Ansary Waheda Rahman, Prince Ferdous Rezwan Khan, Haque Effi, Sultana Farzana, West Helen M, Rahman Mahbubur, Mondol Abdul Mojid, Akanda Abdul Mannan, Rahman Mahfuz, Clarke Michele L, Islam Tofazzal
Department of Biotechnology, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur 1706, Bangladesh.
School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK.
Z Naturforsch C J Biosci. 2018 Apr 25;73(5-6):247-256. doi: 10.1515/znc-2018-0002.
Plant growth-promoting bacteria that are also capable of suppressing plant pathogenic fungi play an important role in sustainable agriculture. There is a critical need for conducting research to discover, characterize and evaluate the efficacy of new strains of such bacteria in controlling highly aggressive plant pathogens. In this study, we isolated endophytic bacteria from medicinal plants of Bangladesh and evaluated their antagonistic capacity against an important phytopathogenic fungus Sclerotinia sclerotiorum. Growth-promoting effects of those isolates on cucumber and rice seedlings were also assessed. Among 16 morphologically distinct isolates, BDR-2, BRtL-2 and BCL-1 significantly inhibited the growth of S. sclerotiorum through induction of characteristic morphological alterations in hyphae and reduction of mycelial dry weight. When cucumber and rice seeds were treated with these endophytic bacteria, seven isolates (BCL-1, BDL-1, BRtL-2, BRtL-3, BDR-1, BDR-2 and BBoS-1) enhanced seed germination, seedling vigor, seedling growth and number of roots per plant at a varying level compared to untreated controls. All isolates produced high levels of indole-3-acetic acid (6 to 63 μg/mL) in vitro. Two most potential isolates, BDR-2 and BRtL-2, were identified as Bacillus amyloliquefaciens and B. subtilis, respectively, based on the 16S rRNA gene sequencing. These results suggest that endophytic Bacillus species from native medicinal plants have great potential for being used as natural plant growth promoter and biopesticides in sustainable crop production.
同时能够抑制植物病原真菌的植物促生细菌在可持续农业中发挥着重要作用。迫切需要开展研究来发现、表征和评估此类细菌新菌株在控制极具侵袭性的植物病原体方面的功效。在本研究中，我们从孟加拉国的药用植物中分离出内生细菌，并评估了它们对重要植物病原真菌核盘菌的拮抗能力。还评估了这些分离株对黄瓜和水稻幼苗的促生长作用。在16个形态不同的分离株中，BDR-2、BRtL-2和BCL-1通过诱导菌丝体出现特征性形态改变并降低菌丝体干重，显著抑制了核盘菌的生长。用这些内生细菌处理黄瓜和水稻种子后，与未处理的对照相比，7个分离株（BCL-1、BDL-1、BRtL-2、BRtL-3、BDR-1、BDR-2和BBoS-1）在不同程度上提高了种子发芽率、幼苗活力、幼苗生长和单株根数。所有分离株在体外均产生高水平的吲哚-3-乙酸（6至63μg/mL）。基于16S rRNA基因测序，两个最具潜力的分离株BDR-2和BRtL-2分别被鉴定为解淀粉芽孢杆菌和枯草芽孢杆菌。这些结果表明，来自本土药用植物的内生芽孢杆菌属物种在可持续作物生产中具有作为天然植物生长促进剂和生物农药的巨大潜力。
