Identification and characterization of a natural SNP variant in ALTERNATIVE OXIDASE gene associated with cold stress tolerance in watermelon
Identification and characterization of a natural SNP variant in ALTERNATIVE OXIDASE gene associated with cold stress tolerance in watermelon
复制标题
与西瓜耐冷胁迫相关的替代氧化酶基因中天然 SNP 变体的鉴定和表征
DOI：
10.1016/j.plantsci.2020.110735
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发表时间：
2021-02-07
期刊：
影响因子：
5.2
通讯作者：
Zhang, Mingfang
中科院分区：
文献类型：
--
作者：
Ding, Changqing;Chen, Cuiting;Zhang, Mingfang
交替氧化酶(AOX)是由一个小的核基因家族编码的线粒体酶，包含AOX1和AOX2两个亚家族。在对西瓜(Citrullus Lanatus)的研究中，仅在西瓜基因组中发现了一个ClAOX基因，该基因属于AOX2亚家族，但与AtAOX1a具有相似的基因结构。表达分析表明，ClAOX具有AOX2亚家族的组成表达特征，但具有冷诱导特性，这通常被认为是AOX1亚家族的特征。此外，在西瓜亚种间还发现了ClAOX序列中的一个单核苷酸多态(SNP)，导致第96个氨基酸由Lys(N)变为Asn(K)。两个ClAOX等位基因在拟南芥Aox1a基因敲除突变体中的异位表达表明，表达ClAOX K的植株比表达Aox1a突变体和表达ClAOX N的植株具有更强的耐冷性。我们的发现表明，西瓜基因组中只有一个ClAOX，它同时具有AOX1和AOX2亚家族的表达特征。ClAOX中的一个自然存在的SNP区分了转基因拟南芥植株的耐冷性，暗示该基因可能是耐逆性育种的功能标记。
Alternative oxidase (AOX) is a mitochondrial enzyme encoded by a small nuclear gene family, which contains the two subfamilies, AOX1 and AOX2. In the present study on watermelon (Citrullus lanatus), only one ClAOX gene, belonging to AOX2 subfamily but having a similar gene structure to AtAOX1a, was found in the watermelon genome. The expression analysis suggested that ClAOX had the constitutive expression feature of AOX2 subfamily, but was cold inducible, which is normally considered an AOX1 subfamily feature. Moreover, one single nucleotide polymorphism (SNP) in ClAOX sequence, which led to the change from Lys (N) to Asn (K) in the 96th amino acids, was found among watermelon subspecies. Ectopic expression of two ClAOX alleles in the Arabidopsis aox1a knock-out mutant indicated that ClAOX K-expressing plants had stronger cold tolerance than aox1a mutant and ClAOX N-expressing plants. Our findings suggested watermelon genome contained a single ClAOX that possessed the expression features of both AOX1 and AOX2 subfamilies. A naturally existing SNP in ClAOX differentiated the cold tolerance of transgenic Arabidopsis plants, impling a possibility this gene might be a functional marker for stress-tolerance breeding.