Stress-induced co-expression of two alternative oxidase (VuAox1 and 2b) genes in Vigna unguiculata
Stress-induced co-expression of two alternative oxidase (VuAox1 and 2b) genes in Vigna unguiculata
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DOI：
10.1016/j.jplph.2009.11.001
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发表时间：
2010-01-01
影响因子：
4.3
通讯作者：
de Melo, Dirce Fernandes
中科院分区：
文献类型：
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作者：
Costa, Jose Helio;Mota, Erika Freitas;de Melo, Dirce Fernandes
豇豆（Vigna unguiculata）交替氧化酶是由一个多基因小家族（Aox 1、2a和26）编码的，该家族与大豆Aox家族是直交的。与大多数已鉴定的植物AOX基因一样。VuAox 1和VuAox 2由4个外显子和3个内含子组成。同源性分析表明，Aox基因的外显子和内含子变异具有高度的一致性，这在Aox 1中更为普遍。为了确定Aox基因在V. unguiculata中的表达，对种子发育（花、豆荚和干种子）和萌发（浸泡种子）中涉及的转录物进行稳态分析，并在萌发过程中观察到VuAox 1和VuAox 2b的系统共表达。对不同胁迫条件（冷、PEG、水杨酸盐和H2O）下幼苗叶片中Aox转录物的分析揭示了胁迫诱导的两个VuAox基因的共表达。VuAox 2a和26的转录本在所有对照幼苗中均被检测到，而VuAox 1的mRNA则未被检测到。对长爪野豌豆和大豆Aox基因的初级转录物长度的估计显示，VuAox 1和26的内含子长度减少，表明这两个基因在转录序列长度上已经收敛。事实上，VuAox1和26启动子的生物信息学分析揭示了一个保守的区域，该区域与顺式元件相关，该元件对氧化应激有反应。总之，这些数据提供了证据，AOX1和AOX2b的共表达响应于应力，也在种子萌发的早期阶段。VuAox2b表达的双重性质（组成型和诱导型）表明长爪弧菌的组成型Aox2b基因具有诱导型调控元件。(C)2009年Elsevier GmbH。All rights reserved.
Cowpea (Vigna unguiculata) alternative oxidase is encoded by a small multigene family (Aox1, 2a and 26) that is orthologous to the soybean Aox family. Like most of the identified Aox genes in plants. VuAox1 and VuAox2 consist of 4 exons interrupted by 3 introns. Alignment of the orthologous Aox genes revealed high identity of exons and intron variability, which is more prevalent in Aox1. In order to determine Aox gene expression in V. unguiculata, a steady-state analysis of transcripts involved in seed development (flowers, pods and dry seeds) and germination (soaked seeds) was performed and systemic co-expression of VuAox1 and VuAox2b was observed during germination. The analysis of Aox transcripts in leaves from seedlings under different stress conditions (cold, PEG, salicylate and H(2)O(2)) revealed stress-induced co-expression of both VuAox genes. Transcripts of VuAox2a and 26 were detected in all control seedlings, which was not the case for VuAox1 mRNA. Estimation of the primary transcript lengths of V. unguiculata and soybean Aox genes showed an intron length reduction for VuAox1 and 26, suggesting that the two genes have converged in transcribed sequence length. Indeed, a bioinformatics analysis of VuAox1 and 26 promoters revealed a conserved region related to a cis-element that is responsive to oxidative stress. Taken together, the data provide evidence for co-expression of Aox1 and Aox2b in response to stress and also during the early phase of seed germination. The dual nature of VuAox2b expression (constitutive and induced) suggests that the constitutive Aox2b gene of V. unguiculata has acquired inducible regulatory elements. (C) 2009 Elsevier GmbH. All rights reserved.