Tartary buckwheat rice-type cultivars, which allow easy dehulling, lacked periclinal cell divisions that proceed underneath the epidermis in the proximity of ovary midribs in non-rice-type cultivars. The easy dehulling in these cultivars was associated with a G→A substitution in an AGAMOUS ortholog. Ease of dehulling in Tartary buckwheat (Fagopyrum tataricum) can affect the quality of its products. Tartary buckwheat cultivars that allow easy dehulling are called rice-type cultivars. The rice and non-rice hull types are determined by a single gene, but this gene is unclear. Here, we show that cells underneath the epidermis in the proximity of ovary midribs undergo periclinal cell divisions in non-rice-type cultivars but do not in a rice-type cultivar. The cells that arose from the periclinal cell divisions later underwent lignification, which should increase mechanical strength of hulls. In RNA sequencing, a partial mRNA of an AGAMOUS ortholog in Tartary buckwheat (FtAG) was found to be absent in the rice-type cultivar. Cloning of this gene revealed that this is a 42-bp deletion due to a G→A substitution at a splice acceptor site in the FtAG genomic region. In F2 progeny derived from a cross between non-rice-type and rice-type cultivars, all the rice-type plants exhibited the homozygous A/A allele at this site, whereas all the Tartary-type plants exhibited either the homozygous G/G allele or the heterozygous A/G allele. These results suggest that FtAG is a candidate for the gene that determines ease of dehulling in Tartary buckwheat. The DNA marker that we developed to distinguish the FtAG alleles can be useful in breeding Tartary buckwheat cultivars.

中文翻译：

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推定的 AGAMOUS 直系同源物是决定苦荞 (Fagopyrum tataricum) 脱壳难易度的基因的候选者

苦荞水稻型品种易于脱壳，但在非水稻型品种的子房中脉附近，缺乏在表皮下方进行的斜周细胞分裂。这些品种的容易脱壳与 AGAMOUS 直系同源物中的 G→A 取代有关。苦荞 (Fagopyrum tataricum) 容易脱皮会影响其产品的质量。容易脱壳的苦荞品种称为水稻型品种。水稻和非稻壳类型由单个基因决定，但该基因尚不清楚。在这里，我们展示了卵巢中脉附近表皮下方的细胞在非水稻品种中经历了周细胞分裂，但在水稻品种中则没有。由斜周细胞分裂产生的细胞后来经历了木质化，这应该会增加船体的机械强度。在 RNA 测序中，发现苦荞 (FtAG) 中 AGAMOUS 直系同源物的部分 mRNA 在水稻型品种中不存在。该基因的克隆表明这是一个 42 bp 的缺失，这是由于 FtAG 基因组区域中剪接受体位点的 G→A 取代所致。在来自非水稻型和水稻型品种杂交的 F2 后代中，所有水稻型植物在该位点都表现出纯合 A/A 等位基因，而所有鞑靼型植物​​都表现出纯合 G/G等位基因或杂合 A/G 等位基因。这些结果表明，FtAG 是决定苦荞脱壳难易度的基因的候选者。我们开发的用于区分 FtAG 等位基因的 DNA 标记可用于培育苦荞品种。