Meiotic chromosome stability of a newly formed allohexaploid wheat is facilitated by selection under abiotic stress as a spandrel
Meiotic chromosome stability of a newly formed allohexaploid wheat is facilitated by selection under abiotic stress as a spandrel
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通过在非生物胁迫下作为拱肩进行选择，促进了新形成的异源六倍体小麦的减数分裂染色体稳定性
DOI：
10.1111/nph.15267
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发表时间：
2018-10-01
期刊：
影响因子：
9.4
通讯作者：
Liu, Bao
中科院分区：
文献类型：
--
作者：
Bian, Yao;Yang, Chunwu;Liu, Bao
多倍体是植物物种形成的重要途径;然而，这需要解决染色体互补突然加倍所面临的减数分裂不稳定性的挑战。我们将人工合成的六倍体小麦（类似于天然普通小麦，但表现出广泛的减数分裂染色体不稳定性）的后代进行热或盐胁迫。我们选择耐胁迫的群体，并在正常条件下产生后代。我们通过荧光原位杂交/基因组原位杂交的减数分裂/有丝分裂分析、RNA-Seq和病毒诱导的基因沉默（VIGS）介导的减数分裂候选基因分析，发现由于减数分裂稳定性的增强，耐逆性的遗传率与整倍体频率的增加一致。我们鉴定了一组候选减数分裂基因，这些基因在抗逆植物中的表达与对照相比发生了改变，但表达与普通小麦（cv Chinese Spring，CS）相似。我们证明了VIGS介导的CS中单个候选减数分裂基因的下调足以赋予模拟合成小麦的不稳定减数分裂表型。我们的研究结果表明，预先存在的减数分裂基因的遗传调节变化可能是作为逆境耐受性的一个支柱，这显着提高了合成小麦的减数分裂稳定性。我们的研究结果暗示了一个合理的假设，即六倍体小麦的减数分裂机制可能已经开始在其起始阶段进化。
Polyploidy is a prominent route to speciation in plants; however, this entails resolving the challenges of meiotic instability facing abrupt doubling of chromosome complement. This issue remains poorly understood.We subjected progenies of a synthetic hexaploid wheat, analogous to natural common wheat, but exhibiting extensive meiotic chromosome instability, to heat or salt stress. We selected stress-tolerant cohorts and generated their progenies under normal condition. We conducted fluorescent in situ hybridization/genomic in situ hybridization-based meiotic/mitotic analysis, RNA-Seq and virus-induced gene silencing (VIGS)-mediated assay of meiosis candidate genes.We show that heritability of stress tolerance concurred with increased euploidy frequency due to enhanced meiosis stability. We identified a set of candidate meiosis genes with altered expression in the stress-tolerant plants vs control, but the expression was similar to that of common wheat (cv Chinese Spring, CS). We demonstrate VIGS-mediated downregulation of individual candidate meiosis genes in CS is sufficient to confer an unstable meiosis phenotype mimicking the synthetic wheat.Our results suggest that heritable regulatory changes of preexisting meiosis genes may be hitchhiked as a spandrel of stress tolerance, which significantly improves meiosis stability in the synthetic wheat. Our findings implicate a plausible scenario that the meiosis machinery in hexaploid wheat may have already started to evolve at its onset stage.