Zhou Cheng, Ma Zhongyou, Zhu Lin, Xiao Xin, Xie Yue, Zhu Jian, Wang Jianfei
School of Life Science and Technology, Tongji University, Shanghai 200092, China.
Key Laboratory of Bio-Organic Fertilizer Creation, Ministry of Agriculture, Anhui Science and Technology University, Bengbu 233100, China.
Int J Mol Sci. 2016 Jun 21;17(6):976. doi: 10.3390/ijms17060976.
Plant-growth-promoting rhizobacteria can improve plant growth, development, and stress adaptation. However, the underlying mechanisms are still largely unclear. We investigated the effects of Bacillus megaterium BOFC15 on Arabidopsis plants. BOFC15 produced and secreted spermidine (Spd), a type of polyamine (PA) that plays an important role in plant growth. Moreover, BOFC15 induced changes in the cellular PAs of plants that promoted an increase of free Spd and spermine levels. However, these effects were remarkably abolished by the addition of dicyclohexylamine (DCHA), a Spd biosynthetic inhibitor. Additionally, the inoculation with BOFC15 remarkably increased plant biomass, improved root system architecture, and augmented photosynthetic capacity. Inoculated plants also displayed stronger ability to tolerate drought stress than non-inoculated (control) plants. Abscisic acid (ABA) content was notably higher in the inoculated plants than in the control plants under drought stress and polyethylene glycol (PEG)-induced stress conditions. However, the BOFC15-induced ABA synthesis was markedly inhibited by DCHA. Thus, microbial Spd participated in the modulation of the ABA levels. The Spd-producing BOFC15 improved plant drought tolerance, which was associated with altered cellular ABA levels and activated adaptive responses.
促进植物生长的根际细菌可以改善植物的生长、发育和胁迫适应性。然而，其潜在机制仍 largely不清楚。我们研究了巨大芽孢杆菌BOFC15对拟南芥植物的影响。BOFC15产生并分泌亚精胺（Spd），一种在植物生长中起重要作用的多胺（PA）。此外，BOFC15诱导植物细胞内多胺发生变化，促进游离Spd和精胺水平升高。然而，添加Spd生物合成抑制剂二环己胺（DCHA）后，这些影响显著消除。此外，接种BOFC15显著增加了植物生物量，改善了根系结构，并增强了光合能力。接种的植物也比未接种（对照）的植物表现出更强的耐旱胁迫能力。在干旱胁迫和聚乙二醇（PEG）诱导的胁迫条件下，接种植物中的脱落酸（ABA）含量明显高于对照植物。然而，DCHA显著抑制了BOFC15诱导的ABA合成。因此，微生物Spd参与了ABA水平的调节。产生Spd的BOFC15提高了植物的耐旱性，这与细胞内ABA水平的改变和激活的适应性反应有关。
