β-氨基丁酸处理对采后草莓果实贮藏品质和内部还原势的影响

Effects of BABA treatment on the quality and redox property in postharvest strawberries

研究了10 mmol/Lβ-氨基丁酸(β-aminobutyric acid,BABA)、5 mmol/L 6-氨基烟酰胺(6-AN)以及两者复合处理对采后"丰香"草莓果实(Fragaria ananassa Duch. cv‘Fengxiang’)贮藏期间腐烂和品质的影响,并从还原势的角度探讨了BABA诱导果实抗病性的相关机理。结果表明,经10 mmol/L BABA处理的草莓果实中TSS、TA、总花色苷和总酚含量以及DPPH自由基清除率和总还原力在20℃下贮藏5 d后均显著高于对照水平,而果实发病率则显著低于对照水平。BABA处理可促进草莓果实中还原性信号分子NO和SA的积累,并诱导磷酸戊糖途径关键酶G6PDH和6PGDH活性的上升,从而促使果实中还原性物质NADPH和GSH大量生成并降低氧化性产物NADP+和GSSG含量,同时果实Fa PR1、Fa Chi3、Faβglu和Fa PAL等PRs基因表达量也显著上升。单一6-AN或6-AN+BABA处理则显著降低了果实中NO和SA的含量,抑制G6PDH和6PGDH活性以及NADPH和GSH的积累,经单一6-AN或6-AN+BABA处理的果实中PRs基因表达量也显著下降。通过这些结果可推测,草莓果实抗病性的形成与还原势的增长密切相关; BABA处理可直接诱导还原性信号分子的生成,并通过调控PPP途径关键酶活性以积累还原性物质,全面增强草莓果实内部还原势,诱导一系列PRs基因的表达,最终抑制了贮藏期间腐烂的发生并改善了果实综合品质。

The present study was performed to investigate the effects of BABA treatment on decay and quality of postharvest strawberries(Fragaria ananassa Duch.cv‘Fengxiang’)and the mechanism of pathogen resistance in respect to redox status.The results showed that compared with the control,the strawberries treated with 10 mmol/L BABA had higher contents of TSS,TA,total phenolics and anthocyanins as well as scavenging capacity against 1,1-diphenyl-2-picrylhydrazyl and reducing power.Moreover,the treated fruit showed lower disease rate.BABA could enhance the accumulation of reductive signal molecular NO and SA,and induce the enzyme activities of G6PDH and 6PGDH which are the key enzymes in pentose-phosphate pathway(PPP),to enhance the production of NADPH and GSH and lower the contents of NADP+and GSSG to improve internal redox status.Meanwhile,the expression levels of FaPR1,FaChi3,Faβglu and FaPAL in BABA-treated fruits increased during the stored period.The 6-AN treatment alone or in combination with BABA significantly lowered the contents of SA and NO,and inhibited the activities of G6PDH and 6PGDH and accumulation of NADPH and GSH.The fruits treated with 6-AN alone or 6-AN combined with BABA showed the decrease in PRs gene expressions.Therefore,it is found that 10 mmol/L BABA treatment can induce generating reductive signaling molecules and increase the activities of key enzymes in PPP to promote the reduction potential of the fruits and induced the expression of PRs gene to inhibit decay and improve overall quality of strawberries.