Plant Growth Stimulatory Effect of Terrein and Its Mechanism of Action in Crops under Drought Stress

Drought is one of the most important factors that limit crop yield. In this study, the growth promotive activity of terrein, a microbial metabolite, on four selected agricultural plants (Vigna radiata,Brassica chinensis,Triticum aestivumandSorghum bicolor) under drought conditions was assessed via pot experiment. Terrein effectively stimulated the seedling growth of tested species and increased their fresh and dry weight at low concentrations (2 and 10 μg/mL), either applied as a seed soaking agent or a spray solution, especially on root growth. The maximum stimulatory effect on root growth was observed onB. chinensisseedlings (99.20%), on fresh weight was found onT. aestivumseedlings (97.23%), and on dry weight was discovered onV. radiataseedlings (58.33%), implying that this stimulatory effect was species-specific. Further study revealed that the application of terrein significantly raised the contents of GA3, IAA and CTK; meanwhile, MDA content declined significantly, whereas the activity of POD, CAT and SOD was boosted significantly, suggesting that terrein can stimulate plant growth by reducing the production of ROS. Our work is the first study focusing on terrein’s plant growth promotive activity, indicating terrein has the potential to be further explored as an environment-friendly growth regulator.Keywords:antioxidant system;biofertilizer;phytohormone;plant growth regulation;terrein