不同浓度H2S和NO处理对草莓货架期腐烂抑制及抗氧化相关基因表达的影响

Effects of treatments of different H2S and NO concentrations on expressions of genes related to decay inhibition and antioxidation in strawberries during shelf life

  • 摘要: 【目的】探究硫化氢(H2S)和一氧化氮(NO)气体对草莓货架期腐烂抑制、抗氧化相关酶活性及相关基因表达的调控作用,筛选最佳处理浓度,为草莓采后保鲜提供技术支持。【方法】以红颜草莓为试材,分别采用不同浓度(50、100、200和400 μL/L)的H2S和NO进行单独熏蒸处理,以不经气体熏蒸处理为对照组(CK),在(20±0.5)℃条件下贮藏6 d,货架期定期测定果实腐烂率、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)和多酚氧化酶(PPO)活性及相关基因的相对表达量,并通过相关分析和主成分分析对各指标之间的关系进行综合分析。【结果】与CK组相比,所有H2S和NO处理均能抑制果实腐烂并提高抗氧化能力。其中200 μL/L H2S处理效果最明显,货架期第5 d时,CAT和APX活性分别达26.26 U/g和50.89 U/(g·min),分别是CK组的2.02和4.72倍,货架中后期(4~6 d)显著上调FaSODFaCATFaPODFaAPX基因相对表达量(P<0.05,下同),同时抑制FaPPO基因表达和PPO活性,有效延缓果实氧化伤害和褐变进程;货架期第6 d时,腐烂率仅24.25%,较CK组(91.67%)显著下降73.55%,且低于同浓度NO处理组(33.30%),果实色泽保持良好,无明显变化。相关分析结果显示,腐烂率与FaSODFaPPO基因相对表达量呈极显著正相关(P<0.01)。主成分分析综合得分表明,200 μL/L H2S处理在各项指标中表现最优,货架期间综合得分始终最高,具有最佳的综合调控效果。【结论】200 μL/L H2S处理在草莓货架期内表现出良好的品质调控能力,在激活抗氧化系统与延缓褐变方面具有良好协同作用,可作为延长草莓货架期的有效措施。

     

    Abstract: 【Objective】This study aimed to investigate the regulatory effects of hydrogen sulfide (H2S) and nitric oxide (NO) gases on enzyme activities related to decay inhibition and antioxidation as well as related gene expression in strawberries during shelf life for screening the optimal treatment concentration, thereby providing technical support for postharvest preservation of strawberries.【Method】The strawberry cultivar Hongyan was used as the experimental material. For the fumigation treatments, H2S and NO were applied separately at different concentrations (50, 100, 200, and 400 μL/L), and samples not subjected to any gas fumigation were used as the control (CK). The samples were stored at (20±0.5)℃ for 6 d, and the fruit decay rate, activities of superoxide dismutase (SOD), catalase (CAT),peroxidase (POD),ascorbate peroxidase (APX),and polyphenol oxidase (PPO),as well as the related relative expression of key genes were determined during shelf life. Correlation analysis and principal component analysis were performed to comprehensively analyze the relationships among the measured indicators.【Result】Compared with CK,all H2S and NO treatments inhibited decay and enhanced antioxidant capacity, and the 200 μL/L H2S treatment exhibited the greatest effects. At the 5th d of shelf life, CAT and APX activities reached 26.26 U/g and 50.89 U/(g·min),which were 2.02 and 4.72 times those of the CK. During the middle to late shelf life (4-6 d),the relative expression of FaSODFaCATFaPOD, and FaAPX was significantly up-regulated (P<0.05, the same below), while FaPPO gene expression and PPO activity were inhibited, which effectively delayed oxidative damage and browning process. At the 6th d of shelf life,the decay rate was only 24.25%, representing a decrease of 73.55% compared with the CK (91.67%), which was lower than that under the NO treatment of the same concentration (33.30%), and the fruit color remained well-preserved without obvious changes. Correlation analysis showed that the decay rate had extremely significantly positive correlations with the expression of FaSOD and FaPPO genes (P<0.01). Comprehensive scores of principal component analysis indicated that, the 200 μL/L H2S treatment exhibited the optimal performance across all indicators, as its comprehensive scores were the highest along the shelf life, proving it had the best comprehensive regulation effects.【Conclusion】The 200 μL/L H2S treatment exhibits superior quality regulation capability for strawberries during shelf life and has good synergistic effects for activating the antioxidant system and delaying browning, so it can be an effective measure for extending the shelf life of strawberries.

     

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