摘要
【目的】穗发育对于农作物产量至关重要,而穗顶端败育是谷子产量下降的重要原因之一。通过挖掘谷子穗顶端败育的相关基因,探求谷子穗顶端发育的生物学通路,以期为谷子穗发育遗传机理研究提供理论基础。【方法】利用化学诱变剂甲基硫酸乙酯(ethyl methyl sulfonate,EMS)对野生型豫谷一号(Yugu1)进行诱变,在其后代中发现了一个可以稳定遗传的穗顶端败育的突变体,命名为sipaa1,同时对该突变体的农艺性状进行鉴定。以突变体sipaa1母本,SSR41父本构建的F2定位群体为材料进行遗传分析及图位克隆,确定基因所属染色体以及在该染色体上的位置。对突变体sipaa1和野生型Yugu1的BC1F2进行高通量测序,挖掘定位区间内的候选基因,根据候选基因在谷子不同组织部位表达量的差异,找出在穗部高表达的候选基因。对孕穗期的Yugu1和sipaa1进行转录组测序,寻找差异表达基因并分析差异表达基因富集的生物学通路。【结果】与Yugu1相比,突变体sipaa1的平均株高略有增高,增幅不显著,叶长、叶宽分别降低了10.66%和5.08%。突变体的表型变异主要集中在穗部,最突出的表现是穗顶端小花发育异常,谷穗长和谷穗粗分别降低了11.36%和16.12%,单株穗重、谷码数、单穗粒重及千粒重分别降低了30.02%、32.58%、30.55%和18.18%。通过对sipaa1×SSR41的F2代群体中正常株与突变株的遗传分析表明该突变为隐性单基因控制。经图位克隆将突变基因定位于第1染色体Indel标记1-9.23与1-9.333之间约100 kb的范围内。结合高通量测序数据库,在该定位区间筛选到6个在穗部高表达的候选基因。转录组测序发现,在突变体与野生型之间存在2 768个上调表达基因,507个下调表达基因,且定位区间内有2个差异表达基因主要与激素信号转导、外界胁迫响应、植物-病原互作等生物学通路有关。【结论】谷子穗顶端败育突变体sipaa1由隐性单基因控制,突变基因位于第1染色体Indel标记1-9.23与1-9.333之间,转录组测序与基因功能分析发现了2个在穗部高表达且与植物花器官发育及胁迫响应密切相关的候选基因,候选基因可能通过对激素、胁迫响应,以及细胞程序性死亡等相关通路调控谷子穗顶端败育。
【Objective】Panicle development determines crop yield, and panicle apical abortion is one of the major limitation that affects the grain yield of foxtail millet. Our study explored the genes and biological pathways related to panicle apical abortion in foxtail millet, which provided a theoretical basis for the genetic mechanism of foxtail millet panicle development.【Method】A foxtail millet panicle apical abortion mutant sipaa1, induced from Yugu1 by EMS treatment, was genetically identified. Agronomic traits of the mutant were investigated. The F2 segregating population of sipaa1× SSR41 was used for gene mapping. Based on differential expressed levels of candidate genes in five different tissues of foxtail millet, some genes highly expressed in the panicle was identified. Transcriptome sequencing of Yugu1 and sipaa1 young panicle at booting stage was conducted to find differential expressed genes and to analyze the biological pathways.【Result】The mutant exhibited thinner panicle, shorter leaf, less spikelets per panicle, lower spikelet numbers, as well as lower 1000-grain weight, compared with wildtype Yugu1. The agronomic traits of mutants showed that mutant leaf length, leaf width, panicle length, panicle diameter, panicle weight per plant, spikelet number per panicle, grain weight per spikelet and 1000-grain weight were decreased 10.66%, 5.08%, 11.36%, 16.12%, 30.02%, 32.58%, 30.55%, 18.18%, respectively. Genetic analysis showed that segregating ratio of wild type to mutant plants were 3:1 in sipaa1×SSR41 F2 generation, suggesting that the panicle apical abortion trait of sipaa1 was controlled by a single recessive nuclear gene. By map-based cloning, the candidate gene was mapped into a region between Indel markers In1-9.23 and In1-9.333 in chromosome 1, which contains a 100 kb interval. Combined with transcriptome sequencing, some candidate genes were found. Six candidate genes highly expressed in the panicle were further identified. Moreover, transcriptome sequencing showed that there were 2 768 up-regulated genes and 507 down-regulated genes between mutant and wild type. The differential expressed genes were mainly enriched in hormone signal transduction, external stress responses, plant-pathogen interaction.【Conclusion】Casual gene was limited into a 100 kb region between Indel markers 1-9.23 and 1-9.333 on chromosome 1 of foxtail millet. Combined transcriptome sequencing and gene function analysis, we identified two candidate genes that are highly expressed in panicle, and reported to participate in plant floral development and stress responses. Panicle apical abortion may be regulated by hormone, stress responses, and programmed cell death pathway.
作者
薛红丽
杨军军
汤沙
智慧
王蕊
贾冠清
乔治军
刁现民
XUE HongLi;YANG JunJun;TANG Sha;ZHI Hui;WANG Rui;JIA GuanQing;QIAO ZhiJun;DIAO XianMin(College of Biological Engineering, Shanxi University, Taiyuan 030006;Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beij'ing 100081;Institute of Crop Germplasm Resources, Shanxi Academy of Agricultural Sciences, Taiyuan 030031)
出处
《中国农业科学》
CAS
CSCD
北大核心
2018年第9期1627-1640,共14页
Scientia Agricultura Sinica
基金
国家自然科学基金(31501324)
中国农业科学院科技创新工程(Y2016XT05)
中国农业科学院创新工程杂粮团队
中国农业科学院农科英才特资计划
国家现代农业产业技术体系(CARS07-13.5-A02)
关键词
谷子
穗顶端败育
表型分析
基因定位
转录组测序
Setaria italica
panicle apical abortion
phenotypic analysis
gene mapping
RNAseq