PDF(Pubmed)
Abstract：
Controlling early blight of tomatoes using endophytic bacteria is an eco-friendly and sustainable approach to manage this common fungal disease caused by Alternaria solani, Alternaria alternata, and Curvularia lunata. Endophytic bacteria are microorganisms that live inside plant tissues without causing harm and can help protect the host plant from pathogens. In this work, twenty endophytic bacterial isolates from tomato healthy plants were tested against pathogenic fungal isolates that caused early blight disease in vitro. Out of the 20 tested isolates, three (B4, B7, and B17) were considered effective isolates against the growth of fungal pathogens. The three isolates were recognized as Enterobacter cloacae HS-6 (B4), Pseudomonas gessardii HS-5 (B 7), and Pseudomonas mediterranea HS-4 (B17) using 16s-rDNA sequencing. Different concentrations of bacterial cultural diltrates at 20, 40, and 60% were tested for their antagonistic effects on the development of pathogenic fungi in vitro. The lowest dry weights of pathogenic isolates in all bacterial culture filtrates were discovered at 60%. In all culture filtrates, phenolic compounds showed the largest peak area. Under greenhouse conditions, the least disease severity of tomato early blight was found for E. cloacae and its culture filtrate compared to other treatments. Real-time PCR was used to examine the expression pattern of the defense response gene β-1.3 glucanase gene in infected tomato plants with pathogenic fungi (control) as well as its relations with efficient biocontrol agent (E. cloacae). The expression of the gene increased substantially and significantly after three days from the inoculation-infected plants with C. lunata and E. cloacae while it reached the maximum after five days from the inoculation with A. alternata, A. solani and E. cloacae. Our study concluded that the endophytic bacterial isolate E. cloacae can be considered a promising biocontrol agent for preventing tomato early blight.
摘要：
使用内生细菌控制番茄的早期疫病是一种生态友好且可持续的方法，可以管理由格格孢菌引起的这种常见真菌病，交替菌,还有弯孢菌.内生细菌是生活在植物组织内而不造成伤害的微生物，可以帮助保护宿主植物免受病原体的侵害。在这项工作中,从番茄健康植物中分离出的20株内生细菌对引起早期疫病的病原真菌进行了体外检测。在20个测试的分离株中，三个（B4，B7和B17）被认为是对抗真菌病原体生长的有效分离株。这三个分离株被识别为阴沟肠杆菌HS-6（B4），gessardii假单胞菌HS-5（B7），和地中海假单胞菌HS-4（B17）使用16s-rDNA测序。在体外测试了不同浓度的20、40和60％的细菌培养物扩张剂对病原真菌发育的拮抗作用。在所有细菌培养滤液中，致病性分离株的最低干重为60％。在所有培养滤液中，酚类化合物的峰面积最大。在温室条件下，与其他处理相比，阴沟肠球菌及其培养滤液的番茄早疫病的病情严重程度最低。实时PCR用于检查防御反应基因β-1.3葡聚糖酶基因在感染病原真菌（对照）的番茄植株中的表达模式及其与有效生物防治剂的关系（E。泄殖腔）。在接种C.lunata和E.cloacae感染的植物三天后，该基因的表达显着增加，而在接种A.alternata后五天达到最大值。A.solani和阴沟肠杆菌。我们的研究得出结论，内生细菌分离阴沟菌可以被认为是预防番茄早疫病的有前途的生物防治剂。
