RNA-sequencing predicts three novel genes in response to drought in electron beam irradiation treated tobacco

Abstract

Electron beam irradiation (EBI) has protective effects on food storage. This study aimed to investigate drought tolerance of tobacco after EBI treatment. Nicotiana tabacum L. seeds were irradiated with different doses of EBI. Germination percentage (GP) was counted. Phenotype of EBI-treated M1 generation was observed in a drought field. The candidate drought-resistant tobacco line was selected and then drought treated without watering for 8 and 16 days, respectively. Samples at 8 days were collected for RNA-sequencing on the Illumina HiSeqTM 2500 platform. Then, differentially expressed genes (DEGs) were selected, followed by functional enrichment analysis. EBI with 500 Gy was selected as the optimal dose. Five lines: M1-7, M1-9, M1-10, M1-12, and M1-40 were candidate drought-resistant lines based on phenotype observation. Among them, M2-12 and M2-40 had high GPs. By comparing their M1 phenotypes, M2-12 was identified as the final candidate drought-resistant line. After drought treatment, M2-12 showed a wavier leaf margin than control and kept a well growth condition during the whole period. A total of 3547 DEGs were identified, and the up-regulated DEGs were significantly enriched in functions like “response to water deprivation (LOC107782385)”, “response to gibberellin (LOC104231633, LOC104219851)”, and “response to jasmonic acid (JA) (LOC104219851)”. Results of qRT-PCR confirmed that LOC104231633, LOC107782385, and LOC104219851 were up-regulated under drought stress. In conclusion, EBI may be a promising way to generate drought tolerant mutant tobacco. The above three genes may be drought-inducible and may involve in JA- and gibberellin-mediated signaling pathways.