干旱胁迫下披碱草属种间杂种F1的DNA甲基化MSAP分析

为了研究披碱草属种间杂种抗旱性优势的遗传机理，以加拿大披碱草（J1）、老芒麦(L1)及其种间杂种F₁为试验材料，经干旱胁迫处理，采用甲基化敏感扩增多态性（MSAP）方法，探究干旱胁迫后亲本及种间杂种F₁的DNA甲基化变化规律。结果表明，亲本材料L1和J1的DNA平均甲基化水平分别为45.41%和59.53%，杂种F₁的DNA甲基化水平为44.24%，说明杂种在形成过程中发生了DNA去甲基化作用。全甲基化在杂交种的DNA甲基化模式中占主导地位。干旱胁迫前亲本L1、J1和杂种F₁的DNA甲基化程度分别为32.73%、41.54%和28.00%，杂种F₁甲基化水平为亲本材料的75.40%；干旱胁迫后各材料的DNA甲基化程度均增加，平均增幅分别为14.99、20.44和19.78个百分点，说明干旱胁迫对不同材料DNA甲基化水平均有明显影响，且具有特异性。杂种F₁的抗旱性最强，其DNA甲基化水平低于亲本，说明杂交种的抗旱性与DNA甲基化水平存在一定的负相关。

MSAP Analysis of F1 DNA Methylation of Interspecific Hybrids of ElymusLinn. under Drought Stress

To understand the genetic mechanism of drought resistance heterosis in interspecific hybrids of the genus Elymus(Elymus canadensis,Elymus sibiricus and interspecific hybrids F₁), the methylation-sensitive amplification polymorphism (MSAP) was applied to explore the DNA methylation pattern caused by drought stress between the parents and interspecific hybrids F₁. The results showed that the average methylation levels of L1 and J1 of the parental materials were 45.41% and 59.53%; The methylation level of hybrid F₁ was 44.24%; The methylation level of hybrids was lower than that of parents; Demethylation occurred during the formation of hybrids, and total methylation dominated the methylation mode of hybrids. The methylation degree of parents L1 and J1 was 32.73% and 41.54%, respectively; The methylation degree of interspecific hybrid F₁ was 28.00%, and the interspecific hybrid F₁ was 75.40% of the methylation level of parental materials. The degree of DNA methylation of all materials increased under drought stress, with average increases of 14.99, 20.44, and 19.78 percentage points, respectively. This indicates that drought stress has a significant effect on the level of DNA methylation of different materials, which is also specific. The hybrid F₁ had the strongest drought resistance, and its DNA methylation level was lower than that of its parents, indicating that there was an inverse relationship between the drought resistance of hybrid species and the level of DNA methylation.