School of Applied Biosciences, College of Agriculture and Life Sciences, Kyungpook National University, Daegu, 701-702, Republic of Korea.
World J Microbiol Biotechnol. 2012 Apr;28(4):1483-94. doi: 10.1007/s11274-011-0950-9. Epub 2011 Nov 22.
Little is known about the role of endophytic fungi against abiotic stresses and isoflavonoids (IF) contents of soybean. In current study, we investigated the role of fungal endophytes on the growth of soybean under salt stress conditions. Pure cultures of nine endophytic fungi were isolated from the roots of field-grown soybean plants, and their culture filtrates were screened on Waito-C and Dongjin-byeo rice cultivars; for identification of plant growth promoting fungal strains. It was observed that fungal isolate GMC-2B significantly promoted the growth of both Waito-C and Dongjin-byeo. GMC-2B was later identified as a new strain of Metarhizium anisopliae LHL07 on the basis of 18S rDNA sequences and phylogenetic analysis. Metarhizium anisopliae LHL07 inoculated soybean plants recorded significantly higher shoot length, shoot fresh and dry biomass, chlorophyll contents, transpiration rate, photosynthetic rate and leaf area; under sodium chloride induced salt stress as compared to non-inoculated control plants. An elevated proline and reduced superoxide dismutase and malondialdehyde contents in M. anisopliae LHL07 inoculated soybean plants demonstrated mitigation of salt induced oxidative stress. Furthermore, reduced abscisic acid and elevated jasmonic acid contents in soybean plants confirmed that lesser stress was convened to M. anisopliae inoculated-plants under salinity stress. We also assessed the role of M. anisopliae interaction on IF biosynthesis of soybean, and found significantly higher IF contents in M. anisopliae inoculated soybean plants. In conclusion, endophytic fungal interactions with soybean can be beneficial to improve soybean quality and quantity under salt affected agricultural systems.
关于内生真菌在非生物胁迫和大豆异黄酮（IF）含量方面的作用知之甚少。在本研究中，我们研究了内生真菌在盐胁迫条件下对大豆生长的作用。从田间生长的大豆植株根部分离出九株内生真菌的纯培养物，并在 Waito-C 和 Dongjin-byeo 水稻品种上筛选其培养液，以鉴定具有促进植物生长的真菌菌株。观察到真菌分离株 GMC-2B 显著促进了 Waito-C 和 Dongjin-byeo 的生长。基于 18S rDNA 序列和系统发育分析，GMC-2B 后来被鉴定为新的金龟子绿僵菌 LHL07 菌株。与未接种对照植物相比，在氯化钠诱导盐胁迫下，接种金龟子绿僵菌 LHL07 的大豆植株的茎长、茎鲜重和干重、叶绿素含量、蒸腾速率、光合速率和叶面积显著增加。与未接种对照植物相比，接种金龟子绿僵菌 LHL07 的大豆植株中的脯氨酸含量升高，超氧化物歧化酶和丙二醛含量降低，表明盐诱导的氧化应激得到缓解。此外，大豆植株中的脱落酸含量降低，茉莉酸含量升高，证实了在盐胁迫下，接种金龟子绿僵菌的植物受到的胁迫较小。我们还评估了金龟子绿僵菌与大豆相互作用对 IF 生物合成的作用，发现接种金龟子绿僵菌的大豆植株中的 IF 含量显著升高。总之，内生真菌与大豆的相互作用有助于提高盐胁迫下农业系统中大豆的产量和质量。
