Allelic profile of Serbian Xanthomonas campestris pv. campestris isolates from cabbage

Abstract

Xanthomonas campestris pv. campestris (Xcc), the causal agent of black rot disease of cabbage (Brassica oleracea var. capitata L.), is one of the most important bacteria which affect proper cabbage growth, leading to head weight and quality losses and thereby drastically reducing its marketing value. The pathogen is genetically diverse, which is evident from the presence of eleven races worldwide and more than thirty combinations of allelic profiles. Therefore, this study aimed to determine the allelic profiles of Serbian cabbage Xcc strains obtained in 2014. The analysis was done on three selected Xcc strains whose DNA was first amplified using polymerase chain reaction (PCR) with four housekeeping genes - P-XdnaK, fyuA, gyrB, and rpoD, then sequenced, and the obtained sequences were finally used to determine allelic profiles. Allelic profiles were determined by comparison with 33 Xcc strains obtained from different hosts and regions, whose allelic profiles had been determined previously. A non-redundant database (NRDB) from the pubMLST was used for allelic profile determination and Phyloviz software for constructing a minimum spanning tree. The obtained allelic profile of all Serbian Xcc cabbage strains was 1, 3, 1, 1 for the P-X-dnaK, fyuA, gyrB and rpoD genes, respectively. This profile is assigned as sequence type 2 (ST2) and it coincides with a Portuguese B. oleracea Xcc strain, CPBF 213, originating from B. oleracea var. costata. No connection between sequence type (ST) and the host was detected.

Xanthomonas campestris pv. campestris (Xcc), prouzrokovač crne truleži kupusa (Brassica oleracea var. capitata L.) svrstava se među najvažnije fitopatogene bakterije koje utiču na pravilno razviće kupusa, dovodeći do gubitka težine glavice i njenog kvaliteta i na taj način drastično smanjuje njegovu ekonomsku vrednost. Ovaj patogen je genetički heterogen, što se ogleda kroz prisustvo dokazanih jedanaest rasa i više od trideset kombinacija alelskih profila širom sveta. Zbog svega navedenog, cilj ovog rada je determinacija alelskih profila Xcc sojeva poreklom sa kupusa prikupljenih 2014. godine. Analiza je vršena kod tri reprezentativna Xcc soja čija je DNK amplifikovana primenom lančane reakcije polimeraze (PCR) sa četiri konzervativna gena - dnaK, fyuA, gyrB i rpoD, a zatim sekvencirana i korišćena za determinaciju alelskih profila. Alelski profili su određivani poređenjem sa 33 Xcc soja izolovana sa različitih domaćina i regiona, čiji su alelski profili prethodno utvrđeni. Nonredundant baza podataka (NRDB) od pubMLST je korišćena za determinaciju alaleskih profila, a Phyloviz softver za konstrukciju Minimum Spanning stabla. Dobijeni alelski profil za sve Xcc sojeve sa kupusa iz Srbije je 1, 3, 1, 1 za gene dnaK, fyuA, gyrB i rpoD, redom. Ovaj profil je označen kao tip sekvence 2 (ST2) i podudara se sa portugalskim B. oleracea Xcc sojem CPBF 213 poreklom sa B. oleracea var. costata. Veza između tipa sekvence (ST) i biljke domaćina nije pronađena.