Chen Liang, Zheng Yuhong, Dong Zhimin, Meng Fanfan, Sun Xingmiao, Fan Xuhong, Zhang Yunfeng, Wang Mingliang, Wang Shuming
Soybean Research Institute, Jilin Academy of Agricultural Sciences/National Engineering Research Center for Soybean, Changchun, 130033, People's Republic of China.
Key Laboratory of Soybean Biology in Chinese Ministry of Education, Northeast Agricultural University, Harbin, 150030, People's Republic of China.
Mol Genet Genomics. 2018 Apr;293(2):401-415. doi: 10.1007/s00438-017-1393-2. Epub 2017 Nov 14.
Soybean is the world's most important leguminous crop producing high-quality protein and oil. Elevating oil accumulation in soybean seed is always many researchers' goal. WRINKLED1 (WRI1) encodes a transcription factor of the APETALA2/ethylene responsive element-binding protein (AP2/EREBP) family that plays important roles during plant seed oil accumulation. In this study, we isolated and characterized three distinct orthologues of WRI1 in soybean (Glycine max) that display different organ-specific expression patterns, among which GmWRI1a was highly expressed in maturing soybean seed. Electrophoretic mobility shift assays and yeast one-hybrid experiments demonstrated that the GmWRI1a protein was capable of binding to AW-box, a conserved sequence in the proximal upstream regions of many genes involved in various steps of oil biosynthesis. Transgenic soybean seeds overexpressing GmWRI1a under the control of the seed-specific napin promoter showed the increased total oil and fatty acid content and the changed fatty acid composition. Furthermore, basing on the activated expressions in transgenic soybean seeds and existence of AW-box element in the promoter regions, direct downstream genes of GmWRI1a were identified, and their products were responsible for fatty acid production, elongation, desaturation and export from plastid. We conclude that GmWRI1a transcription factor can positively regulate oil accumulation in soybean seed by a complex gene expression network related to fatty acid biosynthesis.
大豆是世界上最重要的豆科作物，可生产高质量的蛋白质和油脂。提高大豆种子中的油脂积累一直是众多研究人员的目标。皱缩1（WRI1）编码一种APETALA2/乙烯响应元件结合蛋白（AP2/EREBP）家族的转录因子，在植物种子油脂积累过程中发挥重要作用。在本研究中，我们分离并鉴定了大豆（Glycine max）中三个不同的WRI1直系同源基因，它们表现出不同的器官特异性表达模式，其中GmWRI1a在成熟大豆种子中高表达。电泳迁移率变动分析和酵母单杂交实验表明，GmWRI1a蛋白能够与AW-box结合，AW-box是许多参与油脂生物合成各个步骤的基因近端上游区域中的保守序列。在种子特异性napin启动子控制下过表达GmWRI1a的转基因大豆种子显示出总油脂和脂肪酸含量增加以及脂肪酸组成改变。此外，基于转基因大豆种子中的激活表达以及启动子区域中AW-box元件的存在，鉴定了GmWRI1a的直接下游基因，其产物负责脂肪酸的产生、延长、去饱和以及从质体输出。我们得出结论，GmWRI1a转录因子可通过与脂肪酸生物合成相关的复杂基因表达网络正向调控大豆种子中的油脂积累。
