Root-knot nematodes (Meloidogyne spp.) are among the most important plant pathogens. Biological control is one of the safety and effective methods for control of these nematodes. The aim of the present study was the isolation and identification of endophytic bacteria from tomato fields in some areas of Iran in order to evaluate their biocontrol potential against root-knot nematode. In the present study, the population of Meloidogyne was collected from infected cucumber roots of a greenhouse, and the bacteria were isolated from tomato samples collected from the fields in West-Azarbaijan province of Iran. The effects of the bacterial isolates on hatching and mortality of nematode second-stage juveniles were evaluated, and the effects of six selected isolates on infection of a susceptible cultivar of tomato with nematode were evaluated under greenhouse conditions. The root-knot nematode was identified as Meloidogyne incognita. Results showed that the all isolates exhibited considerable inhibitory effects on nematode hatching. The bacterial isolates also caused the mortality of juveniles. Six bacterial isolates with notable biocontrol potential were selected, and supplementary experiments and molecular identification of selected bacterial isolates were performed. Isolates 1, 2, 5, 7, 10, and 11 were identified as follows: Bacillus wiedmannii (MW405861), Pseudoxantomonas mexicana (MW405860), Pseudomonas thivervalensis (MW405862), Serratia liquefaciens (MW405864), Pseudomonas chlororaphis (MW405863), and P. fluorescens (MW405825), respectively. Based on the results of the greenhouse experiment, the selected isolates exhibited good results in terms of reduction of galls and egg masses of nematode. However, B. wiedmannii and S. liquefaciens had the best results in reduction of all investigated factors compared to other isolates. P. mexicana, P. chlororaphis, and P. fluorescens resulted moderate effects. P. thivervalensis was less effective than the others and in some cases had no effect on nematode reduction. The results showed that endophytic bacteria are good candidates for management of root-knot nematodes. The use of such agents instead of chemicals will be very valuable to the control of nematodes.

中文翻译：

---

某些内生细菌在根结线虫根结线虫生物防治中的潜力

根结线虫（Meloidogyne spp。）是最重要的植物病原体之一。生物防治是控制这些线虫的安全和有效方法之一。本研究的目的是从伊朗某些地区的番茄田中分离和鉴定内生细菌，以评估其对根结线虫的生防潜力。在本研究中，从温室的受感染黄瓜根中收集了根结线虫种群，并从伊朗西阿塞拜疆省的田间收集的番茄样品中分离了细菌。评估了细菌分离物对线虫二级幼虫的孵化和死亡率的影响，并在温室条件下评估了六个分离株对番茄易感线虫感染的影响。根结线虫被鉴定为根结线虫。结果表明，所有分离物均对线虫孵化具有显着的抑制作用。细菌分离物也引起了幼虫的死亡。选择了六种具有显着生物防治潜力的细菌分离株，并对所选细菌分离株进行了补充实验和分子鉴定。分离物1、2、5、7、10和11的鉴定如下：维氏芽孢杆菌（MW405861），墨西哥假单胞菌（MW405860），thivervalensis假单胞菌（MW405862），液化粘质沙雷氏菌（MW405864），绿腐假单胞菌（MW405863）和分别为荧光素（MW405825）。根据温室试验的结果，选择的分离物在减少线虫的胆汁和卵量方面显示出良好的效果。但是，与其他分离株相比，维氏芽孢杆菌和液化链球菌在降低所有调查因子方面具有最佳结果。P. mexicana，P。chlororaphis和P.fluorescens产生中等效果。Thivervalensis的效果不如其他P. thivervalensis，而且在某些情况下对减少线虫没有影响。结果表明，内生细菌是处理根结线虫的良好候选者。用这种试剂代替化学药品对控制线虫将非常有价值。与其他分离株相比，液化真菌在减少所有调查因子方面取得了最佳结果。P. mexicana，P。chlororaphis和P.fluorescens产生中等效果。Thivervalensis的效果不如其他P. thivervalensis，而且在某些情况下对减少线虫没有影响。结果表明，内生细菌是处理根结线虫的良好候选者。用这种试剂代替化学药品对控制线虫将非常有价值。与其他分离株相比，液化真菌在减少所有调查因子方面取得了最佳结果。P. mexicana，P。chlororaphis和P.fluorescens产生中等效果。Thivervalensis的效果不如其他P. thivervalensis，而且在某些情况下对减少线虫没有影响。结果表明，内生细菌是处理根结线虫的良好候选者。用这种试剂代替化学药品对控制线虫将非常有价值。