Li Liang, Li Lei, Wang Xiaoyang, Zhu Pengyue, Wu Hongqing, Qi Shuting
School of Marine Science and Engineering, Hebei University of Technology, No.8 Guangrongdao, Tianjin 300130, China.
School of Marine Science and Engineering, Hebei University of Technology, No.8 Guangrongdao, Tianjin 300130, China.
Plant Physiol Biochem. 2017 Oct;119:211-223. doi: 10.1016/j.plaphy.2017.08.029. Epub 2017 Sep 1.
Piriformospora indica, a cultivable root endophytic fungus, induces growth promotion as well as biotic stress resistance and tolerance to abiotic stress in a broad range of host plants. In this study, the potential protection for M Medicago truncatula plants from salinity stress by P. indica was explored. The improved plant growth under severe saline condition was exhibited in P. indica-colonized lines. Moreover, the antioxidant enzymes activities and hyphae density in roots were increased by the endophyte under high salt concentration. Conversely, reduced malondialdehyde (MDA) activity, Na content and relative electrolyte conductivity (REC) were observed in P. indica colonized plants. Especially, osmoprotectant proline accumulated and the expression of Delta 1-Pyrroline-5-carboxylate synthetase gene (P5CS2) was induced. The defense related genes PR1 and PR10 and the transcription factors MtAlfin1-like and C2H2-type zinc finger protein MtZfp-c2h2 were induced by P. indica colonization as well. Further work indicated that salinity resistance was increased in overexpressing P5CS2, MtAlfin1-like and MtZfp-c2h2 transgenic M. truncatula plants. Interestingly, our data showed that the transcription factors MtAlfin1-like and MtZfp-c2h2 were positively contributed to P. indica colonization. These results demonstrate that tolerance to salinity stress was conferred by P. indica in M. truncatula via accumulation of osmoprotectant, stimulating antioxidant enzymes and the expression of defense-related genes. This work revealed the potential application of P. indica's as a plant growth-promoting fungus for the target improvement either in crop protection or in the salinized soil improvement indirectly.
印度梨形孢是一种可培养的根部内生真菌，能促进多种寄主植物的生长，增强其对生物胁迫的抗性以及对非生物胁迫的耐受性。在本研究中，探究了印度梨形孢对紫花苜蓿植株盐胁迫的潜在保护作用。在严重盐胁迫条件下，定殖有印度梨形孢的品系表现出植株生长得到改善。此外，在高盐浓度下，内生真菌使根中的抗氧化酶活性和菌丝密度增加。相反，在定殖有印度梨形孢的植株中，丙二醛（MDA）活性、钠含量和相对电导率（REC）降低。特别是，渗透保护剂脯氨酸积累，并且诱导了Δ1-吡咯啉-5-羧酸合成酶基因（P5CS2）的表达。定殖印度梨形孢还诱导了防御相关基因PR1和PR10以及转录因子MtAlfin1-like和C2H2型锌指蛋白MtZfp-c2h2的表达。进一步的研究表明，过表达P5CS2、MtAlfin1-like和MtZfp-c2h2的转基因紫花苜蓿植株的耐盐性增强。有趣的是，我们的数据表明转录因子MtAlfin1-like和MtZfp-c2h2对印度梨形孢的定殖有正向作用。这些结果表明，印度梨形孢通过积累渗透保护剂、刺激抗氧化酶以及防御相关基因的表达，赋予了紫花苜蓿对盐胁迫的耐受性。这项工作揭示了印度梨形孢作为一种促进植物生长的真菌在作物保护或间接改良盐渍土壤方面的潜在应用价值。
