玉米矮化突变体gad39的遗传分析与分子鉴定  

Genetic analysis and molecular characterization of dwarf mutant gad39 in maize

作　　者：刘磊 詹为民 丁武思 刘通 崔连花 姜良良 张艳培 杨建平[1] LIU Lei;ZHAN Wei-Min;DING Wu-Si;LIU Tong;CUI Lian-Hua;JIANG Liang-Liang;ZHANG Yan-Pei;YANG Jian-Ping(College of Agriculture,Henan Agricultural University,Zhengzhou 450002,Henan,China)

机构地区：[1]河南农业大学农学院,河南郑州450002

出　　处：《作物学报》2022年第4期886-895,共10页Acta Agronomica Sinica

基　　金：国家自然科学基金项目(31871709);河南省技术创新引导专项(182106000050);北京市自然科学基金(重点)项目(6151002)资助。

摘　　要：株高决定了玉米的种植密度和抗倒伏性,进而影响产量和品质,是玉米育种中重要的选择性状之一,因此对控制玉米株高相关基因的遗传和分子机制的研究具有重要意义。本文对源自玉米自交系Mo17的矮化自然突变体gad39进行了表型鉴定、细胞学观察、遗传分析、基因定位和赤霉素(GA3)处理等研究。田间种植条件下,整个生育期gad39的株高都明显矮于野生型Mo17,吐丝期仅100.00 cm,与野生型的192.60 cm相比,下降了48.08%,差异达到极显著水平;进一步分析发现gad39的雄穗长度显著变短,节间数目显著减少。扫描电镜观察发现,茎秆纵向细胞的宽度和长度显著变小。雄穗变短、节间数目减少和纵向细胞变小是导致gad39植株矮化的主要原因。除植株矮化外,gad39分蘖数增加,穗位降低,茎秆变细,叶片变短和雌穗变短。遗传分析表明,gad39的突变表型由1对隐性核基因控制,将控制矮化性状的基因定位在3号染色体长臂td4和td6标记之间。这2个标记之间的物理距离为15.34 kb,其间包含一个控制植株矮化的基因D1/ZmGA3ox2。测序发现,gad39中的D1基因具有10个InDels和21个SNPs,导致外显子中4个氨基酸的变异。gad39的突变位点与已报道的dwarf1、d1-4、d1-6016和d1-3286突变体不同,是D1基因一个新的等位突变体。D1/ZmGA3ox2编码GA3氧化酶(GA3-oxidase,GA3ox),是活性GA生物合成途径中的重要酶之一。对gad39突变体施加GA_(3)处理,其株高恢复至野生型水平。本研究在玉米中发现一个新的矮化等位突变遗传材料,为进一步解析玉米株高的遗传机制奠定了基础。Plant height is one of the important selection characters in maize breeding,which determines planting density and lodging resistance,and further affects yield and quality.Therefore,it is of great significance to study the genetic and molecular mechanism of related genes controlling plant height in maize.We performed phenotypic identification,cytological observation,genetic analysis,gene mapping,and gibberellin(GA3)treatment of dwarf mutant gad39,which is derived from maize inbred line Mo17.At silking stage,the plant height of gad39 was only 100.00 cm,significantly shorter than 192.60 cm of wild type Mo17,resulting in a decrease of 48.08%.Morphological identification showed that tassel length,internode number,and cell size of gad39 mutant were significantly reduced,which might be the main cause of gad39 dwarfism.In addition to plant dwarfness of gad39,the number of tillers increased,ear position decreased,stem became thinner,leaf length became shorter and ear length became shorter.Genetic analysis showed that a single recessive nuclear gene regulated the gad39 mutant phenotype,and gene controlling dwarf trait was mapped between markers td4 and td6 on the long arm of chromosome 3.The physical distance between the two markers was 15.34 kb,which contained a dwarf gene D1/ZmGA3ox2.Sequence analysis also revealed that D1 allele gene in gad39 had 10 InDels and 21 SNPs,resulting in the variations of four amino acids in exons.Mutation sites of gad39 differed from the previously reported sites of mutant dwarf1,d1-4,d1-6016,and d1-3286.In conclusion,gad39 was a novel allelic mutant of D1,which encoded GA3-oxidase(GA3ox),a key enzyme involved in the bioactive GA biosynthesis.The seedling height of gad39 was restored to the level of wild types by GA_(3) treatment.In this study,we detected a new dwarfing allelic mutant,which laid a foundation for further analyzing the genetic mechanism of plant height in maize.

关 键 词：玉米 矮化 遗传分析 基因定位 赤霉素 

分 类 号：S513[农业科学—作物学]