Molecular identification of bacterial canker and bacterial wilt diseases in tomatoes

D. Celik, O. Calis, S. Saygi

Abstract: Severe bacterial symptoms were observed in tomato growing areas of Tokat province, Turkey. The tomato plants have asymmetric wilting appearing on leaves with brown discolorations of vascular systems. A total of 45 bacterial isolates were collected from all tomato grown areas of Tokat province. A potassium hydroxide (KOH) string test was applied to all the bacterial samples: 9 of the 45 bacterial colonies were gram positive and 36 colonies were gram negative. The gram positive bacterial colonies were analyzed with Clavibacter michiganensis subsp. michiganensis specific primers Cmm5 and Cmm6 in PCR assays of which 3 produced 614 bp amplification products and were identified as C. michiganensis subsp. michiganensis. The 36 bacterial gram negative colonies were analyzed with Ralstonia ssp. specific primers RsolfliC forward and RsolfliC reverse of which 4 colonies amplified 400 bp fragments and were identified as Ralstonia ssp. Pathogenicity tests with 7 tomato cultivars and 10 wild tomato accessions revealed that all the 7 tomato cultivars were susceptible to virulent Cmm2 isolate. However, 2 wild tomato accessions (LA1054, LA1318) were resistant, 6 accessions were susceptible and 2 accessions were enhanced susceptible to the Cmm2 isolate. The results of this study demonstrated express and reliable detection methods of bacterial canker disease in tomatoes and possible resistance sources to bacterial canker disease from wild tomato accessions.

Keywords: bacterial canker; bacterial wilt; molecular diagnosis; tomato

Date published: 2019-07-26