Comparative and functional genomics reveals genetic diversity and determinants of host specificity among reference strains and a large collection of Chinese isolates of the phytopathogen Xanthomonas campestris pv. campestris

Table 10 Identification of the genetic determinants for host specificity of Xcc 8004 on certain plants

Candidate avr genes in Xcc 8004				Mutational analysis^†
Postulated avr gene	Gene ID	Annotated function	Correlation (CC)*	Mutant ID	Virulence	8004	Plants
avrRc1	XC2004	Avirulence protein, avrXccC	-1	NK2004	+	-	TP1
	XC2084	Tn5041 transposase	-1	...	...	...	...
avrRc3	XC2602	Avirulence protein, avrXccE1	-0.88	NK2602	+	-	TP8
avrRp1	XC2081	Avirulence protein, avrBs1 gene	1	NK2081	N	HR	TP12

*The direct correlation analysis between virulence of the 20 Xcc strains on one given plant cultivar and the distribution status of each gene in 20 Xcc strains was carried out using the program CORREL. The maximal absolute CC values were selected from Additional data file 8. ^†The mutants of the candidate genes were generated by means of pK18mob integration and the plant tests were carried out on given plants that showed specific reactions to certain Xcc strains. TP1, mustard (B. juncea var. megarrhiza Tsen et Lee) cv. Guangtou; TP8, Chinese cabbage (B. rapa subsp. pekinensis) cv. Zhongbai-83; TP12, pepper (Capsicum annuum v. latum) ECW10R. +, virulent; -, non-pathogenic. The hypersensitive reaction (HR) tests of Xcc strains were carried out on TP12. HR, positive HR result; N, no HR. ..., data unavailable.

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