A genetic screen reveals Arabidopsis stomatal and/or apoplastic defenses against Pseudomonas syringae pv. tomato DC3000.
A genetic screen reveals Arabidopsis stomatal and/or apoplastic defenses against Pseudomonas syringae pv. tomato DC3000.
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DOI：
10.1371/journal.ppat.1002291
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发表时间：
2011-10
期刊：
影响因子：
6.7
通讯作者：
He SY
中科院分区：
文献类型：
--
作者：
Zeng W;Brutus A;Kremer JM;Withers JC;Gao X;Jones AD;He SY
细菌对植物的感染通常始于植物表面的定植，随后通过伤口和自然开口（如气孔）进入植物，在受感染组织的细胞间隙（外质体）繁殖，并向其他植物传播细菌。从历史上看，大多数研究评估细菌感染基于疾病的最终结果和/或病原体生长使用整个感染组织；很少有研究从遗传学上区分不同宿主细胞类型对感染的反应。植物毒素冠状碱（COR）是由丁香假单胞菌的几种病原体产生的。番茄番茄番茄（Pst） DC3000的co缺陷突变体毒力严重受损，特别是接种到植株表面时。我们在这里报告了一种基因筛选，以鉴定可以挽救co缺陷突变细菌毒力的拟南芥突变体。对冠素缺乏的Pst DC3000 （scord）易感突变体中气孔关闭响应缺陷2个，外质体防御缺陷2个，气孔和外质体防御均缺陷4个。这三类突变体的分离表明，在植物中气孔和外体防御是整合的，但在遗传上是可分离的，并且COR对Pst DC3000克服气孔保护细胞和外体叶肉细胞为基础的防御很重要。在6个细菌诱导的气孔关闭缺陷突变体中，3个突变体在水杨酸（SA）诱导的气孔关闭缺陷中存在缺陷，但在脱落酸（ABA）诱导下表现出正常的气孔关闭，并且scord7在SA和ABA诱导的气孔关闭中都受到损害。我们克隆了水杨酸（SA）生物合成所需的SCORD3和编码atp结合盒（ABC）蛋白AtGCN20/AtABCF3的SCORD5，预计参与应激相关蛋白翻译控制。SCORD5的鉴定开始暗示应激相关蛋白翻译在气孔保护细胞信号传导中起重要作用，以响应微生物相关的分子模式和细菌感染。病原体进入宿主组织是引起感染的关键第一步。对于叶面细菌性植物病原体来说，气孔等自然表面开口是进入叶外质体（内部细胞间隙）的重要入口。最近的研究表明，植物对表面接种的细菌病原体的反应是通过减少气孔孔径作为先天免疫反应的一部分来限制细菌的入侵。一旦进入植物组织，细菌就会遇到外质体的防御。为了对抗宿主在入侵和外质体中的防御，细菌病原体产生多种毒力因子，如丁香假单胞菌产生的多酮毒素冠状碱。番茄（Pst） DC3000。冠状蛋白缺乏的Pst DC3000突变体在毒力上受到损害，特别是当接种到植物表面时。在本研究中，我们对拟南芥进行了随机遗传筛选，以鉴定出能够挽救冠状蛋白缺陷突变菌毒力的突变体，得到了三种类型的拟南芥突变体：仅气孔关闭缺陷突变体、仅外体防御缺陷突变体、气孔关闭和外体防御均受损突变体。这些寄主突变体的分离突出了COR的重要作用，COR是植物激素茉莉酸的分子模拟物，在Pst DC3000感染期间克服气孔和外胞体防御。
Bacterial infection of plants often begins with colonization of the plant surface, followed by entry into the plant through wounds and natural openings (such as stomata), multiplication in the intercellular space (apoplast) of the infected tissues, and dissemination of bacteria to other plants. Historically, most studies assess bacterial infection based on final outcomes of disease and/or pathogen growth using whole infected tissues; few studies have genetically distinguished the contribution of different host cell types in response to an infection. The phytotoxin coronatine (COR) is produced by several pathovars of Pseudomonas syringae. COR-deficient mutants of P. s. tomato (Pst) DC3000 are severely compromised in virulence, especially when inoculated onto the plant surface. We report here a genetic screen to identify Arabidopsis mutants that could rescue the virulence of COR-deficient mutant bacteria. Among the susceptible to coronatine-deficient Pst DC3000 (scord) mutants were two that were defective in stomatal closure response, two that were defective in apoplast defense, and four that were defective in both stomatal and apoplast defense. Isolation of these three classes of mutants suggests that stomatal and apoplastic defenses are integrated in plants, but are genetically separable, and that COR is important for Pst DC3000 to overcome both stomatal guard cell- and apoplastic mesophyll cell-based defenses. Of the six mutants defective in bacterium-triggered stomatal closure, three are defective in salicylic acid (SA)-induced stomatal closure, but exhibit normal stomatal closure in response to abscisic acid (ABA), and scord7 is compromised in both SA- and ABA-induced stomatal closure. We have cloned SCORD3, which is required for salicylic acid (SA) biosynthesis, and SCORD5, which encodes an ATP-binding cassette (ABC) protein, AtGCN20/AtABCF3, predicted to be involved in stress-associated protein translation control. Identification of SCORD5 begins to implicate an important role of stress-associated protein translation in stomatal guard cell signaling in response to microbe-associated molecular patterns and bacterial infection. Pathogen entry into host tissue is a critical first step in causing infection. For foliar bacterial plant pathogens, natural surface openings, such as stomata, are important entry sites into the leaf apoplast (internal intercellular spaces). Recent studies have shown that plants respond to surface-inoculated bacterial pathogens by reducing stomatal aperture as part of the innate immune response to restrict bacterial invasion. Once inside plant tissue, bacteria encounter defenses in the apoplast. To counter host defenses during invasion and in the apoplast, bacterial pathogens produce a variety of virulence factors, such as the polyketide toxin coronatine produced by Pseudomonas syringae pv. tomato (Pst) DC3000. Coronatine-deficient Pst DC3000 mutants are compromised in virulence, especially when inoculated onto the plant surface. In this study, we conducted a random genetic screen to identify Arabidopsis mutants that could rescue the virulence of coronatine-deficient mutant bacteria and obtained three classes of Arabidopsis mutants: those that are defective in stomatal closure only, those defective in apoplastic defense only, and those compromised in both stomatal closure and apoplastic defenses. The isolation of these host mutants highlight the important role of COR, a molecular mimic of the plant hormone jasmonate, in overcoming both stomatal and apoplastic defenses during Pst DC3000 infection.
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影响因子：
2.7
作者：
BENDER, CL;STONE, HE;COOKSEY, DA
通讯作者：
COOKSEY, DA
影响因子：
4.5
作者：
Cintas, NA;Koike, ST;Bull, CT
通讯作者：
Bull, CT
影响因子：
11.4
作者：
de Torres-Zabala, Marta;Truman, William;Grant, Murray
通讯作者：
Grant, Murray
DOI：
10.1016/0048-4059(82)90026-1
发表时间：
1982-01-01
期刊：
PHYSIOLOGICAL PLANT PATHOLOGY
影响因子：
--
作者：
MITCHELL, RE
通讯作者：
MITCHELL, RE
影响因子：
3.2
作者：
KEPPLER, LD;BAKER, CJ;ATKINSON, MM
通讯作者：
ATKINSON, MM