Floral development of an asexual and female-like mutant carrying two deletions in gynoecium-suppressing and stamen-promoting functional regions on the Y chromosome of the dioecious plant Silene latifolia
Floral development of an asexual and female-like mutant carrying two deletions in gynoecium-suppressing and stamen-promoting functional regions on the Y chromosome of the dioecious plant Silene latifolia
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DOI：
10.1093/pcp/pcm113
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发表时间：
2007-10-01
影响因子：
4.9
通讯作者：
Kawano, Shigeyuki
中科院分区：
文献类型：
--
作者：
Koizumi, Ayako;Amanai, Yasuhito;Kawano, Shigeyuki
在雌雄异株植物宽叶蝇子草中，性二型是由Y染色体上的基因控制的。K 034是第一个同时具有雌花和无性花的突变体。其雄蕊完全被抑制，雌蕊群表现出两种抑制模式。一个雌蕊群类似于一个细杆，在野生型男性（无性花）;另一个是不完全抑制，有13心皮（雌花）。这些模式的比例为9：1。为了排除K 034中嵌合体的可能性，我们将K 034的雌性样花与野生型雄性杂交。从这种杂交获得的后代在一个个体中具有无性和雌性样花。这种二花型表型是不分离遗传的。为了研究K 034花器官的身份，我们用扫描电子显微镜和原位杂交技术分析了无性和雌性样花的发育，并以SLM 1和SLM 2（分别为AGAMOUS和PISTILLATA的直系同源物）为探针。K 034毛状根根尖染色体有丝分裂显示有25条染色体。荧光原位杂交分析表明，K 034具有两条X染色体和一条Y染色体（Y-d），其中Y-d染色体重排后丢失了拟常染色体区（PAR）。利用Y特异性序列标记位点（STS）进行PCR分析，明确了K 034的Y-d在雌蕊抑制区和雄蕊促进区有另外两个缺失。这是合理的建议，这些性染色体异常导致两个异常的性表型：无性和不完美的女性（女性样）花在K 034。
Sexual dimorphism is controlled by genes on the Y chromosome in the dioecious plant Silene latifolia. K034 is the first mutant with female flowers and asexual flowers in one individual. Its stamens are suppressed completely, and its gynoecium exhibits two suppression patterns. One gynoecium resembles a thin rod, as in wild-type males (asexual flower); the other is imperfectly suppressed, having 13 carpels (female-like flower). The ratio of these patterns was 9 : 1. To exclude the possibility of chimerism in K034, we crossed a female-like flower of K034 with a wild-type male. Progeny obtained from this crossing had asexual and female-like flowers in one individual. This two-flower-type phenotype was inherited without separating. To examine the identity of flower organs in K034, we analyzed the development of asexual and female-like flowers using scanning electron microscopy and in situ hybridization with SLM1 and SLM2(orthologs of AGAMOUS and PISTILLATA, respectively) as probes. Mitotic spreads of root tip chromosomes from hairy root cultures showed that K034 had 25 chromosomes. Fluorescent in situ hybridization analysis, using a subtelomeric repetitive sequence (KpnI subfamily) as a probe, indicated that K034 possessed two X chromosomes and one Y chromosome (Y-d), of which Y-d had been rearranged to lose the pseudoautosomal region (PAR). PCR analysis using Y-specific sequence-tagged site (STS) markers clarified that Y-d of K034 had two other deletions in gynoecium-suppressing and stamen-promoting regions. It is reasonable to suggest that these sex chromosomal abnormalities resulted in two abnormal sexual phenotypes: the asexual and imperfect female (female-like) flowers in K034.