| 摘要: |
| 【目的】研究干旱-复水的水分动态变化及品种遗传特性对小麦水孔蛋白基因PIP2表达的影响，揭示小麦生理抗旱性的分子机制。【方法】以抗旱性差异较大的2个小麦品种“陕合6号”（抗旱）和“郑引1号”（干旱敏感）为材料，于幼苗培养至8 d时，采用渗透势为-0.4 MPa的PEG-8000溶液模拟干旱胁迫处理，胁迫时间分别为0(对照),12,36,60 h，胁迫60 h后复水36 h。运用半定量RT-PCR方法，研究从干旱胁迫到复水的整个过程中，水孔蛋白基因PIP2在2种小麦根系中的动态差异表达情况，以及根系水导、叶片相对含水量、游离脯氨酸含量和细胞膜相对透性的变化。【结果】正常水分条件下，“郑引1号”中PIP2的表达水平高于“陕合6号”；而水分胁迫条件下，“陕合6号”中PIP2的表达量普遍高于“郑引1号”，且PIP2的表达随水分的动态变化在2个品种中均表现出明显的可塑性。水分胁迫初期（36 h内），“陕合6号”中PIP2的表达水平显著高于对照，至60 h时又逐渐降低至低于对照水平；而“郑引1号” PIP2的表达量随着水分胁迫时间延长持续降低，至60 h时几乎检测不到其表达。胁迫60 h后复水36 h，2个小麦品种中PIP2的表达量均有恢复，但“郑引1号”的净表达量仍未达到胁迫前的水平，而“陕合6号”则超过了胁迫前的水平，表现出补偿效应。 与干旱敏感品种“郑引1号”相比,干旱胁迫下抗旱品种“陕合6号”的高PIP2转录水平对应于植株较高的根系水导、叶片相对含水量和游离脯氨酸含量,同时具有较低的根系细胞膜相对透性。【结论】抗旱品种在水分胁迫初期诱导并维持较高的PIP2表达，复水后PIP2的补偿表达可能是其具有较高抗旱能力的重要机制之一。 |
| 关键词: 小麦 水孔蛋白 干旱 复水 遗传差异 |
| DOI： |
| 分类号: |
| 基金项目:西北农林科技大学基本科研业务费专项（QN2012021） |
|
| Genetic variation of aquaporin PIP2 gene expression in wheat against drought stress |
|
|
| Abstract: |
| 【Objective】Effects of water dynamic change and genetic variation on aquaporin PIP2 gene expression in wheat roots were studied to explore the molecular mechanism of wheat physiological drought resistance.【Method】8 d-old wheat genotypes,“Shaanhe 6” (drought tolerant) and“ Zhengyin 1 ”(drought sensitive),were subjected to PEG-8000 solution with osmotic potential of -0.4 MPa for 0(CK),12,36 and 60 h,respectively,before being re-watered for 36 h.The dynamic expressive differences of aquaporin gene PIP2 were assayed by a semi-quantative reverse transcription-PCR (RT-PCR),and the physiological response were determined simultaneous.【Result】The results indicated that PIP2 expression in root system presented a plastic characteristic for both wheat genotypes subjected to various water conditions.Under normal water conditions,PIP2 transcript of “Zhengyin 1” was higher than that of “Shaanhe 6”,while under osmotic stress,the expression profile was reversed.At the early stage of osmotic stress (within 36 h),the transcript of PIP2 of “Shaanhe 6” increased initially before gradually decreasing to lower than control value (stress for 60 h).However,the transcript of PIP2 of “Zhengyin 1” was always decreasing,and the value was close to zero when exposed to PEG solution for 60 h.After re-watering,the PIP2 transcripts of both genotypes returned significantly.The transcript of “Zhengyin 1” didn’t reach its control value,while that of “Shaanhe 6” completely recovered,even to higher than control value.Compared with drought sensitive genotype,the relatively higher PIP2 transcript in drought resistance genotype correspond to the higher root hydraulic conductivity,leaf water conditions,and free proline content and the lower ion leakage of plasma membrane.【Conclusion】Inducing and maintaining a relative higher PIP2 transcript in the initial stage of drought as well as a compensate expression pattern after re-watering maybe one of the measures for drought resistance wheat genotype to overcome adverse environment. |
| Key words: wheat aquaporin drought stress re-watering genetic difference |
