºC i u prisustvu 5% NaCl, razlažu laktozu i trehalozu, ne stvaraju indol i lecitinazu. Navedeni rezultati, kao i karakterističan razvoj na Loganovoj diferencijalnoj podlozi ukazuju da je vlažnu trulež korena i prizemnog dela biljaka kale prouzrokovala bakterija Pectobacterium carotovorum subsp. carotovorum. Ovo je prvo saopštenje o pojavi P. c. ssp. carotovorum kao patogena kale u Srbiji.