Xanthomonas campestris pv. malvacearum strain XcmH1005 is the source of 6 plasmidborne avr genes that are members of the Xanthomonas avirulence (avr)/ pathogrnicity iptfit gene fa mil», but ooJ> one of these highly homologous genes âknown to affect ils palbogenkify (Yang vl aL, 19*4. MoI. PUn! Microbe Interact. 7:345-355). Stec* XcmHI005 contained sis additional DNA fragments thai h»bridi/rd Io gene fa mil» member«. lhr»e additional fragments «err ciooed, charectcnjrd. and av. ia>ed for a»iruknct and palhotcenkily functiom. Four of the MI fragmenis exhibited anmJeace fuacUoa; three arc ne« genes and one (mrrBm) b prrvionsly described bat no« rwiiuni/cd js ëmember of the Rene family. Marker-e» êu.in 1IUItJiIUMs of \cmill005 and complementation lest» revealed thai at least seten of ihr 10 XcmH 10O$ mvrfptk family members exhibited plciolrnpic palhogenic-ily (watenaaking) function on cotton, bat only fire arrfptk (MkW «ere needed for full wairrsoaUiig. Tbc contribution af «ncfa gene to palhogrnkity «as additive, and five of lhc I• err/pth genes appeared to be rrdundanl. One \cnv H1005 mulanl. in which %evrn member« of ihr gene family were eliminated, «a* asymptomatic on susceptible cotton and 1.600 times less mutant bacteria «ere released onto lhe leaf surface in comparison with the wild-type strain. However, the in planta growth rate and yield of this mu-tant on susceptible plants were identical to those of the wild type. We conclude thai pathogenictty of XcmH 1005 on cotfhn, but not growth in planta, requires multiple specific members of the \anlhomonas avrfpth gene family.
All Science Journal Classification (ASJC) codes
- Agronomy and Crop Science