Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, 610065, China.
Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, 610065, China.
Microb Pathog. 2022 Dec;173(Pt A):105858. doi: 10.1016/j.micpath.2022.105858. Epub 2022 Oct 29.
In this study, we investigated the antibacterial mechanism of forsythoside A against the kiwifruit canker pathogen, which provided the theoretical basis for the prevention and control of canker disease and the development of plant-based fungicides. The pathogenic bacteria were isolated from kiwifruit diseased tissues and the specific primers Psa_A1 F2 and Psa_A1 R1 were used for preliminary identification. Four pairs of housekeeping genes, including gapA, gltA, gyrB, and rpoD, were used for polygenic typing identification. The inhibition effect of forsythoside A on Psa was evaluated by the filter paper bacteriostasis method. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of Psa were determined by the 96-well plate absorbance and colony counts. The changes in Psa biofilm formation, motility, IAA synthesis, iron utilization, and respiratory chain dehydrogenase activity were determined. The Psa morphology was observed by Scanning electron microscope (SEM) and transmission electron microscope (TEM). The expression of some virulence genes was analyzed by qPCR. The results showed that the pathogen was Pseudomonas syringae pv. actinidiae(Psa). The inhibitory effect of forsythoside A on Psa was positively correlated with its concentration. while the MIC and MBC were 2.0 and 5.0 mg/mL, respectively. The biofilm formation and motility of Psa were not only obviously inhibited, but also the substance and energy metabolism were interfered, while obvious deformity and rupture of the cells were occurred in Psa Bacteria. In addition, The transcription of the Psa pathogenic genes was affected. The infection investigation of kiwifruit leaves indicated that forsythiaside A inhibits Psa pathogenicity and had a protective effect. This study concluded that forsythoside A has a certain control effect on kiwifruit canker, and has the potentiality to be developed as a novel plant fungicide.
在这项研究中，我们研究了连翘酯苷 A 对猕猴桃溃疡病病原菌的抗菌机制，为溃疡病的防治和植物源杀菌剂的开发提供了理论依据。病原菌从猕猴桃病组织中分离得到，采用特异引物 Psa_A1 F2 和 Psa_A1 R1 进行初步鉴定。采用 gapA、gltA、gyrB 和 rpoD 等 4 对管家基因进行多基因分型鉴定。采用滤纸片抑菌法评价连翘酯苷 A 对 Psa 的抑制效果。通过 96 孔板吸光度和菌落计数法测定 Psa 的最小抑菌浓度（MIC）和最小杀菌浓度（MBC）。测定 Psa 生物膜形成、运动性、IAA 合成、铁利用和呼吸链脱氢酶活性的变化。通过扫描电子显微镜（SEM）和透射电子显微镜（TEM）观察 Psa 形态。通过 qPCR 分析部分毒力基因的表达。结果表明，病原菌为丁香假单胞菌猕猴桃致病变种（Psa）。连翘酯苷 A 对 Psa 的抑制作用与其浓度呈正相关，MIC 和 MBC 分别为 2.0 和 5.0 mg/mL。Psa 的生物膜形成和运动性不仅明显受到抑制，而且物质和能量代谢受到干扰，同时 Psa 细菌出现明显的变形和破裂。此外，Psa 致病基因的转录受到影响。猕猴桃叶片的侵染调查表明，连翘酯苷 A 抑制 Psa 致病性并具有保护作用。本研究表明，连翘酯苷 A 对猕猴桃溃疡病具有一定的防治效果，具有开发为新型植物源杀菌剂的潜力。
