普通小麦不同优势杂交种及其亲本之间基因表达差异比较研究

Differential Gene Expression between Wheat Hybrids and Their Parental Inbreds in Seedling Leaves of Early and Vigorous Tillering Stages

为探讨小麦杂种优势形成的分子机理 ,本研究选用普通小麦品种 (系 ) 3338,6554和 2 4 10 TD及其强优势杂种 (3338× 6655)和弱优势杂种 (2 4 10 TD× 6555) ,采用 m RNA差异显示技术 ,对生长至三叶一心(即分蘖初期 )和产生二级分蘖时 (即分蘖盛期 )的幼苗叶片基因表达差异进行了比较研究。结果表明 ,小麦杂种一代苗期基因表达较亲本明显不同 ,表现为数量水平和质量水平上的差异 ,但与分蘖初期相比 ,小麦杂交种与亲本之间在分蘖盛期的基因表达差异更明显 ,并且在分蘖初期主要为量的表达差异 ,而生长至分蘖盛期时 ,质的表达差异比例显著增高 ,这表明小麦杂交种与亲本间的基因表达差异与发育时期有关。分析发现 ,强优势杂种 与其亲本间的差异表达基因比例明显高于弱优势杂种 。另外 ,无论分蘖初期或盛期 ,在强优势杂种组合 中 ,增强型和沉默型所占比例均明显高于弱优势杂种组合 ,而单亲表达减弱型比例则较杂种组合 低。本文还对 m

In order to study the molecular basis of wheat heterosis, differential display of mRNA was used to analyze the difference of gene expression between heterotic hybrid (3338×6554), nonheterotic hybrid (2410TD×6554) and their parental inbreds in seedling leaves of early and vigorous tillering stages. The results indicated that the patterns of gene expression alters obviously in hybrid F 1 as compared to their corresponding parents, but the number of differentially expressed genes between hybrids and their parental inbreds is dependent on developmental stages. There were more differentially expressed genes in vigorous tillering seedling leaves as compared with early tillering seedling leaves, more differentially expressed genes between heterotic hybrid and its parents were found. On the other hand, we found major difference of gene expreesion between hybrids and their parental inbreds in early tillering seedling leaves occurred in the quantitative level, but both qualitative and quantitative differences were obvious in vigorous tillering seedling leaves. There were higher percentage of overexpressed and inhibited types in heterotic hybrids than in nonheterotic hybrid, indicating that overexpressed and inhibited genes may play important roles in wheat heterosis and should be the emphasis for further study. The method of detecting Differential Display Reverse PCR products and the alteration of gene expression in hybrids as compared to their parental inbreds in relation to heterosis were also discussed.