Overexpression of Arabidopsis YUCCA6 in Potato Results in High-Auxin Developmental Phenotypes and Enhanced Resistance to Water Deficit
Overexpression of Arabidopsis YUCCA6 in Potato Results in High-Auxin Developmental Phenotypes and Enhanced Resistance to Water Deficit
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DOI：
10.1093/mp/sss100
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发表时间：
2013-03-01
期刊：
影响因子：
27.5
通讯作者：
Yun, Dae-Jin
中科院分区：
文献类型：
--
作者：
Kim, Jeong Im;Baek, Dongwon;Yun, Dae-Jin
吲哚-3-乙酸（Indole-3-acetic acid，IAA）是一种重要的植物生长素，其产生途径既有依赖于内源激素的途径，也有不依赖于内源激素的途径。拟南芥中的一个主要途径是通过两个反应从色氨酸产生IAA。第一步通过色氨酸氨基转移酶将色氨酸转化为吲哚-3-戊酸（IPA），然后是由YUCCA蛋白催化的将IPA转化为IAA的限速步骤。我们鉴定了8个StYUC（Solanum tuberosum YUCCA）基因，其推导的氨基酸序列与拟南芥YUCCA蛋白有50%~ 70%的同源性。所有包括典型的，保守的YUCCA序列：FATGY基序，FMO签名序列，FAD结合和NADP结合序列。此外，发现5个基因与拟南芥色氨酸氨基转移酶具有相似的50%的氨基酸序列同一性。转基因马铃薯（Solanum tuberosum cv. Jowon）组成型过表达拟南芥AtYUC 6表现出高生长素表型，如狭窄的向下卷曲的叶子，增加的高度，直立的身材，和长寿。过表达AtYUC 6的转基因马铃薯植株表现出基于减少水分损失的增强的耐旱性。该表型与叶片中活性氧水平降低相关。这些结果表明，马铃薯生长素生物合成的功能性YUCCA途径可能被利用来改变植物对环境的反应。
Indole-3-acetic acid (IAA), a major plant auxin, is produced in both tryptophan-dependent and tryptophan-independent pathways. A major pathway in Arabidopsis thaliana generates IAA in two reactions from tryptophan. Step one converts tryptophan to indole-3-pyruvic acid (IPA) by tryptophan aminotransferases followed by a rate-limiting step converting IPA to IAA catalyzed by YUCCA proteins. We identified eight putative StYUC (Solanum tuberosum YUCCA) genes whose deduced amino acid sequences share 50%70% identity with those of Arabidopsis YUCCA proteins. All include canonical, conserved YUCCA sequences: FATGY motif, FMO signature sequence, and FAD-binding and NADP-binding sequences. In addition, five genes were found with similar to 50% amino acid sequence identity to Arabidopsis tryptophan aminotransferases. Transgenic potato (Solanum tuberosum cv. Jowon) constitutively overexpressing Arabidopsis AtYUC6 displayed high-auxin phenotypes such as narrow downward-curled leaves, increased height, erect stature, and longevity. Transgenic potato plants overexpressing AtYUC6 showed enhanced drought tolerance based on reduced water loss. The phenotype was correlated with reduced levels of reactive oxygen species in leaves. The results suggest a functional YUCCA pathway of auxin biosynthesis in potato that may be exploited to alter plant responses to the environment.