印度梨形孢对盐胁迫下水稻幼苗生长及抗氧化系统的影响

Effects of Piriformospora indica on the Growth and Antioxidant System of Rice Seedlings Under Salt Stress

【目的】探究印度梨形孢(Piriformospora indica)PI-020对盐胁迫下水稻幼苗生长、抗氧化相关酶活性及基因表达水平的影响。【方法】以不同浓度的PI-020菌丝体悬液接种南粳9108水培苗,显微镜观察及qPCR技术分析PI-020在水稻秧苗根系的定殖能力,并测定水稻叶片丙二醛(MDA)含量,分析水稻秧苗的表型参数、光合色素含量、抗氧化相关酶活性及基因表达的变化。【结果】与对照相比,盐胁迫条件下(100 mmol/L NaCl),PI-020定殖后,水稻叶片MDA含量显著降低。200倍菌丝体稀释液处理的效果最好,MDA含量减少了67.2%。PI-020定殖后,水稻株高、根长、叶面积、鲜质量和干质量分别增加了34.67%、23.62%、58.04%、59.53%和67.25%,与对照相比均差异显著;同时PI-020定殖还显著提高了叶片光合色素含量,抗氧化酶CAT、APX、POD活性及抗氧化相关基因OsCAT、OsAPX2、OsSOD的表达水平。【结论】印度梨形孢PI-020通过提高水稻幼苗抗氧化能力减少盐胁迫引起的氧化损伤,从而降低MDA含量,同时缓解光合色素的降解,保护了水稻光合系统,进而提高水稻耐盐性。

【Objective】This study aims to investigate the impact of Piriformospora indica PI-020 on rice seedling growth,antioxidant-related enzyme activities and gene expression levels in response to salt stress.【Method】Different concentrations of PI-020 mycelial suspensions were used to inoculate Nanjing 9108 hydroponic seedlings.The colonization ability of PI-020 in rice seedling roots was evaluated using a microscopy and qPCR.The malondialdehyde(MDA)content of rice leaves was determined,and changes of phenotypic parameters,photosynthetic pigment contents,antioxidant-related enzyme activities and gene expression levels in rice seedlings were analyzed.【Result】Under salt stress(100 mmol/L NaCl),PI-020 colonization significantly reduced the MDA content in rice leaves compared to the control.The 200-fold mycelial dilution was the most effective,resulting in a 67.2%decrease in MDA content.After PI-020 colonization,the plant height,root length,leaf area,fresh weight,and dry weight of rice seedlings significantly increased by 34.67%,23.62%,58.04%,59.53%,and 67.25%,respectively,compared to the control.Additionally,PI-020 colonization significantly increased the photosynthetic pigment contents,CAT,APX,POD activities,and the expression levels of antioxidant-related genes OsCAT,OsAPX2,and OsSOD in leaves.【Conclusion】P.indica PI-020 reduces the oxidative damage caused by salt stress through improving the antioxidant capacity of rice seedlings,thereby reducing the content of MDA,while alleviating the degradation of photosynthetic pigments,protecting the photosynthetic system.Consequently,it improves the salt tolerance of rice.