Abstract：Citrus sour rot is the common citrus (Citrus reticulata) postharvest disease which can cause fruit rot and acidity, seriously affect the storage effect. Microbial control of citrus acid rot has the advantages of being green, environmentally friendly, and no drug resistant, and is the direction for the healthy development of agriculture. In this study, the effect of Streptomyces pactum Act12 against the sour rot pathogen Geotrichum candidum was evaluated by plate confrontation culture method and growth rate method, the control effect was verified by acupuncture inoculation method, and the effects of filtrate on citrus resistant enzymes, resistant substances, and fruit quality were determined. The results showed that the inhibition rate of Act12 against Geotrichum candidum was 76.04%, and the inhibition rate of 20% fermentation filtrate against Geotrichum candidum reached 97.17%. Act12 had antibacterial activity against 8 types of pathogens derived from fruit. The filtrate significantly decreased the disease index of citrus sour rot (P<0.05), showing control effect of 88.20%. After treatment with 20% fermentation filtrate, the activities of fruit resistance enzymes - polyphenol oxidase (PPO), phenylalanine ammonia-lyase (PAL), chitinase (CHI), and glucanase (GLU), as well as the total phenolic and flavonoid content of the fruit peel were significantly increased (P<0.05), while the content of soluble solids and reducing sugars was significantly increased (P<0.05). The titratable acidity was significantly decreased (P<0.05), and the fruit quality was improved. This study provides theoretical reference and new resources for the biological control of postharvest sour rot in citrus fruits.
[1] 曹建康, 姜微波, 赵玉梅. 2007. 果蔬采后生理生化实验指导[M]. 北京: 中国轻工业出版社, pp. 29-43, 49-63, 104-105. (Cao J K, Jiang W B, Zhao Y M.2007. Experiment Guidance of Postharvest Physiology and Biochemistry of Fruits and Vegetables[M]. China Light Industry Press, Beijing, China, pp. 29-43, 49-63, 104-105.) [2] 方中达. 1998. 植病研究方法: 第3版[M]. 北京: 中国农业出版社, pp. 140-141. (Fang Z D.1998. Research Methods of Plant Diseases: 3rd ed[M]. China Agriculture Press, Beijing, China, pp. 140-141.) [3] 顾沛雯, 张光弟, 王华荣, 等. 2012. 果蔬采后致腐病菌检测及防治[J]. 农业科学研究, 33(01): 1-6. (Gu P W, Zhang G D, Wang H R, et al.2012. Determination and control of the main pathogens of post-harvest fruit and vegetables rot disease in Ningxia[J]. Journal of Agricultural Sciences, 33(01): 1-6). [4] 何斐, 张忠良, 崔鸣, 等. 2015. 链霉菌剂对魔芋的促生防病作用[J]. 应用与环境生物学报, 21(05): 866-871. (He F, Zhang Z L, Cui M, et al.2015. Growth promotion and disease prevention effects of Streptomyces on Amorphophallus konjac K. Koch ex N.E.Br[J]. Chinese Journal Application Environment Biology, 21(05): 866-871.) [5] 刘金丽, 卢丹, 姚佳, 等. 2024. 广谱拮抗放线菌S5-1的鉴定、发酵工艺优化及发酵粗提物抑菌活性评价[J/OL]. 微生物学通报, 1-21. ( Liu J L, Lu D, Yao J, et al.2024. Identification, fermentation condition optimization, and biocontrol ability of the crude fermentation extract of an antagonistic strain S5-1[J/OL]. Microbiology China, 1-21.) DOI: 10.13344/j.microbiol.china.230985. [6] 刘霞, 刘莉, 王鹏, 等. 2010. 罗伦隐球酵母对柑橘采后酸腐病的抑制效果[J]. 