β-氨基丁酸抑制草莓低温贮藏过程中灰霉病的效果及其机理

Inhibitory Effect and Mechanisms of β-Aminobutyric Acid on Grey Mold(Botrytis cinerea) in Strawberry Fruits during Low Temperature Storage

以‘红颜’草莓为实验材料,研究β-氨基丁酸(β-aminobutyric acid,BABA)对草莓果实采后贮藏在低温((5±1)℃)条件下灰霉病的抑制效果及相关机理。草莓果实经过20 mmol/L的BABA处理后接种灰葡萄孢霉(Botrytis cinerea)孢子,然后在(5±1)℃的条件下贮藏12 d,结果发现BABA显著抑制了灰霉病的发生和病斑直径的扩展,与对照组相比,处理组几丁质酶(chitinase,CHI)和β-1,3-葡聚糖酶(β-1,3-glucanase,GLU)的活力分别提高了9.2%和54.9%,多聚半乳糖醛酸酶(polygalacturonase,PG)和纤维素酶(cellulose,Cel)的活力分别降低了29.3%和24.4%,同时,BABA提高了FaCHI和FaGLU基因的表达,抑制了FaPG和FaCel基因的表达;此外,体外实验的结果发现,BABA能够破坏灰葡萄孢霉孢子的质膜完整性,导致了孢子内部可溶性蛋白质和可溶性糖的泄漏。结果表明,BABA通过诱导抗病相关酶活力来提高抗病性、延缓果实软化并通过对病原菌的直接抑制作用减轻草莓果实采后灰霉病的发生。

The inhibitory effects of β-aminobutyric acid （BABA） on gray mold decay caused by Botrytis cinerea in harvested strawberry fruits stored at （5 ± 1） ℃ and the possible mechanisms were investigated. The strawberry fruits were pretreated with 20 mmol/L BABA, inoculated with the spores of Botrytis cinerea, and then stored at （5 ± 1） ℃ for 12 days. The results showed that the fruits treated with BABA had signi？cantly lower disease incidence and smaller lesion diameters than the control fruits. The fruits treated with BABA showed 9.2% higher activity of chitinase （CHI） and 54.9% higher activity of β-1,3-glucanase （GLU） than the control fruits at the end of storage. BABA-treated fruits showed 29.3% lower activity of polygalacturonase （PG） and 24.4% lower activity of cellulose （Cel） than the control fruits. BABA treatment upregulated the expression of FaCHI and FaGLU and downregulated the expression of FaPG and FaCel. Moreover, BABA damaged the plasma membrane integrity of B. cinerea spores and caused the leakage of protein and sugar from the pathogen mycelia in vitro. The results indicated that BABA could effectively inhibit gray mold decay in strawberry fruits, which may be related to increased defense-related enzyme activities in fruits, suppressed PG and Cel activities and direct fungitoxic property against the pathogen.