Xanthomonas theicola harbours a novel type 3 secretion system

Xanthomonas theicola is the causal agent of bacterial canker on tea plants. There is no complete genome sequence available for X. theicola, a close relative of the species X. translucens and X. hyacinthi, thus limiting basic research for this group of pathogens. We optained a high quality complete genome sequence for the X. theicola type strain, CFBP 4691T using single-molecule real-time sequencing with a mean coverage of 264X. Genome mining revealed the presence of non-ribosomal peptide synthases, two CRISPR systems, the Xps type 2 secretion system, and the Hrp type 3 secretion system. Surprisingly, this strain encodes an additional type 2 secretion system and a novel type 3 secretion system with enigmatic function, hitherto undescribed for xanthomonads. Four type 3 effector genes were found on complete or partial transposons, suggesting a role of transposons in effector gene evolution and spread.

This genome sequence was obtained in the framework of an international collaboration made possible through COST Action CA16107 EuroXanth (external pagewww.euroxanth.eucall_made). It fills an important gap to better understand the biology and evolution of the early-branching xanthomonads, also known as clade-1 xanthomonads, which also harbour important forage crop pathogens such as X. translucens pv. graminis or X. t. pv. arrhenatheri.

Citation:
Koebnik R, Burokiene D, Bragard C, Chang C, Fischer-Le Saux M, Kölliker R, Lang J, Leach J, Luna E, Portier P, Sagia A, Ziegle J, Cohen SP and Jacobs J (2020) The complete genome sequence of Xanthomonas theicola, the causal agent of canker on tea plants, reveals novel secretion systems in clade-1 xanthomonads. Phytopathology®
external pagehttps://doi.org/10.1094/PHYTO-07-20-0273-SCcall_made