杨静园 阮孟斌 郭鑫 彭明

摘  要：MYB转录因子是植物最大的转录因子家族之一，其部分成员在植物非生物胁迫响应过程中发挥着重要的调控作用。通过转录组数据分析，筛选到了多个木薯干旱胁迫相关的MYB类基因，本研究针对其中的1个MYB转录因子MeMYB2展开研究。MeMYB2蛋白N末端与AtMYB60蛋白的N末端氨基酸序列具有95%以上的相似度，但其C末端氨基酸序列与AtMYB60只有30%左右的相似度。编码该蛋白的基因在木薯成熟叶片中优势表达，并且其表达受干旱胁迫负调控。MeMYB2蛋白主要定位于细胞核中，且在酵母中具有明显的转录自激活活性，其转录激活结构域在蛋白C末端247～267位点之间的20个氨基酸残基内。利用酵母双杂交系统从木薯cDNA文库中筛选到了8个与MeMYB2互作的蛋白，其中的2个蛋白与气孔运动和光合作用有关。MeMYB2-RNAi转基因木薯成熟叶片的失水率显著低于野生型木薯成熟叶片，说明MeMYB2转录因子负调控木薯叶片失水率，推测其可能具有调控气孔运动的功能。

关键词：木薯;干旱胁迫;MeMYB2转录因子

中图分类号：S533      文献标识码：A

Characterization and Function Analysis of Cassava MYB Transcription Factor MeMYB2

YANG Jingyuan1， RUAN Mengbin2*， GUO Xin3， PENG Ming2

1. Heilongjiang Bayi Agricultural University， Daqing， Heilongjiang 163000， China; 2. Institute of Tropical Bioscience and Biotechnology， Chinese Academy of Tropical Agricultural Sciences， Haikou， Hainan 571101， China; 3. Huazhong Agricultural University， Wuhan， Hubei 430070， China

Abstract： MYB transcription factor family is one of the largest transcription factor families in plants， playing key roles in stress response of many plants. Based on transcriptome data analysis， we have identified several drought-responsive MYB members from cassava （Manihot esculenta）. Herein， were perform characterization and function analyses on one of these drought-responsive MYB transcription factors， namely MeMYB2. MeMYB2 had 95% amino acid similarity with AtMYB60 in its N-terminus， whereas only 30% amino acid similarity was found in their C-terminus. MeMYB2 was specifically expressed in cassava leaves and was down-regulated by drought stress. Subcellular localization analysis indicated that MeMYB2 was localized in nucleus. Furthermore， MeMYB2 showed transcriptional activity in yeast， and the transcription activated domain was located within a 20 amino acid fragment between the 247-267AA position. Eight proteins were identified as the MeMYB2 binding protein according to the result of yeast two hybrid analysis. Two of these proteins are related to stomatal movement regulation and photosynthesis. The mature leaves of MeMYB2-RNAi transgenic cassava showed lower water loss rate than that of wild type， suggesting the roles of MeMYB2 in regulation of stomatal movement.

Keywords： cassava; drought stress; MeMYB2 transcription factor

DOI： 10.3969/j.issn.1000-2561.2021.04.004

木薯（Manihot esculenta）是三大薯類作物、六大粮食作物之一，主要生长于热带和亚热带地区，是南亚热带地区广泛种植的、用于加工淀粉和饲料的主要作物。随着我国社会经济的快速发展，对木薯相关产品需求量不断增加，木薯种植规模不断扩大。然而，热带地区的间歇性干旱使木薯种植规模的扩大受到了严重的限制。另外，作为一种典型的热带作物，对木薯响应干旱胁迫相关基因的研究不但可以挖掘木薯中的抗逆相关的功能基因，为木薯分子育种提供优秀的基因资源，而且有助于了解植物响应干旱胁迫的分子机制。……