@article{fdi:010070223,
  title = {{C}omparative genomics identifies a novel conserved protein, {H}pa{T}, in proteobacterial type {III} secretion systems that do not possess the putative translocon protein {H}rp{F}},
  author = {{P}esce, {C}. and {J}acobs, {J}. {M}. and {B}erthelot, {E}. and {P}erret, {M}arion and {V}ancheva, {T}. and {B}ragard, {C}. and {K}oebnik, {R}alf},
  editor = {},
  language = {{ENG}},
  abstract = {{X}anthomonas translucens is the causal agent of bacterial leaf streak, the most common bacterial disease of wheat and barley. {T}o cause disease, most xanthomonads depend on a highly conserved type {III} secretion system, which translocates type {III} effectors into host plant cells. {M}utagenesis of the conserved type {III} secretion gene hrc{T} confirmed that the {X}. translucens type {III} secretion system is required to cause disease on the host plant barley and to trigger a non-host hypersensitive response ({HR}) in pepper leaves. {T}ype {III} effectors are delivered to the host cell by a surface appendage, the {H}rp pilus, and a translocon protein complex that inserts into the plant cell plasma membrane. {H}omologs of the {X}anthomonas {H}rp{F} protein, including {P}op{F} from {R}alstonia solanacearum and {N}ol{X} from rhizobia, are thought to act as a translocon protein. {C}omparative genomics revealed that {X}. translucens strains harbor a noncanonical hrp gene cluster, which rather shares features with type {III} secretion systems from {R}alstonia solanacearum, {P}araburkholderia andropogonis, {C}ollimonas fungivorans, and {U}liginosibacterium gangwonense than other {X}anthomonas spp. {S}urprisingly, none of these bacteria, except {R}. solanacearum, encode a homolog of the {H}rp{F} translocon. {H}ere, we aimed at identifying a candidate translocon from {X}. translucens. {N}otably, genomes from strains that lacked hrp{F}/pop{F}/nol{X} instead encode another gene, called hpa{T}, adjacent to and co-regulated with the type {III} secretion system gene cluster. {A}n insertional mutant in the {X}. translucens hpa{T} gene, which is the first gene of a twogene operon, hpa{T}-hpa{H}, was non-pathogenic on barley and did not cause the {HR} or programmed cell death in non-host pepper similar to the hrc{T} mutant. {T}he hpa{T} mutant phenotypes were partially complemented by either hpa{T} or the downstream gene, hpa{H}, which has been described as a facilitator of translocation in {X}anthomonas oryzae. {I}nterestingly, the hpa{T} mutant was also complemented by the hrp{F} gene from {X}anthomonas euvesicatoria. {T}hese findings reveal that both {H}pa{T} and {H}pa{H} contribute to the injection of type {III} effectors into plant cells.},
  keywords = {{X}anthomonas translucens ; {X}anthomonas hyacinthi ; {X}anthomonas theicola ; {C}ollimonas fungivorans ; hrp genes ; translocon ; {X}op{A} protein ; {X}op{M}},
  booktitle = {},
  journal = {{F}rontiers in {M}icrobiology},
  volume = {8},
  numero = {},
  pages = {1177 [16 ]},
  ISSN = {1664-302{X}},
  year = {2017},
  DOI = {10.3389/fmicb.2017.01177},
  URL = {https://www.documentation.ird.fr/hor/fdi:010070223},
}