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Host specificity and genetic diversity of race 4 strains of R alstonia solanacearum
Author(s) -
Kumar A.,
Prameela T. P.,
Suseelabhai R.,
Siljo A.,
Anandaraj M.,
Vinatzer B. A.
Publication year - 2014
Publication title -
plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.928
H-Index - 85
eISSN - 1365-3059
pISSN - 0032-0862
DOI - 10.1111/ppa.12189
Subject(s) - biovar , biology , wilting , ralstonia solanacearum , bacterial wilt , genetic diversity , botany , multilocus sequence typing , host (biology) , genetics , genotype , gene , population , pathogen , demography , sociology
Ralstonia solanacearum race 4 isolates were obtained from Z ingiberaceae plants in India during bacterial wilt outbreaks. Polyphasic phenotypic and genotypic analysis revealed intraracial diversity and dominance of biovar 3 over biovar 4. Biovar 3 strains were isolated from very severely wilted Z ingiberaceae plants in the field and found to be present across diverse geographical, host and seasonal boundaries. It was hypothesized that these isolates belong to a single, ‘fast wilting’, lineage. Using one ‘fast wilting’ isolate in controlled inoculations, rapid wilt was observed in ginger within 5–7 days. Wilting was also observed in several other closely and distantly related hosts such as turmeric ( C urcuma longa ), aromatic turmeric ( C urcuma aromatica ), black turmeric ( C urcuma caesia ), sand ginger ( K aempferia galanga ), white turmeric ( C urcuma zeodaria ), awapuhi ( Z ingiber zerumbet ), greater galangal ( A lpinia galanga ), globba ( Globba sp.), small cardamom ( E lettaria cardamomum ) and large cardamom ( Ammomum subulatum ) of the Zingiberaceae family, and in tomato ( S olanum lycopersicum ). Molecular analysis, including multiplex PCR ‐based phylotyping, sequence analysis of 16S rDNA , 16–23 S intergenic spacer and the rec N gene, and multilocus sequence typing, revealed minimal differences between fast wilting isolates, confirming that almost all belong to the same lineage. Biovar 4 was isolated from plants showing slow wilt progression and self‐limiting wilting in restricted geographical locations instead, and was identified to be genetically distinct from the fast wilting biovar 3 isolates. To the authors' knowledge, this is the first report of host range and genetic analysis of R . solanacearum race 4 in I ndia.