The maize d2003, a novel allele of VP8, is required for maize internode elongation
The maize d2003, a novel allele of VP8, is required for maize internode elongation
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DOI：
10.1007/s11103-013-0129-x
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发表时间：
2014-02-01
影响因子：
5.1
通讯作者：
Wang, Guoying
中科院分区：
文献类型：
--
作者：
Lv, Hongkun;Zheng, Jun;Wang, Guoying
d2003是玉米自交系K36的一个自然矮秆突变体，株高不足K36的1/3，节间严重缩短。本研究采用定位克隆法克隆了d2003基因。结果表明，d2003突变株在Viviparous 8（VP 8）编码区有一个单碱基插入，导致提前终止密码子。进一步的等位基因检测证实d2003突变是VP 8的一个新等位基因。VP 8主要在茎尖、幼叶和发育中的维管组织中表达，12叶期在节中的表达量显著高于节间。亚细胞定位结果表明，VP 8蛋白定位于内质网，其N端26个氨基酸（aa）是其在内质网中定位所必需的。进一步的转基因实验表明，缺失26个氨基酸会导致VP 8在拟南芥amp 1表型拯救中的功能丧失。这些结果表明，N端26个氨基酸是VP 8蛋白定位的关键，正确的蛋白定位是VP 8在ER中发挥功能所必需的。
The d2003 is a natural dwarf mutant from maize inbred line K36 and has less than one-third of K36 plant height with severely shortened internodes. In this study, we reported the cloning of d2003 gene using positional cloning. The results showed that there was a single-base insertion in the coding region of Viviparous8 (VP8) in d2003 mutant, which resulted in a premature stop codon. Further genetic allelism tests confirmed that d2003 mutation is a novel allele of VP8. VP8 is mainly expressed in the stem apex, young leaves, and developing vascular tissues, and its expression levels in nodes are significantly higher than that in internodes at 12-leaf stage. Subcellular localization demonstrated that the VP8 protein is localized to the endoplasmic reticulum and the N-terminal 26 amino acids (aa) of VP8 protein are essential to its localization in ER. Further transgenic experiments showed that lack of the 26 aa leads to loss of VP8 function in Arabidopsis amp1 phenotype rescue. These results strongly suggested that the N-terminal 26 aa is critical for VP8 protein localization, and the correct protein localization of VP8 in ER is necessary for its function.