摘要
玉米花序的正常发育是玉米产量的根本保证.鉴定和挖掘调控花序模式建成的基因和代谢通路将有助于揭示花序发育的分子机制,为提高玉米产量提供理论指导.本研究从Mo17 背景的EMS突变体库中筛选到一个玉米花序发育模式改变的材料,命名为altered flower pattern 1(afp1).表型鉴定结果发现,afp1 雌穗产生一系列侧生分枝、且无花丝形成;雄穗上侧生小穗数量显著增多.遗传学分析表明,afp1 性状受一对隐性核基因控制.利用afp1 与B73构建的 F2 分离群体进行连锁分析,该基因被定位在第 7 号染色体分子标记 M150～M176 之间.利用该区间内新开发的 14 对多态性标记进行精细定位,afp1 被限定在分子标记M1722 和M1725 间约 300 kb的范围内,其间包含一个已知调控玉米花序发育基因BD1(Branched silkless1).通过测序发现,afp1 的BD1 发生一处C-T的变异,引起BD1 蛋白的第 67 位精氨酸(R)变为色氨酸(W),该突变位于保守的功能域ERF/AP2 上.对发育早期的野生型与afp1 雌穗进行RNA-seq分析后发现,afp1相比野生型存在274个差异表达基因(differentially expressed genes,DEGs),其中56.20%基因表达下调,43.80%基因表达上调.通过KEGG分析发现,差异表达基因富集到多种代谢通路,其中富集到植物激素信号转导途径中的 83.30%基因表达量都显著下调,说明afp1 可能通过影响激素信号从而改变花序发育模式.
Abstract
The normal development of maize inflorescence is the foundation of yield.Mining genes and metabolic pathways can reveal the molecular mechanism of inflorescence development,which will provide a theoretical guidance for maize yield im-provement.In this study,a mutant with altered flower pattern 1(named afp1)was screened from a Mo17 EMS mutant library.The afp1 mutant showed excrescent branches with no silk in the ear,while it increased the lateral spikelet number in the tassel.Genetic analysis revealed that the afp1 phenotype was controlled by a single recessive gene.The gene was initially restricted between M150 and M176 on chromosome 7 by linkage analysis in the afp1×B73 F2 population.It was further narrowed into a 300 kb re-gion between M1722 and M1725 with 14 newly developed molecular markers.Within the mapping region,a known gene related to inflorescence development,BD1(Branched silkless 1),was located.Due to a C-T mutation in afp1,the 67th conserved arginine(R)in the ERF/AP2 domain of the BD1 protein was altered into tryptophan(W).A total of 274 differentially expressed genes(DEGs)were identified between young ears in afp1 and the wild-type by RNA-seq.Among these genes,56.20%were down-regulated and 43.80%were up-regulated,which were enriched in multiple metabolic pathways by KEGG analysis.Among them,83.3%of DEGs in phytohormone signaling pathways were significantly down-regulated,suggesting that afp1 may modu-late inflorescence development via a hormone-dependent pathway.
基金项目
江苏省种业振兴揭榜挂帅项目(JBGS[2021]002)
江苏省重点研发计划项目(JBGS[2021]002)
维普
万方数据