IDENTIFICATION OF A FAMILY OF AVIRULENCE GENES FROM XANTHOMONAS-ORYZAE PV ORYZAE
IDENTIFICATION OF A FAMILY OF AVIRULENCE GENES FROM XANTHOMONAS-ORYZAE PV ORYZAE
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DOI：
10.1094/mpmi-5-451
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发表时间：
1992-11-01
影响因子：
3.5
通讯作者：
LEACH, JE
中科院分区：
文献类型：
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作者：
HOPKINS, CM;WHITE, FF;LEACH, JE
黄单胞菌黄单胞菌小种水稻白叶枯病病原菌与水稻品种之间存在基因对基因的特异性互作。所有X菌株的多种不同大小的DNA片段。O. PV.与野油菜黄单胞菌致病变种无毒基因avrBs 3杂交，囊膜在Southern印迹中，这表明存在几个同源物，可能是一个基因家族。用PCR方法扩增了黄曲霉2号小种的基因组文库。O. PV.构建了一个对携带抗虫基因Xa-5、Xa-7和Xa-10的水稻品种无毒力的菌株。6个文库克隆，杂交avrBs 3，改变了相互作用的表型与水稻品种携带Xa-5，Xa-7，或Xa-10时，存在于一个有毒的种族6株。两个无毒基因，avrXa 7和avrXa 10，分别对应于抗性基因Xa-7和Xa-10，从杂交克隆被鉴定和部分表征。基于转座子插入突变、序列同源性、限制性酶切图谱和重复序列的存在，这两个基因都是双子叶植物黄单胞菌病原体无毒基因的同源物。与avrBs 3同源并对应于avrXa 7和avrXa 10的两个BamHI片段含有不同数量的102-bp同向重复序列的拷贝。avrXa 10的DNA序列与avrBs 3几乎相同。我们建议，avrXa 7和avrXa 10是无毒基因家族的成员，从黄单胞菌控制单双子叶植物的抗性诱导。
Races of Xanthomonas oryzae pv. oryzae, the causal agent of bacterial blight of rice, interact with cultivars of rice in a gene-for-gene specific manner. Multiple DNA fragments of various sizes from all strains of X. o. pv. oryzae hybridized with avrBs3, an avirulence gene from Xanthomonas campestris pv. vesicatoria. in Southern blots; this suggests the presence of several homologs and possibly a gene family. A genomic library of a race 2 strain of X. o. pv. oryzae, which is avirulent on rice cultivars carrying resistance genes xa-5, Xa-7, and Xa-10, was constructed. Six library clones, which hybridized to avrBs3, altered the interaction phenotype with rice cultivars carrying either xa-5, Xa-7, or Xa-10 when present in a virulent race 6 strain. Two avirulence genes, avrXa7 and avrXa10, which correspond to resistance genes Xa-7 and Xa-10, respectively, were identified and partially characterized from the hybridizing clones. On the basis of transposon insertion mutagenesis, sequence homology, restriction mapping, and the presence of a repeated sequence, both genes are homologs of avirulence genes from dicot xanthomonad pathogens. Two BamHI fragments that are homologous to avrBs3 and correspond to avrXa7 and avrXa10 contain a different number of copies of a 102-bp direct repeat. The DNA sequence of avrXa10 is nearly identical to avrBs3. We suggest that avrXa7 and avrXa10 are members of an avirulence gene family from xanthomonads that control the elicitation of resistance in mono- and dicotyledonous plants.