Phylogenetic Assignment of Ralstonia pseudosolanacearum (Ralstonia solanacearum Phylotype I) Isolated from Rosa spp.

Abstract

During the last two years, greenhouse cultivation of rose (Rosa spp.) in from profiles of all other reference isolates in the RSSC included. Fur-the Netherlands has been challenged by an uncommon bacterial disease. thermore, MLP on egl, fliC, and mutS gene sequences clearly demon-Affected plants suffered from chlorosis, stunting, wilting, and necrosis. strated that all R. pseudosolanacearum isolates clustered in phylotype The bacterial isolates obtained from the different Rosa spp. cultivars were I, as a distinct monophyletic group. Interestingly, this monophyletic all identified as phylotype I, sequevar 33 from the ‘Ralstonia solanaceagroup also included phylotype I strain Rs-09-161 from eggplant (Solarum species complex’ (RSSC), actually reclassified as Ralstonia pseudonum melongena), isolated in 2009 in India. AFLP and MLP were both solanacearum. The work in this paper considers the genetic diversity and efficient in revealing the genetic divergence from the RSSC isolates in-the phylogenetic position of 129 R. pseudosolanacearum isolates from cluded. The phylogenetic tree constructed from the AFLP profiles was, the outbreak. This was assessed by AFLP based on four different in general, in agreement with the one obtained from MLP. Both phyloprimer combinations and MLP using partial sequences of the egl, mutS, genetic trees displayed a similar clustering, supported by high poste- and fliC genes. The AFLP revealed identical profiles for all the isolates, rior probabilities. Both methodologies clearly demonstrated that the irrespective of their association with Rosa sp. propagating material, R. pseudosolanacearum isolates from Rosa spp. grouped in a mono-Rosa spp. plants for cut flowers, or water used in the different greenphyletic group inside phylotype I, with a particular correspondence house cultivations. These AFLP profiles were unique and diverged to a strain present in India, as revealed in MLP.