中国农业科学 ›› 2022, Vol. 55 ›› Issue (4): 785-795.doi: 10.3864/j.issn.0578-1752.2022.04.013

• 食品科学与工程 • 上一篇    下一篇

褪黑素处理对梨果实采后黑斑病及贮藏品质的影响

向妙莲1(),吴帆1,李树成1,王印宝1,肖刘华1,彭文文1,陈金印1,2,陈明1()   

  1. 1江西农业大学农学院/江西省果蔬采后处理关键技术与质量安全协同创新中心/江西省果蔬保鲜与无损检测重点实验室,南昌 330045
    2萍乡学院,江西萍乡 337055
  • 收稿日期:2021-06-08 接受日期:2021-08-20 出版日期:2022-02-16 发布日期:2022-02-23
  • 通讯作者: 陈明
  • 作者简介:向妙莲,E-mail: mlxiang@jxau.edu.cn
  • 基金资助:
    国家自然科学基金(31360466);江西省自然科学基金(20192BAB204018);江西省果蔬采后处理关键技术及质量安全协同创新中心项目(JXGS-02)

Effects of Melatonin Treatment on Resistance to Black Spot and Postharvest Storage Quality of Pear Fruit

XIANG MiaoLian1(),WU Fan1,LI ShuCheng1,WANG YinBao1,XIAO LiuHua1,PENG WenWen1,CHEN JinYin1,2,CHEN Ming1()   

  1. 1College of Agronomy, Jiangxi Agricultural University/Collaborative Innovation Center of Postharvest Key Technology and Quality Safety of Fruits and Vegetables in Jiangxi Province/Jiangxi Key Laboratory for Postharvest Technology and Non-destructive Testing of Fruits & Vegetables, Nanchang 330045
    2Pingxiang University, Pingxiang 337055, Jiangxi
  • Received:2021-06-08 Accepted:2021-08-20 Online:2022-02-16 Published:2022-02-23
  • Contact: Ming CHEN

摘要:

【目的】 探究褪黑素(Melatonine,MT)处理对梨果实采后黑斑病及贮藏品质的影响,为外源物质调控果实抗采后病害及贮藏品质提供理论依据和参考。【方法】 以‘翠冠’梨果实为试验材料,喷施0.1 mmol·L-1 MT溶液置室温,48 h后沿梨果实赤道两侧刺直径1 mm、深度3 mm大小两个小孔,待伤口晾干后注入20 µL浓度为1.0×106 spores/mL黑斑病菌(Alternaria alternata)孢子悬浮液,以无菌水处理作为对照。接种后果实置于25℃,分析梨果实病斑直径、诱导效果及过氧化氢酶(PpCAT)、过氧化物酶(PpPOD多酚氧化酶(PpPPO)、铜-锌超氧化物歧化酶(Cu-ZnSOD)等防御酶相关基因和几丁质酶(PpCHI)、β-1, 3葡聚糖酶(PpGLU)等病程相关基因的表达量,研究MT诱导梨果实抗黑斑病的效应和机理。此外,梨果实喷施0.1 mmol·L-1 MT溶液晾干后于(5±1)℃、相对湿度85%—90%贮藏42 d,以无菌水处理为对照,定期测定果实腐烂率、失重率、呼吸强度、硬度、可溶性固形物、可滴定酸、维生素C、总酚和丙二醛含量,从而探讨MT处理对梨果实贮藏效果和品质的影响。【结果】 梨果实接种A. alternata后,病斑直径随接种时间延长而逐渐增大,MT处理组果实病斑直径显著小于对照组(P<0.05),接种后第3、5和7天,MT对梨果实抗黑斑病的诱导效应分别为29.16%、45.03%和23.26%;梨果实PpCATPpPOD、PpPPOCu-ZnSOD、PpCHIPpGLU相对表达量在接种后第4—7天均显著高于对照,最大值分别为对照的1.35、2.08、2.28、2.02、2.89和3.45倍,其中PpPOD、PpPPOPpCHI在接种后第1—6天表达量持续上升,且MT处理可显著提高表达量,表明MT处理诱导梨果实抗黑斑病可能与其提高防御酶基因和病程相关蛋白基因表达密切相关。在低温贮藏期间,MT处理组果实腐烂率与对照组差异不显著,或因病原菌在低温下生长受到抑制,果实腐烂降低;梨果实硬度在贮藏期内逐渐下降,但MT处理组果实硬度均高于对照组,在28 d时差异显著,MT处理组为对照组的1.06倍;梨果实呼吸强度在贮藏前期(7—14 d)上升后下降,但与对照组相比,MT处理抑制果实呼吸强度,延缓果实衰老的效果在贮藏前期较后期更明显;此外,MT处理也可显著降低果实失重率,维持较高水平的可溶性固形物,延缓可滴定酸和维生素C降解,同时促进果实总酚含量积累,增强果实抗氧化能力,抑制MDA含量积累,减轻细胞膜脂过氧化伤害。以上结果揭示MT可能通过调节梨果实糖、酸和细胞壁代谢,从而增强果实品质与耐贮性。【结论】 0.1 mmol·L-1 MT处理诱导了梨果实对采后黑斑病的抗性,激发了果实防御酶和病程相关蛋白基因的表达,且能显著提高梨果实贮藏品质。

