AvrXa3: A novel member of avrBs3 gene family from Xanthomonas oryzae pv. oryzae has a dual function

摘要

Abstract Two positive clones pUAV45 and pUAV47 were identified from the cDNA library of Jxo III, a lace 3 strain of Xanthomonas oryzae pv. oryzae Dye (Xoo) in Japanese system, using Tn5 based technology pUAV45 clone contained a 25 4 kb Xoo ge-nomicDNAinsert Southern blot analysis with avrXa10 as the probe showed that DNA insert in pUAV45 shares homology with avrX10. Furthermore within the Xoo insert, a smaller 5. 7 kb Kpnl fragment (pUAV5k) was identified through hybridization with avrXa10. The transformation of pUAV45 and pUAV5k into the strain Pxo99 (race 6 in Philippine system) led to the decrease of Pxo99 pathogenicity on rice cultivar Wase Aikoku 3 (Xa3) and the increase of the pathogen pathogenicity on Cas209 (Xa10). The result of sequence analysis showed that there is a 2598 bp open reading frame (ORF) within the 5.7 kb Kpn1 fragment (pUAVSk). The ORF shared high identity (97%) with avrXa10. The deduced sequence of the ORF contained 8.5 tandem repeat units of 34-amino-acids, one leucine zipper (LZ), three nuclear localization signal (NLS) motifs, and an acidic activation transcriptional domain (AAD) at C-terminus We named this ORF avrXa3 and it is classified as a new member of avrBs3 (avr / pth) family with the dual-function determined byalternations of avirulence and aggressiveness on rice cultivars carrying different ' R' genes.