玉米性别决定基因tasselseed10的精细定位及候选基因分析  

Fine Mapping and Candidate Gene Analysis of Maize(Zea mays)Sex Determination Gene tasselseed10

作　　者：朱思颖 朱婷婷[1] 李婷[1] 邓屏 向晓芹 王久光[1] 王国强[1] 刘朝显[1] ZHU Si-Ying;ZHU Ting-Ting;LI Ting;DENG Ping;XIANG Xiao-Qin;WANG Jiu-Guang;WANG Guo-Qiang;LIU Chao-Xian(Maize Research Institute/Engineering Research Center of South Upland Agriculture,Ministry of Education/Chongqing Key Laboratory of Crop Molecular Improvement,Southwest University,Beibei 400715,China)

机构地区：[1]西南大学玉米研究所/南方山地农业教育部工程研究中心/作物分子改良重庆市重点实验室,北碚400715

出　　处：《农业生物技术学报》2025年第2期237-247,共11页Journal of Agricultural Biotechnology

基　　金：重庆市技术创新与应用发展专项重点项目(CSTB2022TIAD-KPX0008,CSTB2022TIAD-KPX0007);重庆市玉米产业技术体系项目(CQMAITS2302)。

摘　　要：玉米(Zea mays)是研究性别决定分子机制的重要模式植物,雄穗和雌穗性别决定研究对改良玉米花序结构、提高产量具有重要意义。本研究利用甲基磺酸乙酯(ethyl methane sulfonate,EMS)处理玉米自交系'B73'花粉鉴定到了1个玉米性别决定相关的雄穗结实突变体tasselseed10(ts10)。在田间,ts10突变体营养生长正常,抽雄后雄穗主穗、侧枝中上部小穗的性别发生反转,产生大量花丝,而顶端小穗可正常散粉。扫描电镜观察发现,当雄穗花序分生组织长约12 mm时,小花呈现心皮化的结构。利用图位克隆的方法,把ts10基因定位于玉米1号染色体SSR标记PL4和PR5之间约600 kb的区间内;该区间有7个注释基因,通过测序发现仅有髓细胞组织增生7(myelocytomatosis 7,ZmMyc7)基因序列产生了突变,其编码序列中的第1594个碱基G转换为碱基A,导致编码蛋白的第532个氨基酸谷氨酸被替换为赖氨酸,进一步分析发现该突变位点位于ZmMyc7保守结构域HLH中。表达分析结果显示,ZmMyc7在玉米的根、茎、叶、雄穗、雌穗和籽粒中均有表达,其中在雌穗中表达量最高,其次是雄穗;除了叶,ZmMyc7在ts10和正常植株中根、茎、雄穗、雌穗、胚和胚乳中的表达无显著差异。亚细胞定位结果表明ZmMyc7在细胞核内发挥功能。本研究为丰富玉米性别决定分子机制提供了进一步的理论支持和基因资源。Maize(Zea mays)is an important model plant to decipher the molecular mechanism of sex determination.The research on sex determination of tassel and ear is of great significance to improve the inflorescence architecture and increase yield.In this study,a maize sex determination mutant tasselseed10(ts10)that could produce kernel on tassel was identified by treating B73 pollen with ethyl methane sulfonate(EMS).In fields,the vegetative growth of the ts10 was normal.When tassels emerged,the spikelets on middle and upper of main spikes and branches showed sex reversal,which could produce a large quantity of silks.While the apical spikelets could shed pollens normally.Phenotype observation under scanning electron microscope indicated when the male inflorescence meristem of ts10 was about 12 mm long,the florets produced feminized structure.Using map-based cloning strategy,the ts10 gene was narrowed down to a region of about 600 kb between the SSR markers PL4 and PR5 on Chr.1,which harbored 7 annotated genes.Sequencing analysis revealed that only the myelocytomatosis 7(ZmMyc7)produced a mutation in which the 1594th base G was substituted by base a resulting in the 532nd amino acid glutamic acid substituted by lysine.Further analysis suggested the mutation was located at the conserved domain HLH of ZmMyc7.Expression analysis showed that ts10 was expressed in root,stem,leaf,immature tassel,immature ear and kernel,among which the expression level in ear was the highest,followed by tassel;in addition,except for leaf,there was no significant difference in expression level of ZmMyc7 between ts10 and normal plants in root,stem,immature tassel,immature ear,embryo and endosperm.The subcellular localization results showed ZmMyc7 functions in nucleus.This study provides further theoretical support and genetic resources for enriching the molecular mechanism of sex determination in maize.

关 键 词：玉米 ts10(tasselseed10) 性别决定 候选基因分析 

分 类 号：S513[农业科学—作物学]