牛心甘蓝蜡粉缺失突变体410M特征的研究

Studies on characteristics of a heart-shaped glossy cabbage mutants 410M

[目的]本文旨在探索牛心甘蓝蜡粉缺失突变体410M的特征和实际应用价值,以丰富甘蓝种质资源,加速新品种创制和改良。[方法]调查牛心甘蓝野生型材料410W和蜡粉缺失突变体410M的农艺性状,测定其营养品质;扫描电镜观察其叶表超微结构;以蜡粉缺失突变体材料410M(P1)与其野生型410W(P2)为亲本分别配制6世代群体,分析410M蜡粉缺失性状的遗传规律;筛选出14个在拟南芥中参与蜡粉合成、转运的基因,并利用实时荧光定量PCR对其在410W和410M中的表达模式进行分析。[结果]蜡粉缺失甘蓝叶色亮绿,突变体410M球叶和外叶的维生素C含量显著高于野生型;其他表型及主要营养成分与野生型无明显差异。叶表超微结构观察显示,突变体叶表面光滑,蜡粉严重缺失;野生型叶表蜡粉分布致密,晶体结构主要为片状和线状。对6世代群体分离比例进行χ~2检测,结果表明410M蜡粉缺失性状为隐性单基因遗传。在参与拟南芥蜡粉生物合成、转运的14个基因中,共有7个基因在野生型中的表达显著高于突变体。[结论]蜡粉缺失突变体410M遗传稳定,商品性好,为育种和蜡粉分子基础研究的优良材料。

[ Objectives ] To enrich the germplasm resources and promote the improvement of new varieties with desirable traits of cabbage,a heart-shaped glossy mutant 410M of cabbage was studied. [ Methods] The major nutritional components and phenotypic characterization of 410M plants were analyzed,and the wax amount and crystal structure were observed by scanning electron micro- graphs（SEM）. Then, to study the inheritance of glossy wax-less characteristic, F~, F2, BC1P~ and BCj P2 populations were obtained through crossing, selfing and back-crossing by 410M （mutant）and 410W （wild）plants. Lastly, the transcriptional profiles of 14 genes that were related to wax biosynthesis and transport in Arabidopsis were analyzed by real-time quantitative RT-PCR. [ Results ] 410M plants had a remarkable glossy surface phenotypic trait throughout their growth and development, and other phenotypes were indistin- guishable from those of 410W. There were no significant differences in content of the major nutritional components including protein, crude fiber,total sugar and dry matter between 410M and 410W except vitamin C content. The SEM analysis revealed a significant difference in the total wax amount between 410M and 410W plants,and the surface of mature leaves of 410W was covered by dense linear or columnar wax crystals on both the ventral and abaxial of the leaf blade. Conversely, the mature leave surface of 410M was almost devoid of wax crystals,with only a small portion of granule-like wax crystals present on the smooth wax film. Then, the F^s indicated that non-glossy leaves were dominant over glossy leaves. The genetic ratio of 3 non-glossy to 1 glossy was obtained in F2 generations, and the back-cross generation involving a glossy parent as the recurrent parent showed a ratio of 1 non-glossy to 1 glossy. So,the results of X2 test on the separated proportion proved that the trait of glossy wax-less was controlled by one pair of recessive gene. Lastly, our work also showed that some genes that were involved in wax biosynthesis, and export pathways were down-regulated in 410M,which could cause the glossy phenotype of mutant plants. [ Conclusions] 410M exhibited excellent comprehensive properties with remarkable and stable glossy phenotype, and belongs to a core heart-shaped parent for future cabbage breeding programs and molecular studies.