浙江师范大学学报(自然科学版), 33(01): 13-17. (Liu X, Liu L, Wang P, et al.2010. Efficacy of biological control sour rot of citrus fruit by Cryptococcus laurentii[J]. Journal of Zhejiang Normal University (Natural Science Edition), 33(01): 13-17.) [7] 田雪莲, 尹显慧, 龙友华, 等. 2017. 猕猴桃溃疡病菌拮抗菌筛选、鉴定及发酵条件优化[J]. 食品科学, 38(16): 79-85. (Tian X L, Yin X H, Long Y H.Screening, identification and optimization of fermentation conditions for antagonistic actinomycetes against Pseudomonas syringae pv. Actinidiae[J]. Food Science, 38(16): 79-85.) [8] 申光辉, 薛泉宏, 陈秦, 等. 2012. 硅酸钾与密旋链霉菌Act12菌剂配施对连作草莓生长、果实产量及品质的影响[J]. 中国生态农业学报, 20(03): 315-321. (Shen G H, Xue Q H, Chen Q, et al.2012. Effects of combined application of potassium silicate and Streptomyces pctum bio-control agents on growth, yield and quality of strawberry under continuous cropping in greenhouse[J]. Chinese Journal of Eco-Agriculture, 20(03): 315-321.) [9] 许英俊, 薛泉宏, 邢胜利, 等. 2007. 3株放线菌对草莓的促生作用及对PPO活性的影响[J]. 西北农业学报, 16(06): 146-153. (Xu Y J, Xue Q H, Xing S L, et al.2007. The growth promoting effect and induced endurance of three actimomyces strains to strawberry[J]. Acta Agriculturae Boreali-occidentalis Sinica, 16(06): 146-153.) [10] 张涵, 习慧君, 赵玉华, 等. 2021. 杨浦链霉菌WLU210的筛选、鉴定及其对苦瓜枯萎病的生防作用研究[J]. 中国生物防治学报, 37(05): 1058-1065. (Zhang H, Xi H J, Zhao Y H.2021. Screening, identification of Streptomyces yangpuensis wlu210 and its biocontrol effect on Fusarium wilt of bitter gourd[J].Chinese Journal of Biological Control, 37(05): 1058-1065.) [11] 张鸿雁, 薛泉宏, 申光辉, 等. 2013. 放线菌制剂对人参生长及根域土壤微生物区系的影响[J]. 应用生态学报, 24(08): 2287-2293. (Zhang H Y, Xue Q H, Shen G H, et al.2013. Effects of actinomycetes agent on ginseng growth and rhizosphere soil microflora[J]. Chinese Journal of Applied Ecology, 24(08): 2287-2293.) [12] 赵娟, 杜军志, 薛泉宏, 等. 2010. 3株放线菌对甜瓜幼苗的促生与抗性诱导作用[J]. 西北农林科技大学学报(自然科学版), 38(02): 109-116. (Zhao J, Du J Z, Xue Q H, et al.2010. The growth-promoting effect and resistance induction of 3 antagonistic actinomyces on Cucumis melo L.[J]. Journal of Northwest A&F University (Natural Science Edition), 38(02): 109-116.) [13] 赵娟, 薛泉宏, 王玲娜, 等. 2011. 多功能放线菌Act12对土传病原真菌的拮抗性及其鉴定[J]. 中国生态农业学报, 19(2): 394-398. (Zhao J, Xue Q H, Wang L N, et al.2011. Antagonistic effect of multifunctional actinomycete strain Act12 on soil-borne pathogenic fungi and its identification[J]. Chinese Journal of Eco-Agriculture, 19(2): 394-398) [14] 赵一洁, 唐毅, 王威浩, 等. 2017. 蜜橘酸腐病病原菌的分离鉴定以及不同抑菌剂处理对其控制效果[J]. 食品科学, 38(07): 230-237. (Zhao Y J, Tang Y, Wang W H, et al.2017. Isolation and identification of sour rot pathogen of Satsuma mandarin and inhibitory effects of three antifungal substances on it[J]. Food Science, 38(07): 230-237.) [15] 朱娜, 张树武, 徐秉良, 等. 2021. 解淀粉芽胞杆菌TS-1203对苹果炭疽叶枯病菌的抗生作用[J]. 植物保护, 47(04): 46-58. (Zhu N, Zhang S W, Xu B L, et al.2021. Inhibitory effects of Bacillus amyloliquefaciens TS-1203 on Glomerella cingulate[J]. Plant Protection, 47(04): 46-58.) [16] 朱志炎, 田志宏, 李建雄. 2019. 链霉菌的功能及其在农业上的应用[J]. 