干旱胁迫下烟草脯氨酸杂种优势及相关基因差异表达分析

摘要

In order to explore the molecular genetic basis of proline heterosis in tobacco under drought stress, 7 tobacco varieties with different drought resistance and 10 hybrid combinations were used as materials, and drought stress treatments were set up to analyze proline heterosis and differential expression of related genes in tobacco by pot experiments. The results showed that the content of tobacco proline under drought stress increased continuously at the early stage and decreased after the 14th day. The heterosis of proline content in hybrid combinations was significantly different, and the proline content had the mid-parent heterosis with the highest value of 40.35 and the lowest of -51.66. The relative expression levels of the proline synthesis key enzyme genes P5CS and δ-OAT were significantly higher in the strong-dominant combinations, being 2.10 times and 1.87 times of those of the weak-dominant combinations,respectively.There was a significant positive correlation between the proline heterosis and P5CS gene relative expression after persistent drought for 7d at the vigorous growth stage. The correlations between the proline heterosis and δ-OAT gene relative expression were significant or extremely significant after persistent drought for 14d at the root extension stage and persistent drought for 7d and 14d at the vigorous growth, with correlation coefficients of 0.93, 0.98 and -0.96, respectively. Therefore, the up-regulation or down-regulation of δ-OAT and P5CS was the molecular basis for the formation of heterosis of tobacco proline content during the corresponding growth periods.%为探讨干旱胁迫下烟草脯氨酸杂种优势的分子遗传基础,以抗旱性差异较大的7个烟草品种及其组配的10个杂交组合为材料,采用盆栽试验设置干旱胁迫处理,进行了烟草脯氨酸杂种优势及其相关基因差异表达分析.结果表明,干旱胁迫下烟草脯氨酸含量在胁迫早期持续增加,第14天后开始下降;杂交组合间脯氨酸含量性状杂种优势差异明显,中亲优势最高40.35、最低?51.66;强优势组合中脯氨酸合成关键酶基因P5CS和δ-OAT相对表达量明显高于弱优势组合,分别是弱优势组合的2.10倍、1.87倍;脯氨酸杂种优势与P5CS基因相对表达量在旺长期持续干旱7 d时存在显著正相关关系,与δ-OAT基因相对表达量在伸根期持续干旱14 d、旺长期持续干旱7 d和14 d呈显著或极显著的相关关系,相关系数分别为0.93、0.98和?0.96.结果显示,脯氨酸合成关键酶基因δ-OAT和P5CS的时序性上调或下调表达是相应时期烟草脯氨酸含量性状杂种优势形成的分子基础.