Root rot of common bean caused by Pythium aphanidermatum is a serious disease that causes significant losses to the production and yield of this crop. This study aimed to biocontrol the root rot disease of common bean using Bacillus subtilis HE18 and Pseudomonas fluorescens HE22 as effective bioagents and promote the growth of this plant. Using the in vitro dual culture assay, B. subtilis HE18 and P. fluorescens HE22 inhibited the radial growth of the pathogenic P. aphanidermatum by 67.95 and 48.39%, respectively. Chemical analysis of the cell-free filtrates of both bioagents using GC/MS demonstrated the production of twenty and thirteen volatile compounds by B. subtilis HE18 and P. fluorescens HE22, respectively, which may account for their significant antifungal efficacy. In the greenhouse, the application of a combination of both bio-inoculants displayed lower severity of pre- and post-emergence damping off and high plant survival, recording 10.1, 6.7, and 83.3%, respectively. The expression of the defense-related genes JERF3, GLU, and PR1, was examined in the treated plants using qPCR, where the highest upregulation levels were recorded for the infected plants that were treated with the combined biocontrol agents. Treating of the infected common bean with a combination of B. subtilis HE18 and P. fluorescens HE22 increased the activity levels of POD and PPO antioxidant enzymes and enhanced the phenol content. Combined treating of the infected plants with both bioagents increased the TSS to 14.15 °Brix, compared with the infected, untreated plants (7.05 °Brix). The dual application of both bioagents expressed a significant increment in Chl. a and b pigments, enhanced the levels of carotenoids, and increased the total pigments. Treating of the infected and control plants with both bio-inoculants caused an appreciable increment in the shoot height, root length, and shoot and dry weights, respectively. Moreover, the same treatment increased the pod weights, pod length and width, and the number of seeds pod⁻¹, in addition to the yield plant⁻¹. Finally, we concluded that both bioagents acted synergistically against the fungal pathogen, as they targeted multiple sites in the fungal cell and promoted the growth parameters and yields of the treated common bean plants.

由瓜果腐霉(Pythium aphanidermatum)引起的菜豆根腐病是一种严重的病害，给该作物的产量和产量造成重大损失。本研究旨在利用枯草芽孢杆菌HE18和荧光假单胞菌HE22作为有效生物制剂来生物防治菜豆根腐病并促进该植物的生长。利用体外双重培养测定，枯草芽孢杆菌HE18和荧光假单胞菌HE22分别抑制致病性瓜果假单胞菌的径向生长67.95%和48.39%。使用 GC/MS 对两种生物制剂的无细胞滤液进行的化学分析表明，枯草芽孢杆菌HE18 和荧光假单胞菌HE22 分别产生了 20 种和 13 种挥发性化合物，这可能是它们具有显着抗真菌功效的原因。在温室中，两种生物接种剂的组合施用显示出苗前和苗后猝倒病的严重程度较低，并且植物存活率较高，分别为 10.1%、6.7% 和 83.3%。使用 qPCR 检查处理植物中防御相关基因JERF3、 GLU 和PR1的表达，其中用组合生物防治剂处理的受感染植物记录了最高的上调水平。用枯草芽孢杆菌HE18 和荧光假单胞菌HE22组合处理受感染的菜豆，提高了 POD 和 PPO 抗氧化酶的活性水平，并提高了酚含量。与受感染的未处理植物 (7.05 °Brix) 相比，用两种生物制剂联合处理受感染植物，TSS 增加至 14.15 °Brix。两种生物制剂的双重应用均表现出叶绿素的显着增加。 a和b色素，提高类胡萝卜素的水平，并增加总色素。用两种生物接种剂处理受感染植物和对照植物分别导致芽高、根长以及芽重和干重显着增加。此外，除了产量植物^{-1之外，相同的处理还增加了荚果重量、荚果长度和宽度以及荚果-1}种子数量。最后，我们得出结论，两种生物制剂对真菌病原体具有协同作用，因为它们靶向真菌细胞中的多个位点，并促进经处理的菜豆植物的生长参数和产量。