热带亚热带植物学报, 27(05): 580-590. (Zhu Z Y, Tian Z H, Li J X.2019. Function of Streptomyces and their application in agriculture[J]. Journal of Tropical and Subtropical Botany, 27(05): 580-590.) [17] Chen J, Xue Q H, Ma Y Q, et al.2020. Streptomyces pactum may control Phelipanche aegyptiaca in tomato[J]. Applied Soil Ecology, 146: 103369. [18] Eckert J W, Eaks I L.1989. Postharvest disorders and diseases of citrus fruits[J]. The Citrus Industry, 5: 179-260. [19] Ferraz L P, Cunha T D, Silva A C D, et al.2016. Biocontrol ability and putative mode of action of yeasts against Geotrichum citri-aurantii in citrus fruit[J]. Microbiological Research, 188-189: 72-79. [20] Hao W, Li H, Hu M, et al.2011. Integrated control of citrus green and blue mold and sour rot by Bacillus amyloliquefaciens in combination with tea saponin[J]. Postharvest Biology and Technology, 59(03): 316-323. [21] Hayman K A, Jugah K, Radziah O, et al, 2017. Plant growth-promoting abilities and biocontrol efficacy of Streptomyces sp. UPMRS4 against Pyricularia oryzae[J]. Biological Control, 112: 55-63. [22] Klein M N, Kupper K C.2018. Biofilm production by Aureobasidium pullulans improves biocontrol against sour rot in citrus[J]. Food Microbiology, 69: 1-10. [23] Lahlali R, Serrhini M N, Jijakli M H.2004. Efficacy assessment of Candida oleophila (strain O) and Pichia anomala (strain K) against major postharvest diseases of citrus fruits in Morocco[J]. Communications in Agricultural and Applied Biological Sciences, 69(04): 601-609. [24] Liu X, Fang W, Liu L, et al.2010. Biological control of postharvest sour rot of citrus by two antagonistic yeasts[J]. Letters in Applied Microbiology, 51(01): 30-35. [25] Ma G, Zhang L, Sugiura M, et al.2020. The Genus Citrus[M]. Sawston, Cambridge: Woodhead Publishing, pp. 495-511. [26] Muhammad F, Waseem R, Wei Z, et al.2015. Evaluation of the biocontrol potential of Streptomyces goshikiensis YCXU against Fusarium oxysporum f. sp. niveum[J]. Biological Control, 81: 101-110. [27] Strano M C, Altieri G, Admane N, et al.2017. Citrus Pathology[M]. Rijeka, Croatia, Intechopen, pp. 142-159. [28] Osman A, Abbase E, Mahgoubs, et al.2016. Inhibition of Penicillium digitatum in vitro and in postharvest orange fruit by a soy protein fraction containg mainly β-conglycinin[J]. Journal of General Plant Pathology, 82(06): 293-301. [29] Wang H X, Fu L, Meng J, et al.2022. Antagonistic activity and biocontrol effects of Streptomyces sp. CX3 cell-free supernatant against blueberry canker caused by Botryosphaeria dothidea[J/OL]. Crop Protection, 162: 1-44. [30] Wang L L, Wang N N, Guo D, et al.2023. Rhizobacteria helps to explain the enhanced efficiency of phytoextraction strengthened by Streptomyces pactum[J]. Journal of Environmental Sciences, 125: 73-81. [31] Wang S P, Ruan C Q, Yi L H, et al.2020. Biocontrol ability and action mechanism of Metschnikowia citriensis against Geotrichum citri-aurantii causing sour rot of postharvest citrus fruit[J]. Food Microbiology, 87: 103375. [32] Zhao Y S, Sun C Y, Wang S Z, et al.2023. Widely targeted metabolomic, transcriptomic, and metagenomic profiling reveal microbe-plant-metabolic reprogramming patterns mediated by Streptomyces pactum Act12 enhance the fruit quality of Capsicum annuum L[J]. Food Research International, 166: 112587.
