TaDIR1-2, a Wheat Ortholog of Lipid Transfer Protein AtDIR1 Contributes to Negative Regulation of Wheat Resistance against Puccinia striiformis f. sp. tritici.
TaDIR1-2, a Wheat Ortholog of Lipid Transfer Protein AtDIR1 Contributes to Negative Regulation of Wheat Resistance against Puccinia striiformis f. sp. tritici.
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TaDIR1-2 是脂质转移蛋白 AtDIR1 的小麦直系同源物，有助于负调控小麦对条锈菌的抗性。
DOI：
10.3389/fpls.2017.00521
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发表时间：
2017
影响因子：
5.6
通讯作者：
Kang Z
中科院分区：
文献类型：
--
作者：
Ahmed SM;Liu P;Xue Q;Ji C;Qi T;Guo J;Guo J;Kang Z
极少有LTP通过质膜受体发挥作用或参与超敏反应(HR)。DIR1是一种新型的植物LTP，在体外与脂类相互作用，在系统获得抗性(SAR)过程中转移到远距离组织，因此被认为参与了SAR过程中的远程信号转导。然而，DIR1同源基因在谷类植物中在生物和非生物胁迫下的确切功能还没有完全确定。本研究从中国小麦品种苏原11中分离到一个新的DIR1基因同源基因TaDIR1-2，并对其进行了功能鉴定。系统发育分析表明，TaDIR1-2聚在nsLTP-Type II类群中，与单子叶植物的DIR1同源基因的亲缘关系比与真双子叶植物的亲缘关系更近。TaDIR1-2定位于小麦叶肉原生质体内的细胞质和细胞膜。在小麦根、茎和叶中检测到TaDIR1-2的转录。在小麦与条锈菌的亲和互作过程中，TaDIR1-2转录本被显著诱导。小麦(PST)。水杨酸(SA)和低温处理显著上调TaDIR1-2的表达。瞬时过表达TaDIR1-2不能诱导烟草细胞死亡或抑制Bax诱导的细胞死亡。通过病毒诱导的基因沉默抑制TaDIR1-2的表达，提高了小麦对PST伴随HR的抗性，增加了H_2O_2和SA的积累，增加了TaPR1、TaPR2、TaPAL和TANOX的表达，降低了两个ROS清除基因TaCAT和TaSOD的表达。我们的结果表明，TaDIR1-2通过调节ROS和/或SA诱导的信号转导，在小麦对PST的抗性中起到负调控作用。
Very few LTPs have been shown to act through plasma membrane receptors or to be involved in the hypersensitive response (HR). DIR1, a new type of plant LTP interacts with lipids in vitro, moves to distant tissues during systemic acquired resistance (SAR) and therefore is thought to be involved in long-distance signaling during SAR. However, the exact functions of DIR1 orthologs in cereal species under biotic and abiotic stresses have not been thoroughly defined. In this study, a novel wheat ortholog of the DIR1 gene, TaDIR1-2, was isolated from Suwon11, a Chinese cultivar of wheat and functionally characterized. Phylogenetic analysis indicated that TaDIR1-2 is clustered within the nsLTP-Type II group and shows a closer relationship with DIR1 orthologs from monocots than from eudicots. TaDIR1-2 was localized in the cytoplasm and the cell membrane of wheat mesophyll protoplast. Transcription of TaDIR1-2 was detected in wheat roots, stems and leaves. TaDIR1-2 transcript was significantly induced during the compatible interaction of wheat with the stripe rust pathogen, Puccinia striiformis f. sp. tritici (Pst). Treatments with salicylic acid (SA) and low temperature significantly up-regulated the expression of TaDIR1-2. Transient overexpression of TaDIR1-2 did not induce cell death or suppress Bax-induced cell death in tobacco leaves. Knocking down the expression of TaDIR1-2 through virus-induced gene silencing increased wheat resistance to Pst accompanied by HR, increased accumulation of H2O2 and SA, increased expression of TaPR1, TaPR2, TaPAL, and TaNOX, and decreased expression of two reactive oxygen species (ROS) scavenging genes TaCAT and TaSOD. Our results suggest that TaDIR1-2 acts as a negative regulator in wheat resistance to Pst by modulating ROS and/or SA-induced signaling.