Brassica napus Genome Possesses Extraordinary High Number of CAMTA Genes and CAMTA3 Contributes to PAMP Triggered Immunity and Resistance to Sclerotinia sclerotiorum.
Brassica napus Genome Possesses Extraordinary High Number of CAMTA Genes and CAMTA3 Contributes to PAMP Triggered Immunity and Resistance to Sclerotinia sclerotiorum.
复制标题
甘蓝型油菜基因组拥有大量 CAMTA 基因，CAMTA3 有助于 PAMP 触发免疫和对核盘菌的抗性
DOI：
10.3389/fpls.2016.00581
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发表时间：
2016
影响因子：
5.6
通讯作者：
Cai XZ
中科院分区：
文献类型：
--
作者：
Rahman H;Xu YP;Zhang XR;Cai XZ
钙调素结合转录激活因子（CAMTAs）在植物抗病、抗逆等生物学过程中发挥着重要作用。油菜（Brassica napus L.）是世界上最重要的油料作物之一。迄今为止，CAMTAs在芸苔属物种基因组中的组成以及CAMTAs在对毁灭性的坏死型真菌病原体核盘菌（Sclerotinia sclerotiorum）的抗性中的作用仍然未知。本研究通过生物信息学分析，在油菜基因组中鉴定出18个CAMTA基因，这些基因均遗传自其祖先甘蓝和芜菁的9个拷贝，是迄今为止鉴定出的最多的CAMTA基因。基因结构、蛋白质结构域组织和同源性分析表明，油菜CAMTAs与其它植物CAMTAs结构相似，可分为3大类，但在油菜形成前的蔷薇科植物中，CAMTA 3和CAMTA 4基因有独特的扩展。在BnCAMTA基因的1.5kb启动子区存在大量与胁迫反应相关的顺式元件。BnCAMTA基因在不同器官中表达差异，并对植物激素和S.以及病原菌接种。值得注意的是，BnCAMTA 3A 1和BnCAMTA 3C 1在S.表明它们在油菜与S.菌核此外，使用拟南芥camta突变体的接种分析表明，Atcamta 3突变体植物表现出比野生型和其他Atcamta突变体植物显着更小的疾病病变。此外，与野生型相比，Atcamta 3植株对PAMP几丁质的反应中积累了明显更多的过氧化氢，并表现出更高的含CGCG-box基因BAK 1和JIN 1的表达，这两个基因是PAMP触发免疫（PTI）和/或植物对病原体包括S.菌核我们的研究结果表明，CAMTA 3可能通过直接靶向BAK 1来负调控PTI，也可能通过直接靶向JIN 1来抑制JA信号通路来负调控植物防御。
Calmodulin-binding transcription activators (CAMTAs) play important roles in various plant biological processes including disease resistance and abiotic stress tolerance. Oilseed rape (Brassica napus L.) is one of the most important oil-producing crops worldwide. To date, compositon of CAMTAs in genomes of Brassica species and role of CAMTAs in resistance to the devastating necrotrophic fungal pathogen Sclerotinia sclerotiorum are still unknown. In this study, 18 CAMTA genes were identified in oilseed rape genome through bioinformatics analyses, which were inherited from the nine copies each in its progenitors Brassica rapa and Brassica oleracea and represented the highest number of CAMTAs in a given plant species identified so far. Gene structure, protein domain organization and phylogentic analyses showed that the oilseed rape CAMTAs were structurally similar and clustered into three major groups as other plant CAMTAs, but had expanded subgroups CAMTA3 and CAMTA4 genes uniquely in rosids species occurring before formation of oilseed rape. A large number of stress response-related cis-elements existed in the 1.5 kb promoter regions of the BnCAMTA genes. BnCAMTA genes were expressed differentially in various organs and in response to treatments with plant hormones and the toxin oxalic acid (OA) secreted by S. sclerotiorum as well as the pathogen inoculation. Remarkably, the expression of BnCAMTA3A1 and BnCAMTA3C1 was drastically induced in early phase of S. sclerotiorum infection, indicating their potential role in the interactions between oilseed rape and S. sclerotiorum. Furthermore, inoculation analyses using Arabidopsis camta mutants demonstrated that Atcamta3 mutant plants exhibited significantly smaller disease lesions than wild-type and other Atcamta mutant plants. In addition, compared with wild-type plants, Atcamta3 plants accumulated obviously more hydrogen peroxide in response to the PAMP chitin and exhibited much higher expression of the CGCG-box-containing genes BAK1 and JIN1, which are essential to the PAMP triggered immunity (PTI) and/or plant resistance to pathogens including S. sclerotiorum. Our results revealed that CAMTA3 negatively regulated PTI probably by directly targeting BAK1 and it also negatively regulated plant defense through suppressing JA signaling pathway probably via directly targeting JIN1.