芸苔属植物CAL基因的结构特征与花球的形态遗传

Structural Characters of CAL Genes and Morphological Genetics of Curd in Brassica Species

从花椰菜变种 (BrassicaoleraceaL .var.botrytis)中分离出 4种花球类型的纯合株系 :光滑型花球curd_s、毛状物花球curd_h、颗粒状花球curd_c和刺状物花球curd_t。用PCR方法分别扩增各株系的BobCAL基因并分析其中的部分序列 ,发现 4种株系的CAL基因在第五个外显子中都有AAG向TAG的终止突变 ,而且该终止密码子上游 6 38bp的DNA序列完全一致 ,说明花蕾、茎生叶等花球附生物的形态发生不是BobCAL的单一调节作用。花椰菜与结球甘蓝 (B .oleraceavar.capitata)和青花菜 (B .oleraceavar.italica)杂交后其F1代植株都失去了原有花球的形态特征 ,表现出花序的多态性 ,从而显示了不同变种CAL相互作用的形态学差异。从大白菜中分离出CAL的同源基因 ,发现BcpCAL基因没有发生终止突变。分析了从大白菜 (B .campestrisL .ssp .pekinensis)中分离出的BcpCAL的基因结构特征以及与其他基因间的同源性。为了解CAL基因的生物学功能 ,研究花球形态发生的机制提供了分子和遗传证据。

Cauliflower curd is composed structurally of a number of shortened shoots on which there are tremendous amount of naked apical meristems. The authors isolated four pure lines of different curd types from cauliflower (Brassica oleracea L. var. botrytis) accessions: smooth curd (curd_s), haired curd (curd_h), crystal curd (curd_c) and thorned curd (curd_t). BobCAL genes was cloned separately from each pure line by PCR amplification and a termination mutation from AAG to TAG was found in the fifth exon of all four sequences, whereas DNA sequences of 638 bp upstream of the stop codons were identical, demonstrating that BobCAL is not the sole regulator of flower buds and cauline on curd. After crosses of cauliflower with cabbage (B.oleracea var. capitata) or broccoli (B.oleracea var. italica), the resultant F 1 plants failed to form curd and had the diversity of inflorescence which implicates the relatedness of CAL to other regulators. One homologous gene of CAL, BcpCAL was isolated from Chinese cabbage (B.campestris L. ssp. pekinensis) and it was found not to have the termination mutation in the fifth exon, and thus the structure of BcpCAL gene was analyzed. The results offer molecular and genetic evidence for the study of biological function of CAL and morphological genetics of curd.