A Y-encoded suppressor of feminization arose via lineage-specific duplication of a cytokinin response regulator in kiwifruit

First author: Takashi Akagi; Affiliations: Kyoto University (日本京都大学): Kyoto, Japan

Corresponding author: Takashi Akagi

Dioecy (雌雄异株), the presence of male and female flowers on distinct individuals, has evolved independently in multiple plant lineages and the genes involved in this differential development are just starting to be uncovered in a few species. Here, we used genomic approaches to investigate this pathway in kiwifruits (genus Actinidia猕猴桃). Genome-wide cataloging of male-specific subsequences, combined with transcriptome analysis, led to the identification of a type-C cytokinin response regulator as a potential sex determinant gene (性别决定基因) in this genus. Functional transgenic analyses in two model systems, Arabidopsis thalianaand Nicotiana tabacumindicated that this gene acts as a dominant suppressor of carpel development (心皮发育), prompting us to name it 'Shy Girl (SyGI)'. Evolutionary analyses in a panel of Actinidiaspecies revealed that SyGIis located in the Y-specific region of the genome and probably arose from a lineage-specific gene duplication. Comparisons with the duplicated autosomal (常染色体) counterpart, and with orthologs from other angiosperms, suggest that the SyGI-specific duplication and subsequent evolution of cis-elements may have played a key role in the acquisition of separate sexes in this species.

雌雄异株，即雄花、雌花分别开在不同的个体上，在多个植物支系中独立进化，而参与这个发育分化的基因也才刚刚开始在少数物种中被鉴定出来。本文利用基因组学的方法研究了猕猴桃中参与雌雄异株发育通路的基因。结合全基因组范围的雄性特异亚测序和转录组分析鉴定到了一个C类细胞分裂素响应调控子作为一个猕猴桃潜在性别决定基因。在拟南芥和烟草中的功能转基因分析显示该基因作为心皮发育的显性抑制子，因此作者将其命名为Shy Girl，缩写SyGI。对几个猕猴桃属物种的进化分析表明SyGI定位于基因组Y染色体特异的区域，可能起源于支系特异性的基因复制事件。通过与其在常染色体的旁系同源基因及其它被子植物中的直系同源基因的比较显示SyGI特异的复制和随后顺式元件的演化可能在该物种该性别决定基因的获取扮演重要的作用。

P.S. 同期评论文章：Shy Girl Gives Kiwifruit Male Flowers(http://www.plantcell.org/content/early/2018/04/06/tpc.18.00278)

通讯：Takashi Akagi (https://www.hakubi.kyoto-u.ac.jp/eng/02_mem/02akagi.shtml)

研究方向：利用基因组学等手段对水果作物进行遗传改良。

doi: https://doi.org/10.1105/tpc.17.00787

Journal: Plant Cell

First Published date: 06 April, 2018

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