珍珠粟（Pennisetum glaucum）内生芽孢杆菌的促植物生长和抗真菌活性。
Plant growth promoting and antifungal activity in endophytic Bacillus strains from pearl millet (Pennisetum glaucum).
机构信息
ICAR-National Bureau of Agriculturally Important Microorganisms (NBAIM), Mau, 275103, India.
AMITY Institute of Biotechnology, AMITY University Lucknow Campus, Lucknow, Uttar Pradesh, 226028, India.
出版信息
Braz J Microbiol. 2020 Mar;51(1):229-241. doi: 10.1007/s42770-019-00172-5. Epub 2019 Oct 22.
Bacterial endophytes are well known inhabitants of living plant system and perform important assignments in maintaining plant growth and health. Currently, limited reports are available on the endophytes of pearl millet (Pennisetum glaucum) reflecting antagonistic and plant growth promoting (PGP) attributes. Therefore, the major objectives of current investigation were to identify antagonistic strains of endophytic Bacillus from pearl millet and further illustrate their PGP capabilities. In this study, 19 endophytic Bacillus strains (EPP5, EPP21, EPP30, EPP32, EPP35, EPP42, EPP49, EPP55, EPP62, EPP65, EPP70, EPP71, EPP74, EPP78, EPP83, EPP86, EPP93, EPP100, and EPP102) displaying antagonistic activity towards Rhizoctonia solani (RS), Sclerotium rolfsii (SR), and Fusarium solani (FS) were isolated from different sections (root, leaf, stem, and root) of pearl millet. Phenotypic (shape, colony, gram staining reaction, endospore formation, and motility) and biochemical features (catalase, oxidase, citrate, gelatinase, urease, Voges Proskauer's, methyl red, indole, and nitrate reduction), along with the similarly comparison of 16S rRNA gene sequence with type strains identified eight antagonistic endophyhtes as B. amyloliquefaciens (EPP35, EPP 42, EPP62, and EPP 102), Bacillus subtilis subsp. subtilis (EPP65), and Bacillus cereus (EPP5, EPP71, and EPP74). The production of indole acetic acid and siderophores was varied among the isolated endophytes. Besides displaying enzymatic activities, these isolates varied in solubilizing capabilities of phosphate, potassium, and zinc. The presence of three antimicrobial peptide genes (ituD, bmyC, and srfA) also confirmed their antifungal nature. Further, single treatment of three promising strains (EPP5, EPP62, and EPP65) offered protection ranging from 35.68 to 45.74% under greenhouse conditions. However, microbial consortium (EPP5+ EPP62 + EPP65) provided the highest protection (71.96%) against root rot and wilt infection with significant increase in plant biomass. Overall, the current study indicated that pearl millet plant harbors various species of endophytic Bacillus that possess excellent biocontrol and growth promotion activities.
内生细菌是生活植物系统的著名居民，在维持植物生长和健康方面发挥着重要作用。目前，关于珍珠粟（Pennisetum glaucum）内生菌的报道有限，反映了其拮抗和促进植物生长（PGP）的特性。因此，本研究的主要目的是从珍珠粟中鉴定出具有拮抗作用的内生芽孢杆菌菌株，并进一步阐明其 PGP 能力。在这项研究中，从珍珠粟的不同部位（根、叶、茎和根）中分离出 19 株具有拮抗活性的内生芽孢杆菌（EPP5、EPP21、EPP30、EPP32、EPP35、EPP42、EPP49、EPP55、EPP62、EPP65、EPP70、EPP71、EPP74、EPP78、EPP83、EPP86、EPP93、EPP100 和 EPP102），这些菌株对 Rhizoctonia solani（RS）、Sclerotium rolfsii（SR）和 Fusarium solani（FS）表现出拮抗活性。通过表型（形状、菌落、革兰氏染色反应、内生孢子形成和运动性）和生化特征（过氧化氢酶、氧化酶、柠檬酸盐、明胶酶、脲酶、Voges Proskauer's、甲基红、吲哚和硝酸盐还原），以及与模式菌株的 16S rRNA 基因序列的相似性比较，将 8 株拮抗内生菌鉴定为解淀粉芽孢杆菌（EPP35、EPP42、EPP62 和 EPP102）、枯草芽孢杆菌亚种枯草芽孢杆菌（EPP65）和蜡状芽孢杆菌（EPP5、EPP71 和 EPP74）。分离内生菌的吲哚乙酸和铁载体的产量不同。除了表现出酶活性外，这些分离株在溶解磷酸盐、钾和锌的能力上也有所不同。三种抗菌肽基因（ituD、bmyC 和 srfA）的存在也证实了它们的抗真菌特性。进一步的，在温室条件下，三种有前途的菌株（EPP5、EPP62 和 EPP65）的单一处理提供了 35.68%至 45.74%的保护率。然而，微生物混合体（EPP5+EPP62+EPP65）提供了最高的保护率（71.96%），可防止根腐病和枯萎病感染，同时显著增加了植物生物量。总的来说，本研究表明，珍珠粟植物中含有多种具有优异生物防治和促进生长作用的内生芽孢杆菌。
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