小麦杂交种及其亲本拔节期根系基因差异表达与杂种优势关系的初步研究

Primary Study on the Relationship Between Differential Gene Expression Patterns in Roots at Jointing Stage and Heterosis in Agronomic Traits in a Wheat Diallel Cross

以一套小麦 4× 5双列杂交组合的根系为材料 ,利用mRNA差异显示技术结合重复PCR扩增 ,分析了拔节期杂种与其亲本根系间基因表达的差异 ,并与杂种的 10个农艺性状表现和杂种优势进行相关分析。cDNA 2次PCR重复扩增中可稳定出现的带 (992 .4条 )占总带数 (12 4 1条 )的 79.97%。统计结果显示 ,杂种和其亲本间存在显著的基因表达差异 ,可概括为双亲共沉默型 (W 1)、单亲表达沉默型 (W2 )、杂种特异表达型 (W3)和单亲表达一致型 (W 4 )这 4种差异表达类型 ,其所占比例分别为 6 .74 %、5 .93%、4 .38%和 10 .4 8%。相关分析发现 ,各种差异表达模式与杂种性状表现的相关中有 3个呈显著相关 ,与性状杂种优势的相关中则有 7个呈显著相关 ,其中双亲共沉默型 (W 1)和单亲表达沉默型 (W 2 )与主穗长和单株生物产量杂种优势均呈显著正相关 ,单亲表达一致型 (W4 )与千粒重杂种优势呈显著正相关。双亲共沉默型 (W 1)和杂种特异表达型 (W 3)与根冠比杂种优势呈显著正相关。以上研究结果表明 ,基因的差异表达与作物杂种优势的形成可能有密切关系。

The patterns of differential gene expression in roots between hybrids and their parent inbreds in a wheat 4×5 diallel cross were analyzed by using differential display. In order to ensure the creditability, duplicated PCR was conducted. By using 15 primer combinations, a total of 1 241 bands were displayed, and 79.97 %(992 out of 1 241) can be repeated, which showed DDRT PCR was a useful technique for gene expression analysis. Four types of differential expression patterns were detected between hybrids and their parents: bands expressed in both parents but not in F 1 (W1); bands expressed in one parent but not in F 1 and another parent (W2); bands expressed only in F 1 but not in both parents (W3); and bands expressed in one parent and F 1 but not in another parent (W4). Relationship between differential gene expression patterns and performance of hybrids and heterosis was evaluated by using data for DDRTs and 10 agronomic traits. Analysis showed that: W1 was negatively correlated with performance of plant height. W1 and W3 were positively correlated with performance of root/shoot. Patterns of differential gene expression were found to be significantly correlated with heterosis: W1 was positively correlated with heterosis in spike length, biomass and root/shoot, W2 was positively correlated with heterosis in spike length and biomass, W3 was found to be positively correlated with heterosis in root/shoot, and W4 was positively correlated with heterosis in 1000 kernel weight. These results indicate that differential expressed genes play an important role in heterosis.