基于转录组测序的烟草黄叶突变体叶色黄化相关基因挖掘

Discovery of Related Genes in Tobacco Yellow Leaf Mutant Based on Transcriptome Technology

为解析烟草黄叶突变体叶色黄化机制,本研究以黄叶突变体、‘黄叶K326’和‘K326’为试验材料,从叶绿素含量及转录水平两个方面开展了研究。结果表明,两种黄叶材料整个生育期叶片中叶绿素含量显著低于‘K326’,成苗期差异最大,黄叶突变体、‘黄叶K326’叶片的叶绿素含量分别为‘K326’的58.57%和52.07%;通过转录组分析发现,两种黄叶材料与‘K326’间有935个DEGs,这些DEGs涉及萜类生物合成、卟啉和叶绿素代谢、RNA修饰加工等过程;进一步分析发现叶绿素合成中编码镁螯合酶的CHLD、CHLH基因在两种黄叶材料叶片中表达量显著下调,筛选到14个叶绿体发育及分化有关的DEGs,包括EMB2654、PGR3、GLB1、WAXY等基因,这些DEGs在两种黄叶材料大部分表现为下调。说明该黄叶突变基因可能通过影响CHLD、CHLH、EMB2654、PGR3、RAP等基因表达,使得叶绿体发育不良,叶绿素含量降低,引起叶色黄化。本研究结果为突变基因的克隆及进一步功能分析提供理论依据。

In order to analyze the mechanism of leaf color yellowing in yellow leaf mutants leaf color of tobacco,the present study studied the chlorophyll content and transcription level of yellow leaf mutants,’Yellow leaf K326’and’K326’as experimental materials.The results showed that the chlorophyll content in the leaves of the two yellow-leaf materials during the whole growth period was significantly lower than that of’K326’,and the difference in the seedling stage was the largest.The chlorophyll content of the yellow leaf mutant and’Yellow Leaf K326’was 58.57%and 52.07%of that of’K326’,respectively;Transcriptome analysis showed that there were 935DEGs between the two yellow leaf materials and’K326’,these DEGs were involved in terpenoid biosynthesis,porphyrin and chlorophyll metabolism,RNA modification and processing;further analysis showed that the expression levels of CHLD and CHLH genes encoding magnesium chelase in chlorophyll synthesis were significantly down-regulated in the leaves of the two yellow leaf materials,and 14 DEGs related to chloroplast development and differentiation were screened,including EMB2654,PGR3,GLB1,WAXY and other genes.Most of these DEGs showed downregulated in the two yellow leaf materials.These results suggest that the mutant gene may affect the expression of CHLD,CHLH,EMB2654,PGR3,RAP and other genes,resulting in chloroplast dysplasia,decreased chlorophyll content,and yellowing of leaf color.This study provides theoretical basis for cloning and further functional analysis of mutated genes.