To verify this hypothesis, the changing patterns of ABA content in plants were examined. As expectedly, a marked increase in ABA levels was observed in leaves and roots of non-inoculated plants as a consequence of saline–alkaline treatment. Also, the inoculated plants exhibited a great rise in ABA levels, displaying a similar pattern for the non-inoculated plants. However, more ABA accumulation was observed in the inoculated plants than the non-inoculated plants. Wei L.X. et al. (2015) have reported that ABA treatment can improve the tolerance of rice plants to alkaline stress. Hence, the SA03-induced ABA accumulation may be responsible for enhancing the adaptation of plants to saline–alkaline stress. We further examined if the inhibited ABA biosynthesis affected the SA03-induced stress responses in plants. When plants were treated with FLU, the inoculated plants exhibited similar phenotypes with the non-inoculated plants under saline–alkaline stress. Consistently, several physiological parameters such as photosynthesis and the accumulation of Na+, K+ and Fe were markedly altered in the inoculated plants under the stress, which indistinctly differed from the non-inoculated plants. Similar results are recently reported by Wei L.X. et al. (2015) in which FLU exposure markedly increases the degree of cell membrane injury and reduces relative water content under alkaline stress, indicating that ABA plays a vital role in mediating the adaptive responses of plants to alkaline stress. Additionally, qRT-PCR analyses revealed that FLU exposure pronouncedly down-regulated the transcription of some Fe acquisition- and Na+ transport-related genes, which was in accordance with the physiological parameters observed.