拟南芥失绿突变体生理特性及其基因定位  

Physiological Characteristics and Gene Mapping of a Chlorotic Mutant in Arabidopsis thaliana

作　　者：瞿方茜 王秀云 赵芳梦 夏宜平[1] 周泓[1] Qu Fangqian;Wang Xiuyun;Zhao Fangmeng;Xia Yiping;Zhou Hong(Genomics and Genetic Engineering Laboratory of Ornamental Plants,College of Agriculture and Biotechnology,Zhejiang University,Hangzhou,310058)

机构地区：[1]浙江大学农业与生物技术学院,观赏植物基因组与基因工程实验室,杭州310058

出　　处：《分子植物育种》2023年第8期2677-2684,共8页Molecular Plant Breeding

基　　金：浙江省农业新品种重大专项花卉育种专项(2021C02071-2);浙江省基础公益研究计划项目(LGN21C160-014)共同资助。

摘　　要：通过筛选T-DNA插入突变体库得到一种叶色失绿拟南芥突变体yg (yellow green),为了研究该失绿突变体的性状变化及发生原因,对其表型、光合色素含量、叶绿体超微结构进行观察或测量,并通过染色体步移法定位了突变基因和T-DNA插入位点。研究发现,突变体yg整个生长期均呈浅黄绿色或黄色,植株瘦弱,生长迟缓,干鲜比、植株高度、基部抽薹数均低于野生型;其叶绿素a、叶绿素b、类胡萝卜素含量相对野生型分别减少了90.6%、89.6%、79.7%;透射电镜观察表明,该突变体叶绿体发育异常,类囊体排列松散,基粒片层断裂,淀粉粒较少,嗜锇颗粒数量显著增加;基因定位发现yg的CHLI1基因发生突变,T-DNA插入点位于5’UTR第24 bp后,导致该基因表达量显著降低。本研究明确了该突变体的失绿机制,进一步证实了CHLI1基因在叶绿素合成过程中的重要功能。A chlorotic mutant of Arabidopsis thaliana named yg(yellow green)was obtained by screening the T-DNA insertion mutants.In order to study the character changes and causes of yg mutant,its phenotypes,photosynthetic pigment content and chloroplast ultrastructure were observed or measured,the mutant gene and T-DNA insertion point were then localized by genome walking assay.The results show that yg mutant is light yellow-green or yellow throughout the growth period.It is weak,fragile and slow-growing.The ratio of dry and fresh weight,plant height,and basal branch number are lower than those of the wild type.Compared with the wild type,the contents of chlorophyll a,chlorophyll b and carotenoid decreased by 90.6%,89.6% and 79.7%respectively.Transmission electron microscopy shows that the chloroplasts of yg mutant are abnormal,with loosely arranged thylakoids,broken grana lamellae,less starch grains and more osmiophilic granules.Gene mapping reveals it is the CHLIl gene of yg that mutates,and the T-DNA is inserted afer the 24 bp site of the 5'UTR,resulting in a significant decrease in the expression of this gene.This study determined the chlorina mechanism of the mutant,and further confirmed the important function of CHLIl gene in chlorophyll synthesis.

关 键 词：拟南芥 突变体 失绿 CHLI1 叶绿体 

分 类 号：Q943.2[生物学—植物学]