关键词: 褪黑素, 梨, 果实, 黑斑病, 诱导抗性, 贮藏品质

Abstract:

【Objective】 The aim of this study was to explore the effects of melatonine (MT) treatment on postharvest black spot disease and storage quality of pear fruit, so as to provide the theoretical basis and reference for exogenous substances regulating postharvest disease and storage quality of pear fruit. 【Method】 ‘Cuiguan’ pears were used as the experimental material, which were sprayed with 0.1 mmol·L-1 MT solution and then kept at room temperature for 48 h. The treated fruits were inoculated with two 1 mm diameter × 3 mm depth small holes along both sides of the fruit equator. Twenty µL Alternaria alternata spore suspension with 1.0×106 spores/mL were injected into the two holes, and the sterile water treatment was used as control. The fruit was placed at 25℃ after inoculation, and then the lesion diameters and induced effects as well as the genes expression of defense enzymes, such as catalase (PpCAT), peroxidase (PpPOD), polyphenol oxidase (PpPPO), and copper-zinc superoxide dismutase (Cu-ZnSOD), and pathogenesis-related protein including chitinase (PpCHI) and β-1,3 glucanase (PpGLU), were analysed to demonstrate the effect and mechanism of MT-induced pear fruit against black spot disease. In addition, the pear fruits were sprayed with 0.1 mmol·L-1 MT solution, and then stored at (5±1)℃, 85%-90% relative humidity for 42 d. The sterile water treatment was used as the control. The decay rate, weight loss rate, respiration rate, firmness, total soluble solids, titratable acid, vitamin C, total phenols and malondialdehyde contents were measured at fixed period, and the effect of MT treatment on the storage effect and quality of pear fruit were discussed. 【Result】 The lesion diameters of pear fruits inoculated with A. alternata gradually increased with the time, while the lesion diameters under MT treatment was significantly smaller than those under the control (P<0.05). The MT-induced resistance effects on pear fruits black spot were 29.16%, 45.03% and 23.26% on the 3rd, 5th and 7th day, respectively. The relative expression levels of PpCAT, PpPOD, PpPPO, Cu-ZnSOD, PpCHI and PpGLU in MT-treated group were significantly higher than those of the control group during 4-7 days post inoculation (dpi), and the maximum values of them were 1.35, 2.08, 2.28, 2.02, 2.89 and 3.45 times of control fruits, respectively. The induced expression of PpPOD, PpPPO and PpCHI indicated that MT treatment inducing resistance of pear fruit to black spot disease possible depended on these defense enzyme and pathogenesis-related proteins. For the low temperature storage, the fruit decay rate was not significantly different between MT treatment group and control group, which was probably caused by the inhibition growth of pathogen under low temperature. All of fruit firmness gradually decreased during storage, while the fruit firmness under MT treatment was higher than that under the control with 1.06 times of significant difference at 28 d. Furthermore, the fruit respiration rate increased in the early storage stage (7-14 d) and decreased in the later stage. In comparison with the control group, the effects of MT treatment inhibiting fruit respiration and delaying fruit senescence were more significantly in the early storage stage than in the later stage. In addition, MT treatment also significantly reduced the fruit weight loss rate, maintained the high levels of total soluble solids, and delayed the degradation of titratable acid and vitamin C. Also, it promoted the accumulation of total phenolic content, enhanced the fruit antioxidant capacity, inhibited the accumulation of MDA content, and reduced the damage of cell membrane lipid peroxidation. The above results indicated that MT might enhance fruit quality and storage resistance by regulating fruit sugar, acid, and cell wall metabolism. 【Conclusion】0.1 mmol·L-1 MT treatment induced the resistance of pear fruit to black spot, stimulated the relative expression of defense enzymes and pathogenesis-related protein coded-genes, and finally improved the storage quality of pear fruit.

Key words: melatonin, pear, fruit, black spot, induced resistance, storage quality