Transcriptome profile of AMF inoculated seedlings and non-inoculated control seedlings under salinity stress conditions

Arbuscular mycorrhizal fungi (AMF) species are essential in the development of sustainable agriculture, however, their functions in the salinity stress response in legume crops are poorly understood. In this study, peanut (Arachis hypogaea L.) seeds were inoculated with AMF to investigate its alleviation effect on salinity stress. A pot-grown experiment and a field experiment under different soil salinity conditions were carried out. Two genotypes of peanut seeds were inoculated with AMF Rhizophagus irregularis SA and Funneliformis mosseae BEG95 (1: 1). The physiological and transcriptional responses of the AMF-inoculated and non-inoculated peanut plants to salinity stress were investigated. The physiological data revealed that under salinity conditions, the AMF-inoculated plants possessed higher net photosynthetic rate, leaf RWC, plant height, osmolytes accumulation, lower leaf REC, MDA content, and much activated antioxidant system as compared with the non-inoculated plants. The transcriptome data showed that 1,254 and 50 genes were up-regulated in the AMF-inoculated peanut roots compared with the non-inoculated treatment under normal growth conditions and salinity stress, respectively. In the field experiment, inoculation of AMF induced the seed kernels total protein content and significantly increased the pods yield in peanut plants under salinity stress. Taken together, these results strongly argue that the combination of AMF Rhizophagus irregularis SA and Funneliformis mosseae BEG95 (1: 1) could alleviate salinity stress in peanut by improving plant growth, regulating the photosystem, strengthening the antioxidant system, and further increasing the pods yield.