Evidence for intragenic recombination and selective sweep in an effector gene of Phytophthora infestans.
Evidence for intragenic recombination and selective sweep in an effector gene of Phytophthora infestans.
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DOI：
10.1111/eva.12629
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发表时间：
2018-09
影响因子：
4.1
通讯作者：
Zhan J
中科院分区：
文献类型：
--
作者：
Yang L;Ouyang HB;Fang ZG;Zhu W;Wu EJ;Luo GH;Shang LP;Zhan J
效应器是病原菌分泌的一组小蛋白，通过调节寄主免疫系统和病原菌侵染能力的双重功能，在植物寄主与病原菌的拮抗相互作用中发挥重要作用。在这项研究中，通过对从中国地区不同温度变异和种植制度的6个地点收集的96个致病疫霉菌株产生的AVR3a序列的群体遗传分析，研究了效应基因的进化。我们发现AVR3a基因的高度遗传变异是由多种机制引起的，这些机制超出了点突变、移码和终止密码子失效的范围，导致了基因内重组。在96个全序列中共检测到51个核苷酸单倍型，编码38个氨基酸亚型，其核苷酸多样性在0.007~0.023之间(平均值为0.017)。虽然单倍型和核苷酸多样性很高，但效应基因只由三种单倍型控制。(1)单倍型的群体遗传分化(G-ST)低于SSR标记座位的群体分化(F-ST)；(2)Tajima‘s D和Fu’s FS为负值。采集点的年平均温度与毒力形式(Avr3aEM)的出现频率呈负相关，表明AVR3a可能受温度的调节。这些结果表明，全球变暖导致的气温升高可能会阻碍赤星病原虫致病特性的发展，可能需要在有限的热条件下进行进一步的研究来证实这一假说。
Effectors, a group of small proteins secreted by pathogens, play a critical role in the antagonistic interaction between plant hosts and pathogens through their dual functions in regulating host immune systems and pathogen infection capability. In this study, evolution in effector genes was investigated through population genetic analysis of Avr3a sequences generated from 96 Phytophthora infestans isolates collected from six locations representing a range of thermal variation and cropping systems in China. We found high genetic variation in the Avr3a gene resulting from diverse mechanisms extending beyond point mutations, frameshift, and defeated start and stop codons to intragenic recombination. A total of 51 nucleotide haplotypes encoding 38 amino acid isoforms were detected in the 96 full sequences with nucleotide diversity in the pathogen populations ranging from 0.007 to 0.023 (mean = 0.017). Although haplotype and nucleotide diversity were high, the effector gene was dominated by only three haplotypes. Evidence for a selective sweep was provided by (i) the population genetic differentiation (G ST) of haplotypes being lower than the population differentiation (F ST ) of SSR marker loci; and (ii) negative values of Tajima's D and Fu's FS. Annual mean temperature in the collection sites was negatively correlated with the frequency of the virulent form (Avr3aEM), indicating Avr3a may be regulated by temperature. These results suggest that elevated air temperature due to global warming may hamper the development of pathogenicity traits in P. infestans and further study under confined thermal regimes may be required to confirm the hypothesis.
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影响因子：
4.1
作者：
Gao F;Zou W;Xie L;Zhan J
通讯作者：
Zhan J
影响因子：
4.9
作者：
Allen, Rebecca L.;Meitz, Julia C.;Beynon, Jim L.
通讯作者：
Beynon, Jim L.
影响因子：
9.5
作者：
Karasov TL;Horton MW;Bergelson J
通讯作者：
Bergelson J
DOI：
10.1073/pnas.0709303105
发表时间：
2008-03-25
影响因子：
11.1
作者：
Jiang, Rays H. Y.;Tripathy, Sucheta;Tyler, Brett M.
通讯作者：
Tyler, Brett M.
影响因子：
3.2
作者：
Banta, LM;Bohne, J;Dostal, K
通讯作者：
Dostal, K