Overexpression of a Wheat CCaMK Gene Reduces ABA Sensitivity of Arabidopsis thaliana During Seed Germination and Seedling Growth
Overexpression of a Wheat CCaMK Gene Reduces ABA Sensitivity of Arabidopsis thaliana During Seed Germination and Seedling Growth
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小麦 CCaMK 基因的过度表达降低拟南芥种子萌发和幼苗生长过程中的 ABA 敏感性
DOI：
10.1007/s11105-010-0275-0
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发表时间：
2011-09-01
影响因子：
2.1
通讯作者：
Mao, Long
中科院分区：
文献类型：
--
作者：
Yang, Cui;Li, Aili;Mao, Long
脱落酸（阿坝）在植物生物和非生物胁迫应答中起着重要作用，钙离子是其中重要的第二信使。钙/钙调素依赖性蛋白激酶（CCaMK）是豆科植物光合作用的重要调控因子，但它是否能感知非生物胁迫下的钙信号尚不清楚，尤其是在非豆科植物中。本文报道了小麦CCaMK基因TaCCaMK的D基因组拷贝的分离和鉴定。TaCCaMK主要在小麦幼苗的根组织中表达，其蛋白质定位于细胞质膜和细胞核中，与洋葱表皮细胞一样。实时定量逆转录聚合酶链反应（qRT-PCR）结果表明，阿坝、NaCl和PEG处理均下调TaCCaMK的表达。利用热不对称交错PCR（TAIL-PCR）技术，从TaCCaMK基因起始密码子上游1,119 bp的DNA片段（pTaCCaMK）中扩增出6个ABA反应性顺式元件。pTaCCaMK可以驱动GUS报告基因在转基因拟南芥植物的根和茎中的表达，这可以被阿坝处理抑制，与小麦中qRT-PCR测定中的观察结果一致。在拟南芥中过表达TaCCaMK降低了种子萌发和根伸长过程中阿坝处理的敏感性。在高盐条件下，转基因植物也赋予增强的种子发芽率，并成为高敏感性与增加褪绿。因此，我们的数据表明，TaCCaMK是一个负调节阿坝信号可能参与小麦非生物胁迫反应。
Abscisic acid (ABA) plays pivotal roles in plant biotic and abiotic stress responses, where calcium ions are important second messengers. Calcium/calmodulin-dependent protein kinase (CCaMK) is essential for nodulation in legumes, but whether it will perceive calcium signals from abiotic stresses is not clear, especially in non-legume plants. Here we report the isolation and characterization of the D-genome copy of wheat CCaMK gene TaCCaMK. TaCCaMK was predominantly expressed in root tissues of wheat seedlings, and its proteins were located both on the cytoplasm membrane and in the nucleus as shown in the onion epidermis cells. Quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR) assay showed that the expression of TaCCaMK was downregulated by ABA, as well as NaCl and PEG treatments in wheat seedling roots. A DNA fragment of 1,119 bp upstream of the start codon of the TaCCaMK gene (pTaCCaMK) was isolated by thermal asymmetric interlaced PCR (TAIL-PCR), on which six ABA-responsive cis-elements were predicted. pTaCCaMK can drive GUS reporter gene expression in the root and stem stalk of the transgenic Arabidopsis plants which can be repressed by ABA treatments, consistent with the observation in the qRT-PCR assay in wheat. Overexpressing TaCCaMK in Arabidopsis plants reduced their sensitivity to ABA treatment during seed germination and root elongation. Under high-salt conditions, the transgenic plants also conferred enhanced seed germination rate and became hypersensitive with increased chlorosis. Therefore, our data suggest that TaCCaMK is a negative regulator for ABA signaling which may participate in abiotic stress responses in wheat.