Functional analysis of African Xanthomonas oryzae pv. oryzae TALomes reveals a new susceptibility gene in bacterial leaf blight of rice.
Functional analysis of African Xanthomonas oryzae pv. oryzae TALomes reveals a new susceptibility gene in bacterial leaf blight of rice.
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DOI：
10.1371/journal.ppat.1007092
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发表时间：
2018-06
期刊：
影响因子：
6.7
通讯作者：
Szurek B
中科院分区：
文献类型：
--
作者：
Tran TT;Pérez-Quintero AL;Wonni I;Carpenter SCD;Yu Y;Wang L;Leach JE;Verdier V;Cunnac S;Bogdanove AJ;Koebnik R;Hutin M;Szurek B
大多数黄单胞菌属物种将转录激活子样（TAL）效应子转运到植物细胞中，在那里它们通过可编程的DNA结合结构域而像植物转录因子一样起作用。对水稻致病性X. oryzaepv.水稻含有9-16个不同的Tal效应基因，但其中只有几个的功能已被破译。利用全基因组测序，我们首先对形成不同于亚洲Xoo的非洲遗传谱系的三个Xoo菌株中的TAL效应子的完整库进行了比较分析，在此称为TAL组。对3个TALomes基因的系统发育分析和TAL效应子靶标的计算机模拟预测表明，非洲白叶枯病菌TALomes基因高度保守，与亚洲白叶枯病菌TALomes基因遗传距离较远，与细菌性条斑病菌Xanthomonas oryzae pv的TAL效应子亲缘关系较近。稻生菌属（Xoc）。在三个TAL组中可以识别出九个TAL效应子簇，其中三个在其重复可变双残基（RVD）中显示出较高水平的变异。对这些组的详细分析揭示了重组事件是TAL效应基因变异的可能来源。接下来，为了阐明对毒力的贡献，在TAL效应子缺陷型X.A.2.1中表达了来自马里Xoo株系MAI 1的9个TAL效应子基因和来自布基纳法索Xoo株系BAI 3的4个等位基因变体，从而代表了非洲Xoo株系中的大多数TAL效应子多样性。米菌株X11-5A进行功能获得试验。通过对感病水稻品种Azucena的接种，发现了3个促进致病性的TAL效应子，包括先前报道的2个靶向感病基因OsSWEET 14的TAL效应子和一个新的主要致病性贡献者TalB。在水稻中进行RNA谱分析实验和EBE的计算机模拟预测，以鉴定TalB的候选靶标，揭示了OsTFX 1，一种先前鉴定为细菌性枯萎病S基因的bZIP转录因子，和OsERF#123，其编码亚组IXc AP 2/ERF转录因子。设计的TAL效应子的使用表明，任一基因的诱导导致对菌株X11-5A的更高敏感性。BAI 3 Δ1是BAI 3的talB敲除衍生物，携带这些设计的TAL效应子，对OsERF#123的诱导增加了BAI 3 Δ1的毒力，验证了OsERF#123是一个新的细菌性枯萎病S基因。大多数黄单胞菌属植物病原细菌感染其宿主的能力依赖于被称为TAL效应子的特定蛋白家族的作用，TAL效应子是由细菌注射到植物中的转录激活子。TAL效应子进入植物细胞核并结合到特定植物基因的启动子上。当被诱导时能够有益于病原体增殖或疾病发展的基因被称为易感性（S）基因。在此，我们对三株X. oryzaepv.稻，其引起水稻的细菌性叶枯病，这是这种主要作物的主要产量限制。通过全基因组测序，我们比较了三个非洲Xoo毒株的TAL效应子的大库，这三个毒株形成了不同于亚洲毒株的遗传谱系。我们评估了三个菌株中代表的13种TAL效应子变体对病原体毒力的个体贡献，并鉴定了一种主要贡献。通过结合宿主转录组分析和TAL效应子结合位点预测，我们鉴定了该TAL效应子的两个靶点，一个是先前鉴定的，一个是新的S基因，它们作为S基因发挥功能。我们使用设计的TAL效应器通过功能表征验证了新的S基因。两个S基因都编码转录因子，因此可被认为是病原体操纵宿主转录组的易感性枢纽。我们的研究结果为TAL效应子在植物病害中的作用提供了新的视角。
Most Xanthomonas species translocate Transcription Activator-Like (TAL) effectors into plant cells where they function like plant transcription factors via a programmable DNA-binding domain. Characterized strains of rice pathogenic X. oryzae pv. oryzae harbor 9–16 different tal effector genes, but the function of only a few of them has been decoded. Using sequencing of entire genomes, we first performed comparative analyses of the complete repertoires of TAL effectors, herein referred to as TALomes, in three Xoo strains forming an African genetic lineage different from Asian Xoo. A phylogenetic analysis of the three TALomes combined with in silico predictions of TAL effector targets showed that African Xoo TALomes are highly conserved, genetically distant from Asian ones, and closely related to TAL effectors from the bacterial leaf streak pathogen Xanthomonas oryzae pv. oryzicola (Xoc). Nine clusters of TAL effectors could be identified among the three TALomes, including three showing higher levels of variation in their repeat variable diresidues (RVDs). Detailed analyses of these groups revealed recombination events as a possible source of variation among TAL effector genes. Next, to address contribution to virulence, nine TAL effector genes from the Malian Xoo strain MAI1 and four allelic variants from the Burkinabe Xoo strain BAI3, thus representing most