Suppression of defense response in plants by the avrBs3/pthA gene family of Xanthomonas spp.
Suppression of defense response in plants by the avrBs3/pthA gene family of Xanthomonas spp.
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DOI：
10.1094/mpmi-19-0342
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发表时间：
2006-03-01
影响因子：
3.5
通讯作者：
Tsuyumu, S
中科院分区：
文献类型：
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作者：
Fujikawa, T;Ishihara, H;Tsuyumu, S
一些植物病原细菌的效应基因，包括来自黄单胞菌属的avrBs 3/pthA效应基因家族的一些成员，不仅赋予基因型特异性抗病性，而且赋予病原体侵袭性或毒力。此外，一些效应基因产物抑制非特异性（或一般性）过敏反应（HR）的诱导。为了确定黄单胞菌avrBs 3/pthA基因家族成员ap 11、avrXa 7或avrXa 10是否也赋予抑制剂活性，我们将具有每个效应基因的构建体引入到荧光假单胞菌55中，所述荧光假单胞菌55表达来自烟草赤星病菌的整个hrp簇。在cos-mid pHIR 11中，荧光假单胞菌（pHIR 11）接种烟草‘亮黄’后，诱导了HIN 1、RbohB、PAL和PR 1四个烟草防御反应基因的HR和表达。将含有pHIR 11和apl 1、avrXa 7、avrXa 10的荧光假单胞菌双转化体渗入烟草中，抑制了RbohB、PAL和PRI三个防御反应基因的HR和表达。HR和防御基因表达的抑制在具有apli和avrXa 7的转化体中比具有avrXa 10的转化体更有效。虽然其他防御基因的表达受到抑制的双重转化体，HIN 1的表达是相同的水平，观察后，与荧光假单胞菌（pHIR 11），表明HIN 1可能不直接参与HR。两者合计，我们的数据表明，avrXa 7，avrXa 10，apl 1，当交付给植物细胞的P.该系统可抑制非宿主HR和相关表型。
Effector genes of some plant-pathogenic bacteria, including some members of the avrBs3/pthA effector gene family from Xanthomonas spp., confer not only genotype-specific disease resistance but also pathogen aggressiveness or virulence. In addition, some effector gene products suppress induction of a nonspecific (or general) hypersensitive response (HR). To determine whether the Xanthomonas avrBs3/pthA gene family members apl1, avrXa7, or avrXa10 also confer suppressor activity, we introduced constructs with each effector gene into Pseudomonas fluorescens 55 that expressed the entire hrp cluster from P syringae pv. syringae in cos-mid pHIR11. When inoculated to tobacco 'Bright Yellow', P fluorescens (pHIR11) induces the HR and expression of four tobacco defense response genes: HIN1, RbohB, PAL, and PR1. When P fluorescens double transformants that contained pHIR11 and constructs with apl1, avrXa7, or avrXa10 were infiltrated into tobacco, the HR and expression of three defense response genes, RbohB, PAL, and PRI, were suppressed. The suppression of the HR and defense gene expression was more efficient in the transformants with the apli and avrXa7 than the transiformant with avrXa10. Although expression of other defense genes was suppressed by the double transformants, HIN1 expression was the same level as was observed after infiltration with P fluorescens (pHIR11), suggesting that HIN1 may not be involved directly in HR. Taken together, our data suggest that avrXa7, avrXa10, and apl1, when delivered to plant cells by the P. syringae pv. syringae hrp secretion system, can suppress nonhost HR and associated phenotypes.