Members of the Arabidopsis HRT/RPP8 family of resistance genes confer resistance to both viral and oomycete pathogens
Members of the Arabidopsis HRT/RPP8 family of resistance genes confer resistance to both viral and oomycete pathogens
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DOI：
10.1105/tpc.12.5.663
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发表时间：
2000-05-01
期刊：
影响因子：
11.6
通讯作者：
Klessig, DF
中科院分区：
文献类型：
--
作者：
Cooley, MB;Pathirana, S;Klessig, DF
芜菁皱缩病毒（Turnipcrinklevirus，TCV）接种到抗TCV的拟南芥上，引起由显性基因HRT控制的过敏反应（hypersensitiveresponse，HR）。HRT是一类含有亮氨酸拉链、核苷酸结合位点和富含亮氨酸重复序列的抗性（R）基因的成员。HRT的染色体位置及其与抗病基因RPP 8和两个RPP 8同源物的同源性表明，不等交换和基因转换可能有助于HRT的进化。RPP 8赋予对卵菌病原体寄生霜霉（Peronospora parasitica）的抗性。尽管在HRT/RPP 8家族内有非常强的相似性，但HRT和RPP 8对它们检测的相应病原体具有特异性。因此，HRT/RPP 8家族提供的分子证据表明，多基因家族密切相关的成员之间的序列变化可以产生新的特异性，从根本上不同的病原体。表达HRT的转基因植物产生了HR，但通常仍然对TCV敏感，因为第二个基因RRT调节对TCV的抗性。然而，几个过表达HRT的转基因植物产生微HRs或没有HR时，接种TCV和抗感染。TCV外壳蛋白基因在含有HRT的幼苗中的表达导致大量坏死和死亡，表明HRT编码的蛋白质检测到的无毒因子是TCV外壳蛋白。
Turnip crinkle virus (TCV) inoculation onto TCV-resistant Arabidopsis leads to a hypersensitive response (HR) controlled by the dominant gene HRT. HRT is a member of the class of resistance (R) genes that contain a leucine zipper, a nucleotide binding site, and leucine-rich repeats. The chromosomal position of HRT and its homology to resistance gene RPP8 and two RPP8 homologs indicate that unequal crossing over and gene conversion may have contributed to HRT evolution. RPP8 confers resistance to an oomycete pathogen, Peronospora parasitica. Despite very strong similarities within the HRT/RPP8 family, HRT and RPP8 are specific for the respective pathogens they detect. Hence, the HRT/RPP8 family provides molecular evidence that sequence changes between closely related members of multigene families can generate novel specificities for radically different pathogens. Transgenic plants expressing HRT developed an HR but generally remained susceptible to TCV because of a second gene, RRT, that regulates resistance to TCV. However, several transgenic plants that overexpressed HRT produced micro-HRs or no HR when inoculated with TCV and were resistant to infection. Expression of the TCV coat protein gene in seedlings containing HRT resulted in massive necrosis and death, indicating that the avirulence factor detected by the HRT-encoded protein is the TCV coat protein.