黄瓜白化突变体分析与突变基因al的精细定位  

Characteristic and fine-mapping of albino cotyledons(al)mutant in cucumber(Cucumis sativus L.)

作　　者：牛玉倩 李征[1] NIU Yuqian;LI Zheng(College of Horticulture,Northwest A&F University,Yangling,Shaanxi 712100,China)

机构地区：[1]西北农林科技大学园艺学院,陕西杨凌712100

出　　处：《西北农林科技大学学报（自然科学版）》2021年第5期88-95,122,共9页Journal of Northwest A&F University(Natural Science Edition)

基　　金：国家自然科学基金项目(31672150,31872111)。

摘　　要：【目的】对黄瓜白化叶片突变体进行生理和遗传分析,并对该突变基因al进行精细定位,为阐明影响黄瓜叶绿体发育的重要代谢或调控机制提供参考。【方法】以2个不同背景的黄瓜材料Gy14和9930为亲本,分别与携带白化突变基因的杂合材料649构建F 2群体。对F 2群体中的野生型和白化突变体进行光合色素含量测定及叶绿体结构观察,同时筛选多态性分子标记引物,结合基因组重测序技术,对突变基因al进行精细定位。【结果】对al突变体进行表型观察,发现刚出土时其子叶颜色浅黄,之后逐渐白化,确定该白化突变为致死突变性状。与野生型相比,al突变体光合色素含量均极显著低于野生型,且叶绿素a、叶绿素b含量平均降低了90%以上。通过透射电镜对叶肉细胞内叶绿体结构进行观察发现,与野生型相比,al突变体子叶叶肉细胞中几乎无法观察到叶绿体的存在。对al突变体进行遗传分析发现,该白化性状是由一对隐性核基因控制的质量性状。通过BSA、分子标记定位、基因组重测序和染色体步移等方法,最终将al基因定位于黄瓜第7号染色体上约66 kb区间内。【结论】黄瓜白化突变的形成与叶绿体的形成密切相关,由单基因突变产生,定位于黄瓜第7号染色体上。【Objective】Physiological and genetic analysis as well as fine-mapping of a cucumber albino cotyledons(al)mutant were conducted to provide reference for elucidating important metabolic or regulatory mechanisms affecting chloroplast development.【Method】Two cucumber materials Gy14 and 9930 with different backgrounds were used as parents to develop two F 2 populations with heterozygous material 649 carrying al mutant gene,respectively.Photosynthetic pigment content and chloroplast structure of wild-type and al mutants in the F 2 population were analyzed,and polymorphic molecular markers were screened for mapping.【Result】Phenotypic observation of the al mutant showed that cotyledons were pale yellow and then gradually changed to albino before slowly withering and dying.The albino mutation was identified as a fatal mutation.Content of photosynthetic pigment of mutant was significantly lower than that of wild type,and contents of chlorophyll a and chlorophyll b decreased by more than 90%on average.The chloroplast structure in mesophyll cells was observed by transmission electron microscopy.Compared with wild type,chloroplast was hardly observed in cotyledon cells.Genetic analysis of the al mutant revealed that albino trait was a quality trait controlled by a pair of recessive nuclear genes.After BSA,genome re-sequence,and chromosome walking,the al gene was finally located in a 66 kb interval in cucumber chromosome 7.【Conclusion】The formation of this cucumber albino mutation was closely related to formation of chloroplast,resulting in a single gene mutation located in chromosome 7.

关 键 词：黄瓜育种 白化突变体 光合色素 叶绿体 精细定位 

分 类 号：S642.203.2[农业科学—蔬菜学]