硫化氢与一氧化氮互作调控马铃薯耐铝性的生理及分子机制

Aluminum (Al) toxicity is the most important factor limiting crop growth in acidic soils. Al induces inhibition of root elongation and influences water and nutrient absorption, resulting in the loss of crop yield, thereby threatening the national food security. To conduct the study of Al tolerance mechanism in potato contributes to breed new potato varieties with high Al resistance. Although the studies have shown that hydrogen sulfide (H2S) or nitric oxide (NO) can alleviate Al toxicity in plants, the regulatory role and molecular mechanisms of the interaction between H2S and NO on plant Al tolerance have not been reported yet. In this study, two potato genotypes with different Al resistance were used as experimental materials. Through the combination method of plant physiology and biochemistry and molecular biology technology, the signal cross-talk relationship between H2S and NO under Al stress, the effect of Al-induced H2S production on the antioxidant system and cell wall properties in potato roots, the effect of the cross-talk between H2S and NO on Al-induced citrate secretion were all studied. The purpose of this study is to confirm that H2S and NO may be a key signal factor of potato response to Al stress, certify the interactions between H2S and NO under Al stress, and reveal the regulatory mechanism of the interactions between H2S and NO on potato Al tolerance. This study has an important significance for elucidating the molecular physiological mechanism of potato Al tolerance and developing the improvement of potato germplasm.

铝毒害是酸性土壤上限制作物生长最重要的障碍因子，铝抑制植物根系伸长生长，影响水分和养分吸收，造成作物减产，威胁国家粮食安全。开展马铃薯耐铝机理研究有助于培育耐铝性更强马铃薯新品种。虽然有研究表明硫化氢或一氧化氮缓解植物铝毒害，但关于硫化氢与一氧化氮互作对植物耐铝性的调控作用及其分子机制还不清楚。本研究以2个耐铝性差异显著的马铃薯基因型为实验材料，采用植物生理生化和分子生物学技术相结合方法，围绕铝胁迫下硫化氢与一氧化氮的信号互作关系、铝诱导产生的硫化氢对马铃薯根系抗氧化系统影响、铝诱导产生的硫化氢对马铃薯根尖细胞壁特性影响、硫化氢与一氧化氮互作对铝诱导柠檬酸分泌影响开展研究。以期证实硫化氢和一氧化氮可能是马铃薯铝胁迫响应的关键信号因子，明确铝胁迫下硫化氢与一氧化氮的互作关系，揭示硫化氢与一氧化氮互作对马铃薯耐铝性的调控作用规律，对阐明马铃薯耐铝的分子生理机制和开展马铃薯种质改良具有重要意义。

铝毒是南方酸性土壤上限制作物生长的重要因子，硫化氢或一氧化氮缓解植物铝毒害，但硫化氢与一氧化氮互作对马铃薯耐铝性的调控机制还不清楚。本项目以两个耐铝性差异显著的马铃薯基因型为材料，围绕铝胁迫下硫化氢与一氧化氮的信号互作关系、铝诱导产生的硫化氢对马铃薯根系抗氧化系统影响、铝诱导产生的硫化氢对马铃薯根尖细胞壁特性影响、硫化氢与一氧化氮互作对铝诱导柠檬酸分泌影响进行研究。结果表明：（1）铝诱导产生的一氧化氮可通过激活L-DES活性促进硫化氢的产生。不同马铃薯基因型根尖硫化氢对铝胁迫响应时间不同，铝胁迫下耐铝马铃薯品种硫化氢含量显著高于铝敏感马铃薯品种；（2）铝诱导产生的硫化氢诱导根系抗氧化酶活性和维持体内氧化还原平衡，减少根系活性氧积累，降低膜脂过氧化损伤程度，从而增强马铃薯耐铝性；（3）铝诱导产生的硫化氢可以通过下调StPME表达降低果胶甲酯酶活性，降低铝在细胞壁积累，从而缓解铝对马铃薯根系伸长的抑制；（4）铝诱导产生的硫化氢可以上调StH+-ATPase和StMATE1表达，促进根系分泌柠檬酸，从而增强马铃薯对铝毒的耐性。上述结果已经在Mol Biol Rep、Potato Res等刊物上发表SCI论文11篇，申请国家发明专利5项，获授权2项，计算机软件著作权2项，培养青年科技骨干1名和硕士研究生2名。本研究结果不仅充实了硫化氢与一氧化氮互作在植物响应铝胁迫中的调控作用，也为解决酸性土壤减产的生产实践提供理论依据。