莲种胚发育过程中胚胎晚期丰度蛋白基因表达量与种子含水量相关性分析

通过莲胚形态观察、生理指标测定、蛋白质谱鉴定与基因表达量分析，筛选出莲胚脱水成熟过程中显著富集的LEA蛋白(late embriogenesis abundant protein)，并分析其基因表达量与含水量的相关性。结果表明，莲胚发育成熟共需约30 d，形态发育15~18 d，随后进入脱水成熟阶段。在种胚脱水阶段种胚含水量由80%下降到6.7%，细胞内蛋白含量上升2.75倍。对不同脱水阶段莲胚进行蛋白单向电泳，筛选出7条显著富集的蛋白条带，其中包含7种LEA家族蛋白:EMB564-like、Dehydrin Rab18、Lea14-A与4种D-34类蛋白。Dehydrin Rab18、D-34、D-34-like-1表达量随莲胚脱水而递增，与种子含水量呈负相关；EMB564-like、Lea14-A、D-34-like-2、D-34-like-3基因表达水平呈单峰曲线，在莲胚发育20 d时达到峰值。其中Dehydrin Rab18、EMB564-like与D-34-like-2在莲胚脱水阶段上调表达幅度最大，表达量分别是莲胚脱水前的38.7、11.5、19.0倍，可能与莲胚的逆境保护与耐储存机制相关。

Correlation Analysis of Gene Expression of LEA Protein and Seed Moisture Content During Embryo Maturation in Nelumbo nucifera

LEA (late embryogenesis abundant) proteins accumulate in embryo tissues with high concentrations during the last stage of seed development or accumulate in vegetative tissues exposed to abiotic stresses.In this study,enriched LEA proteins during the dehydration and maturation of lotus embryo were identified based on morphological observation,physiological index measurements,protein identification and gene expression analysis of lotus embryo.Totally,about 30 days were needed for the maturation of lotus embryo.Morphological development took 15-18 d,after which embryo entered late maturation stage.During embryo dehydration,the water content of embryo decreased from 80% to 6.7%,and the protein content increased by 2.75 times.Seven LEA proteins were identified from total protein of lotus embryo:EMB564-like,Dehydrin Rab18,Lea14-A and 4 D-34-like proteins.qRT-PCR revealed two LEA gene expression patterns in lotus embryo.Gene expressions of Dehydrin Rab18,D-34 and D-34-like-1 increased with the dehydration of lotus embryo while expression levels of EMB564-like,LEA14-A,D-34-like-2 and D-34-like-3 showed unimodal curves during the dehydration.Among 7 LEA genes,Dehydrin Rab18,EMB564-like and D-34-like-2 had the highest elevated levels,which were 38.7,11.5 and 19.0 times of those before dehydration,respectively,which may be related to stress resistance and longevity of lotus embryo.