Growth promotion and induction of antioxidant system of tomato seedlings (Solanum lycopersicum L.) by endophyte TPs-04 under low night temperature

•We tested PGPB on tomato seedlings growth under low night temperature.•Plants were adversely affected by night chilling stress.•PGPB enhanced plants growth and nutrient uptake.•Antioxidant system was induced by PGPB under night chilling stress.

This study investigated the effects of inoculation with selected 1-aminocyclopropane-1-carboxylate (ACC) deaminase-producing endophytic bacterium TPs-04 on growth promoting, nutrient uptake and antioxidant system of tomato (Solanum lycopersicum L.) seedlings under low night temperature (LNT, i.e., 6, 9 and 15 °C). Growth and nutrient uptake of tomato seedlings was reduced under different LNT stress level. Inoculation with strain TPs-04 significantly increased the length and dry weight of root and shoot, and chlorophyll content of leaves. Further analysis showed that it could enhance the uptake of N, P and K. The improvement of seedling growth might due to the plant growth promoting traits such as siderophore production, phosphorous solubilization, nitrogen fixation and ACC deaminase production indicated by TPs-04. Chilling stress resulted in rapid accumulation of hydrogen peroxide (H2O2) and malondialdehyde (MDA). Moreover, severe LNT (6 °C) raised the antioxidant enzyme activities compared to 9 and 15 °C treatments. The selected strain TPs-04 induced a higher increase in these antioxidant enzyme activities, and substantially decreased the accumulation of H2O2 and MDA in response to night chilling stress. Strain TPs-04 might be used as a potential bioinoculant of tomato plants protection under night chilling stress.