Dwarf and Increased Branching 1 controls plant height and axillary bud outgrowth in Medicago truncatula
Dwarf and Increased Branching 1 controls plant height and axillary bud outgrowth in Medicago truncatula
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矮化和增加分枝 1 控制蒺藜苜蓿的株高和腋芽生长
DOI：
10.1093/jxb/eraa364
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发表时间：
2020
影响因子：
6.9
通讯作者：
Chen J.
中科院分区：
文献类型：
--
作者：
Zhang X;He L;Zhao B;Zhou S;Li Y;He H;Bai Q;Zhao W;Guo S;Liu Y;Chen J.
优化植物构型是育种者提高作物产量的有效途径，赤霉素（gibberellins，GAs）等植物激素在植物生长调控中起着重要作用，蒺藜苜蓿（Medicago truncatulais）是豆科模式植物，但其构型的分子机制尚不清楚。在这项研究中，我们研究了烟草反转录转座子Tnt 1标记的突变体收集M。truncatula和鉴定矮化和增加分支1（dib 1），表现出极端矮化和增加侧枝数量。通过对标记株系不同等位基因中Tnt 1插入片段的侧翼序列分析，克隆了DIB 1。通过对侧翼序列标签的连锁分析和反向筛选，确定Medtr 2g 102570为DIB 1功能缺失突变体中DIB 1位点的对应基因。系统发育分析表明DIB 1与PsGA 3 ox 1/Lein Pisum sativum具有同源性。GUS染色报告基因表达分析表明，DIB 1在根尖、荚果和未成熟种子中均有表达。在dib 1突变体中，内源GA 4浓度显著降低，而一些代表性的GA生物合成酶表达上调。此外，外源GA 3的施用挽救了dib 1突变体的表型。研究结果表明，DIB 1基因通过影响生物活性气体的合成来调控植物的株高和腋芽生长，因此DIB 1基因可作为育种者优化植物结构的候选基因。
Optimizing plant architecture is an efficient approach for breeders to increase crop yields, and phytohormones such as gibberellins (GAs) play an important role in controlling growth.Medicago truncatulais a model legume species, but the molecular mechanisms underlying its architecture are largely unknown. In this study, we examined a tobacco retrotransposonTnt1-tagged mutant collection ofM. truncatulaand identifieddwarf and increased branching 1(dib1), which exhibited extreme dwarfism and increased numbers of lateral branches. By analysis of the flanking sequences ofTnt1insertions in different alleles of the tagged lines, we were able to cloneDIB1.Linkage analysis and reverse screening of the flanking-sequence tags identifiedMedtr2g102570as the gene corresponding to theDIB1locus in thedib1loss-of-function mutants. Phylogenetic analysis indicated thatDIB1was the ortholog ofPsGA3ox1/LeinPisum sativum. Expression analysis using a GUS-staining reporter line showed thatDIB1was expressed in the root apex, pods, and immature seeds. Endogenous GA4concentrations were markedly decreased whilst some of representative GA biosynthetic enzymes were up-regulated in thedib1mutant. In addition, exogenous application of GA3rescued thedib1mutant phenotypes. Overall, our results suggest thatDIB1controls plant height and axillary bud outgrowth via an influence on the biosynthesis of bioactive GAs.DIB1could therefore be a good candidate gene for breeders to optimize plant architecture for crop improvement.