Comparison of using plant growth promoting bacteria and exogenous indole acetic acid on rice under ozone stress

Plant growth promoting bacteria (PGPB) could mitigate plants under abiotic stress by influencing plant physiology and adaptation tolerance to stress. In this study, the aims are compared three strains of PGPB (Bacillus thuringensis, Lysinibacillus sp. N5 and Bacillussp. N7) inoculation and both exogenous 5 μM and 10 μM IAA and compare the application of seed inoculation of PGPB and IAA and soil inoculation of PGPB/foliar spraying IAA on improving rice productivity under ozone stress. Ozone affected on rice productivity by decreasing AsA due to increasing malondialdehyde (MDA). Rice inoculated with PGPB and foliar spraying 5 μM IAA could lower MDA via enhancing IAA, AsA, and chlorophyll content. Nevertheless, improving rice productivity (grain yield and 100-grain weight) were found in both seed and soil inoculation of PGPB and applying seed inoculation of IAA5 and 10 μM. Therefore, both seed and soil inoculation of PGPB and seed inoculation of IAA were the best way for applying in rice under long-term ozone exposure.