大豆转录因子GmZF调控油脂积累的机制研究

Soybean [Glycine max (L.) Merr.] is the world’s top legume crop with a significant contribution to edible plant proteins and oil. Although the pathways for lipid metabolism in higher plants have been uncovered, our understanding of their regulatory mechanisms is relatively limited. Studies in Arabidopsis have identified some key trascription factors as master regulators to regulate lipid accumulation, either positiviely or negatively. By analyzing transcritome data from different soybean tissues and seeds of various developmental stages, we cloned the gene GmZFa which encoded a CCCH type zinc finger protein. Overexpression of GmZFa increased the fatty acid content of seeds in transgenic Arabidopsis plants. Expression of GmZFa-GFP fusion protein showed that GmZFa was located at nucleus and cytoplasm subcellularly. GmZFa possessed transcriptional activation activity in Arabidopsis protoplast. Difference of the expression pattern and coding genomic sequence of GmZFa between cultivar HN44 and wild species ZYD7 was detected. Eleven transgenic soybean plants overexpressing GmZFa were also generated. The present project will further identify and verify GmZFa-regualted genes. The phenotypes of 11 GmZFa soybean transgenic lines and the relationship of gene expression, phenotype and lipid content among these lines will be characterized. Seed transcriptomic studies from 2 transgenic soybean lines and Jack will be conducted to shed light on GmZFa-involved gene network. Studies on domestication of GmZFa will be carried out based on the expression patterns and coding genomic sequences of GmZFa from 99 different soybean germplasm collections. Contribution of various gene expression patterns and haplotypes of GmZFa to soybean seed lipid accumulation will also be assessed. Completion of this project would be beneficial to novel gene allele discovery from soybean germplasm resources in China.

栽培大豆是人类重要的蛋白质和脂肪营养来源。植物油脂代谢调控机理尚不很清楚。一些被称为Master regulator的转录因子参与了种子油脂积累的转录调控。分析大豆发育籽粒转录组，我们鉴定到一个编码CCCH类锌指蛋白的基因GmZFa；过量表达GmZFa提高了转基因拟南芥籽粒的脂肪酸含量；GmZFa定位于细胞核与细胞质且具有转录激活活性；GmZFa在栽培大豆黑农44和野生大豆ZYD7的表达和序列存在差异；我们获得了11株GmZFa转基因大豆阳性植株。本申请拟鉴定GmZFa直接调控的下游基因并进行验证；分析转基因大豆的表型以及油脂含量与GmZFa表达量的关系；分析GmZFa转基因大豆种子转录组，勾勒GmZFa参与的基因调控网络；根据已有99份种质资源的油脂含量数据计算GmZFa基因表达量和基因序列不同单倍体型与种子油脂含量的相关性，为发掘鉴定新的有益等位基因提供依据。

栽培大豆是人类重要的蛋白质和脂肪营养来源。目前大豆油脂调控机理尚不明确。在项目的资助下，我们对GmZF351调控油脂积累的机制进行了解析。GmZF351编码一个串联CCCH锌指蛋白。GmZF351通过调控大豆中的油脂合成、贮存和调控基因BCCP2、KASIII、TAG1、OLEO2和WRI1的表达，促进油脂在大豆种子中的积累。ZF351在栽培和野生大豆资源中的表达量与油脂含量成正相关。ZF351单倍体型分析发现，GmZF351单倍体型来源于野生大豆III型，与高启动子活性和油脂含量相关联，表明GmZF351在大豆驯化过程中受到人工选择。我们进一步分析了GmZF351结合的DNA元件。同时鉴定了GmZF351互作蛋白GmZF392参与油脂积累调控的功能。我们的研究揭示了大豆中新的油脂积累调控机制，为驯化过程中油脂含量的增加提供了理论支持。GmZF351可以应用于现有大豆品种油脂性状的改良，对提高大豆品质具有重要意义。