星油藤FAD3的N端序列对α-亚麻油酸累积的影响  

Effect of N-terminal Sequence of FAD3 onα-Linolenic Acid Accumulation in Sacha Inchi(Plukenetia volubilis)

作　　者：董亭男 代欢 孙蕊 阳天泉 刘爱忠 Dong Tingnan;Dai Huan;Sun Rui;Yang Tianquan;Liu Aizhong(Key Laboratory for Forest Resource Conservation and Utilization in the Southwest Mountains of China(Ministry of Education),Southwest Forestry University,Kunming,650224;Department of Plant Science,Tibet Agriculture and Animal Husbandy College,Linzhi,860000;Germplasm Bank of Wild Species,Kunming Institute of Botany,Chinese Academy of Sciences,Kunming,650201)

机构地区：[1]西南林业大学,西南山地森林资源保育与利用教育部重点实验室,昆明650224 [2]西藏农牧学院植物科学学院,林芝860000 [3]中国科学院昆明植物研究所,中国西南野生生物种质资源库,昆明650201

出　　处：《分子植物育种》2022年第15期4900-4908,共9页Molecular Plant Breeding

基　　金：中国科学院“西部之光”人才培养计划;国家自然科学基金项目(31571709,31700285);云南省应用基础研究计划面上项目(2018FB037)共同资助。

摘　　要：植物脂肪酸脱饱和酶3(FAD3)是催化亚麻油酸(ALA)合成的关键功能酶。本研究通过对7种油料植物(其种子ALA含量显著不同)FAD3氨基酸序列进行比对发现,不同物种FAD3氨基酸N端序列变化较大,所带净电荷数也有较大的差异。利用小桐子(其种子不累积ALA)FAD3(JcFAD3)和星油藤FAD3(PvFAD3)核酸序列N端的置换,本研究获得了2个新的序列JcFAD3/Pv FAD3和Pv FAD3/JcFAD3。进一步在酵母中表达,发现JcFAD3在酵母系统中具有更高的催化活性,而且在30℃条件下N端序列置换不影响JcFAD3和Pv FAD3酶的脱饱和活性。在20℃条件下培养转化酵母菌株,发现含有星油藤Pv FAD3的N端序列的转化菌株能累积更高的ALA。结果显示在较低的温度下,Pv FAD3的N端序列可能因为富含酸性氨基酸(带负电荷),延缓了蛋白的泛素化降解过程,从而促进了ALA的合成。本研究对理解低温促进星油藤种子ALA累积的生理机制提供了新的依据。Fatty acid desaturase 3(FAD3)is the key enzyme catalyzing α-linolenic(ALA)biosynthesis in plant.In this study,the amino acid sequences of FAD3 proteins were aligned among seven plant species which accumulates different amounts of ALA in their seeds.It showed that these seven FAD3 proteins exhibited high sequence divergence in the N-terminus,and the net charge of amino acid in this region was variable.To elucidate the function of N-terminal sequence of FAD3,we exchanged the N-terminal sequence of FAD3 from Sacha Inchi and FAD3 from Jatropha curcas to generate two chimeric DNA sequences JcFAD3/Pv FAD3 and Pv FAD3/JcFAD3.The transformed yeast strains were cultured at 20℃,and it was found that the transformed strains containing the N-terminal sequence of Pv FAD3 could accumulate higher ALA.The results showed that at low temperature,the N-terminal sequence of Pv FAD3 may be rich in acidic amino acids(negatively charged),which delayed the ubiquitination process of protein degradation,thus promoting the synthesis of ALA.These findings provide new sight to understand the mechanism basis of low growth temperature promoting ALA accumulation in Sacha Inchi seed.

关 键 词：星油藤 Α-亚麻酸 脂肪酸脱饱和酶3(FAD3) 温度敏感 

分 类 号：S565.9[农业科学—作物学]