Yamada Kaori, Saraike Tatsunori, Shitsukawa Naoki, Hirabayashi Chizuru, Takumi Shigeo, Murai Koji
Department of Bioscience, Fukui Prefectural University, Eiheiji-cho, Fukui, Japan.
Plant Mol Biol. 2009 Sep;71(1-2):1-14. doi: 10.1007/s11103-009-9504-z. Epub 2009 Jun 2.
Homeotic transformation of stamens into pistil-like structures (pistillody) has been reported in cytoplasmic substitution (alloplasmic) lines of bread wheat (Triticum aestivum L.) that have the cytoplasm of a related wild species, Aegilops crassa. An ectopic ovule differentiates in the pistil-like stamen in the alloplasmic wheat. The SEEDSTICK (STK)-like class D MADS-box gene, wheat STK (WSTK), was expressed in the primordia of ectopic ovules in the pistil-like stamens as well as in the true pistil, suggesting that ectopic ovule formation results from WSTK expression in the pistil-like stamens of alloplasmic wheat. The ectopic ovule is abnormal as it fails to form complete integuments. Based on the expression pattern of WSTK and B(sister) MADS-box gene, WBsis (wheat B ( sister )), we conclude that WSTK plays a role in determination of ovule identity in the pistil-like stamen, but complete ovule development fails due to aberrant expression of WBsis.
在具有近缘野生物种粗山羊草（Aegilops crassa）细胞质的面包小麦（Triticum aestivum L.）细胞质替代（异质）系中，已报道雄蕊向雌蕊状结构的同源异型转变（雌蕊化）。在异质小麦的雌蕊状雄蕊中分化出一个异位胚珠。类种子棒（SEEDSTICK，STK）的D类MADS盒基因，小麦STK（WSTK），在雌蕊状雄蕊以及真正雌蕊的异位胚珠原基中表达，这表明异位胚珠的形成是由于WSTK在异质小麦雌蕊状雄蕊中的表达所致。异位胚珠是异常的，因为它不能形成完整的珠被。基于WSTK和B（姐妹）MADS盒基因WBsis（小麦B（姐妹））的表达模式，我们得出结论，WSTK在雌蕊状雄蕊中胚珠身份的确定中起作用，但由于WBsis的异常表达，胚珠的完全发育失败。
