Transcriptome modulation by endophyte drives rice seedlings response to Pb stress

This study investigated the growth, SPAD value, chlorophyll fluorescence and transcriptome response of endophyte uninoculated and inoculated rice seedlings under Pb stress after treatment of 1 d and 5 d. Inoculation of endophytes significantly improved the plant height, SPAD value, F_v/F_0, F_v/F_m and PI_ABS by 1.29, 1.73, 0.16, 1.25 and 1.90 times on the 1 d, by 1.07, 2.45, 0.11, 1.59 and 7.90 times on the 5 d, respectively, however, decreased the root length by 1.11 and 1.65 times on the 1 d and 5 d, respectively under Pb stress. Analysis of rice seedlings leaves by RNA-seq, there were 574 down-regulated and 918 up-regulated genes after treatment of 1 d, 205 down-regulated and 127 up-regulated genes after treatment of 5 d, of which 20 genes (11 up-regulated and 9 down-regulated) exhibited the same changing pattern after treatment of 1 d and 5 d. Using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) to annotate these DEGs, and it was found that many of DEGs involved in photosynthesis, oxidative detoxification, hormone synthesis and signal transduction, protein phosphorylation/kinase and transcription factors. These findings provide new insights into the molecular mechanism of interaction between endophyte and plants under heavy metal stress, and contribute to agricultural production in limited environments.