The Ralstonia solanacearum group, encompassing the causative agents of bacterial wilt diseases, is a highly heterogeneous species complex composed of four genospecies, or phylotypes.
More...The Ralstonia solanacearum group, encompassing the causative agents of bacterial wilt diseases, is a highly heterogeneous species complex composed of four genospecies, or phylotypes. The comparative analysis of 29 complete genome sequences using three different methods and protein profiling of a larger set of 74 bacterial strains through Matrix-Assisted Laser Desorption/Ionization-Time of Flight Mass Spectrometry (MALDI-TOF-MS) revealed that the diversity within this group warrants division into three species, consistent with recent literature. We therefore propose the acknowledgement of two new species based on genomic and proteomic data and significant biological differences: Ralstonia sequeirae sp. nov. (se.que.i’ra.e. N.L. masc. gen. n. sequeirae, of Sequeira, named after Luis Sequeira), corresponding to phylotypes I and III, with the type strain GMI1000T (=CFPB6924T =ATCC BAA-1114 T); and Ralstonia syzygii, corresponding to phylotype IV. Based on differences in pathological phenotype, R. syzygii can be further divided into three subspecies. The broad host-range soil-borne strains should be renamed R. syzygii subspecies haywardii subsp. nov. (hay.war’di.i. N.L. masc. gen. n. haywardii, of Hayward, named after A. Christopher Hayward) with the type strain UQRS464T (=PSI07T =LMG27703T =CFBP7288T). The unclassified banana Blood Disease Bacterium should be named R. syzygii subspecies celebensis subsp. nov., type strain R229T (=NCPP3726T =ICMP10001T). R. syzygii, which causes Sumatra disease in cloves, should be renamed R. syzygii subspecies syzygii subsp. nov., type strain R001T (=NCPPB3446T =LMG10661T). Moreover, phylotype II strains (from the Americas), which include the species type strain K60T (=ATCC11696T =LMG2299T), should remain in R. solanacearum.
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