Meiotic chromosome stability of a newly formed allohexaploid wheat is facilitated by selection under abiotic stress as a spandrel

作者：Bian, Yao; Yang, Chunwu; Ou, Xiufang; Zhang, Zhibin; Wang, Bin; Ma, Weiwei; Gong, Lei; Zhang, Huakun^*; Liu, Bao^*

来源：NEW PHYTOLOGIST, 2018, 220(1): 262-277.

DOI：10.1111/nph.15267

• abiotic stress
• gene expression
• meiosis
• polyploidy
• spandrel
• speciation
• Triticum aestivum
• virus-induced gene silencing (VIGS)

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.

• 出版日期2018-10
• 单位东北师范大学