Cross pathogenicity, host range and molecular characteristics of <i>Fusarium oxysporum</i> species complex populations isolated from tobacco in Jilin Province, China

Abstract Fusarium wilt of tobacco (FWT) is a globally significant disease responsible for major losses in tobacco yield and quality. A total of 320 Fusarium oxysporum species complex (FOSC) isolates derived from five tobacco‐growing regions in Jilin province, China, have been confirmed as the predominant pathogens causing FWT, including F . tobaccum , F . cugenangense , F . odoratissimum and F . foetens . In this study, the results indicated that differences in the virulence of the representative isolates from tobacco from the same Fusarium species were significant. Aside from infecting tobacco, the virulence of these representative FOSC isolates differed on chilli and other crops, and they were not pathogenic or were weakly pathogenic to a further 20 crops. Six strains of formae speciales (ff. sp.) of F . oxysporum had the strongest virulence on their original hosts and were not or weakly pathogenic to tobacco. Joint analysis of the pg1 ‐ pg5 ‐ pgx1 ‐ pgx4 genes indicated that 21 isolates of F . cugenangense were divided into four branches, which were clustered with different ff. sp. of F . oxysporum ; five isolates of F . foetens were clustered in a branch with f. sp. fragariae , which were not pathogenic to strawberries; six isolates of F . tobaccum and five isolates of F . odoratissimum comprised independent branches and did not cluster with any other f. sp. of F . oxysporum . In sum, none of the FOSC isolates causing FWT in Jilin exhibited tobacco specificity. Our findings further confirmed that FOSC isolates from tobacco could be distinguished into F . tobaccum , F . cugenangense , F . odoratissimum and F . foetens .