Cadmium stimulated cooperation between bacterial endophytes and plant intrinsic detoxification mechanism in Lonicera japonica thunb

Due to the intimate association between plant physiology and metabolism, the internal colonizing microbe (endophytes) community must be adjusted to support plant productivity in response to cell damage in plants under stress. However, how endophytes coordinate their activities with plant intrinsic mechanisms such as antioxidative systems and detoxification pathways during Cd accumulation remains unknown. In this hydroponic pot study, we investigated how exposure of Lonicera japonica. thunb. to different levels of Cd (0.5, 2.5, 5, 10, and 20 mg kg(-1)) affected plant growth, metabolic pathways, and endophyte community structure and function. Although Cd accumulation increased at 5 mg kg(-1) Cd, the biomass and height of L. japonica increased in as-sociation with elevated endophyte-involved plant detoxification activities. Endophytes, such as Sphingomonas, Klenkia, and Modestobacter, expressed major antioxidative regulators (superoxide dismutase and ascorbate acid) to detoxify Cd in L. japonica. Furthermore, L. japonica and its endophytes synergistically regulated the toxic effects of Cd accumulation via multiple plant metabolic defensive pathways to increase resistance to metal -induced stress.

Automated summary

Due to the close relationship between plant physiology and metabolism, it is important to understand how endophytes coordinate with plant intrinsic mechanisms to support plant productivity under stress. This study investigated the impact of different levels of Cd exposure on the growth, metabolic pathways, and endophyte community structure and function in Lonicera japonica. The results showed that the endophytes expressed antioxidative regulators to detoxify Cd and increase plant resistance to metal-induced stress.