Badawy Ayat M
Botany and Microbiology Department, Faculty of Science, Menoufia University, Shebin El-Kom, 32513, Egypt.
Braz J Microbiol. 2024 Mar;55(1):749-757. doi: 10.1007/s42770-023-01204-x. Epub 2024 Jan 6.
Understanding the interactions within and between endophytes and their hosts is still obscure. Investigating endophytic bacterial plant growth-promoting (PGP) traits and co-inoculation effects on legumes' performance is a candidate. Endophytic bacteria were isolated from Vicia sativa root nodules. Such endophytes were screened for their PGP traits, hydrolytic enzymes, and antifungal activities. Sterilized Vicia faba and Pisum sativum seedlings were co-inoculated separately with seven different endophytic bacterial combinations before being planted under sterilized conditions. Later on, several growth-related traits were measured. Eleven endophytes (six rhizobia, two non-rhizobia, and three actinomycetes) could be isolated, and all of them were indole-acetic-acid (IAA) producers, while seven isolates could solubilize phosphorus, whereas three, five, five, and four isolates could produce protease, cellulase, amylase, and chitinase, respectively. Besides, some of these isolates possessed powerful antifungal abilities against six soil-borne pathogenic fungi. Co-inoculation of tested plants with endophytic bacterial mixes (Rhizobia+Actino+non-Rhizobia), (Rhizobia+Actino), or (Rhizobia+non-Rhizobia) significantly improved the studied growth parameters (shoot, root fresh and dry weights, length and yield traits) compared to controls, whereas co-inoculated plants with (Rhizobia), (non-Rhizobia), or (Actino) significantly recorded lower growth parameters. Five efficient endophytes were identified: Rhizobium leguminosarum bv. Viciae, Rhizobium pusense, Brevibacterium frigoritolerans, Streptomyces variabilis, and Streptomyces tendae. Such results suggested that these isolates could be utilized as biocontrols and biofertilizers to improve legumes productivity. Also, co-inoculation with different endophytic mixes is better than single inoculation, a strategy that should be commercially exploited.
目前对于内生菌与其宿主内部及之间相互作用的了解仍不清晰。研究内生细菌促进植物生长（PGP）的特性以及共接种对豆类植物性能的影响是一个研究方向。从野豌豆根瘤中分离出内生细菌。对这些内生菌进行了PGP特性、水解酶和抗真菌活性的筛选。在无菌条件下种植之前，将无菌的蚕豆和豌豆幼苗分别与七种不同的内生细菌组合进行共接种。随后，测量了几个与生长相关的特性。共分离出11种内生菌（6种根瘤菌、2种非根瘤菌和3种放线菌），它们均能产生吲哚乙酸（IAA），而7种分离物能溶解磷，3种、5种、5种和4种分离物分别能产生蛋白酶、纤维素酶、淀粉酶和几丁质酶。此外，其中一些分离物对六种土传致病真菌具有强大的抗真菌能力。与对照相比，将受试植物与内生细菌混合物（根瘤菌+放线菌+非根瘤菌）、（根瘤菌+放线菌）或（根瘤菌+非根瘤菌）共接种，显著改善了所研究的生长参数（地上部、根的鲜重和干重、长度及产量性状），而与（根瘤菌）、（非根瘤菌）或（放线菌）共接种的植物，其生长参数显著较低。鉴定出五种高效内生菌：豌豆根瘤菌蚕豆生物型、根瘤菌pusense、耐冷短杆菌、可变链霉菌和天蓝色链霉菌。这些结果表明，这些分离物可作为生物防治剂和生物肥料来提高豆类植物的生产力。此外，不同内生菌混合物共接种优于单一接种，这一策略应进行商业开发。