of the TAL effector diversity in African Xoo strains, were expressed in the TAL effector-deficient X. oryzae strain X11-5A for gain-of-function assays. Inoculation of the susceptible rice variety Azucena lead to the discovery of three TAL effectors promoting virulence, including two TAL effectors previously reported to target the susceptibility (S) gene OsSWEET14 and a novel major virulence contributor, TalB. RNA profiling experiments in rice and in silico prediction of EBEs were carried out to identify candidate targets of TalB, revealing OsTFX1, a bZIP transcription factor previously identified as a bacterial blight S gene, and OsERF#123, which encodes a subgroup IXc AP2/ERF transcription factor. Use of designer TAL effectors demonstrated that induction of either gene resulted in greater susceptibility to strain X11-5A. The induction of OsERF#123 by BAI3Δ1, a talB knockout derivative of BAI3, carrying these designer TAL effectors increased virulence of BAI3Δ1, validating OsERF#123 as a new, bacterial blight S gene. The ability of most Xanthomonas plant pathogenic bacteria to infect their hosts relies on the action of a specific family of proteins called TAL effectors, which are transcriptional activators injected into the plant by the bacteria. TAL effectors enter the plant cell nucleus and bind to the promoters of specific plant genes. Genes that when induced can benefit pathogen multiplication or disease development are called susceptibility (S) genes. Here, we perform a comparative analysis of the TAL effector repertoires of three strains of X. oryzae pv. oryzae, which causes bacterial leaf blight of rice, a major yield constraint in this staple crop. Using sequencing of entire genomes, we compared the large repertoires of TAL effectors in three African Xoo strains which form a genetic lineage distinct from Asian strains. We assessed the individual contribution to pathogen virulence of 13 TAL effector variants represented in the three strains, and identified one that makes a major contribution. By combining host transcriptome profiling and TAL effector binding sites prediction, we identified two targets of this TAL effector that function as S genes, one previously identified, and one, new S gene. We validated the new S gene by functional characterization using designer TAL effectors. Both S genes encode transcription factors and can therefore be considered as susceptibility hubs for pathogen manipulation of the host transcriptome. Our results provide new insights into the diversified strategies underlying the roles of TAL effectors in promoting plant disease.
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影响因子：
13.8
作者：
Blanvillain-Baufumé S;Reschke M;Solé M;Auguy F;Doucoure H;Szurek B;Meynard D;Portefaix M;Cunnac S;Guiderdoni E;Boch J;Koebnik R
通讯作者：
Koebnik R
影响因子：
2.7
作者：
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通讯作者：
Bond JE
影响因子：
4.6
作者：
Grau J;Reschke M;Erkes A;Streubel J;Morgan RD;Wilson GG;Koebnik R;Boch J
通讯作者：
Boch J
影响因子：
12.3
作者：
Gentleman RC;Carey VJ;Bates DM;Bolstad B;Dettling M;Dudoit S;Ellis B;Gautier L;Ge Y;Gentry J;Hornik K;Hothorn T;Huber W;Iacus S;Irizarry R;Leisch F;Li C;Maechler M;Rossini AJ;Sawitzki G;Smith C;Smyth G;Tierney L;Yang JY;Zhang J
通讯作者：
Zhang J
影响因子：
64.8
作者：
Gu, KY;Yang, B;Yin, ZC
通讯作者：
Yin, ZC