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Sci Rep:中科院青岛能源所周功克研究组发表杨树细胞壁分子调控论文

摘要 : 木材是地球上重要的可再生资源,是造纸、板材、生物能源等工业的主要原材料,具有十分重要的应用价值。解析木材形成的分子调控机制和调控林木营养生长时间是增加林木产量的有效手段。

 木材是地球上重要的可再生资源,是造纸、板材、生物能源等工业的主要原材料,具有十分重要的应用价值。解析木材形成的分子调控机制和调控林木营养生长时间是增加林木产量的有效手段。最近,中国科学院青岛生物能源与过程研究所植物代谢工程团队研究人员在模式木本植物杨树中功能鉴定了多个MYB转录因子,为遗传改良林木生物量奠定了基础,相关成果在线发表于J. Exp. Bot. (Chai et al., 2014)和Sci. Rep.(Tang et al., 2015)。研究获得了973和国家自然科学基金等项目支持,由青岛能源所研究员周功克和副研究员柴国华主持完成。

该团队研究表明,杨树R2R3-MYB基因家族包含194个成员,形成81个基因对,产生5种不同的进化命运。从中选取8个在茎秆中特异表达的基因深入研究其功能。遗传和生化证据表明,PdMYB10/128基因能够正调控次生木质部的形成,PdMYB90/167和PdMYB92/125基因可能通过赤霉素调控次生木质部形成和开花时间,而PdMYB156/221基因通过直接和间接两条途径调控杨树次生木质部的形成,并提出可能的分子调控网络机制。这些研究成果丰富了人们对细胞壁分子调控机制的认识,为林木基因工程育种提供了重要的理论基础。

图 1 拟南芥和杨树次生细胞壁形成的分子调控网络(部分)。

木材的形成受一个复杂网络的调控,PdMYB221 转录因子处在这个级联调控网络的下游,能够直接抑制纤维素、半纤维素和木质素合成基因的表达。

原文链接:

Poplar PdMYB221 is involved in the direct and indirect regulation of secondary wall biosynthesis during wood formation

原文摘要:

Wood is formed by the successive addition of secondary xylem, which consists of cells with a conspicuously thickened secondary wall composed mainly of cellulose, xylan and lignin. Currently, few transcription factors involved in the direct regulation of secondary wall biosynthesis have been characterized in tree species. Here, we show that PdMYB221, a poplar ortholog of the Arabidopsis R2R3-MYB transcription factor AtMYB4, directly regulates secondary wall biosynthesis during wood formation. PdMYB221 is predominantly expressed in cells of developing wood, and the protein it encodes localizes to the nucleus and acts as a transcriptional repressor. Ectopic expression ofPdMYB221 resulted in reduced cell wall thicknesses of fibers and vessels in Arabidopsis inflorescence stems. The amounts of cellulose, xylose, and lignin were decreased and the expression of key genes synthesizing the three components was suppressed in PdMYB221overexpression plants. Transcriptional activation assays showed that PdMYB221 repressed the promoters of poplar PdCESA7/8, PdGT47C, PdCOMT2 and PdCCR1. Electrophoretic mobility shift assays revealed that PdMYB221 bound directly to the PdCESA8, PdGT47C, and PdCOMT2promoters. Together, our results suggest that PdMYB221 may be involved in the negative regulation of secondary wall formation through the direct and indirect suppression of the gene expression of secondary wall biosynthesis.

来源: Scientific Reports 浏览次数:0

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