Transcriptome dynamics of the Camellia sinensis in response to continuous salinity stress and drought stress

Background:Camellia sinensisis one of most popular non-alcoholic beverages and a important economic crops worldwide. Salinity, together with drought pose a serious threaten to economic crops, such as C.sinensis.Changes that occur at the molecular level in response to drought stress and salt stress are poorly understood in tea plants. To know the molecular mechanisms of C.sinensis response to drought stress and salt stress, we employed RNA-Seq technologies to the study of genome-wide expression profiles during drought stress and salt stress in tea plants. Results: Using high-throughput Illumina sequencing platform, approximately 398.95 million high-quality paired-end reads generated from young leaves with drought stress and salt stress in continuous time points were abtained for De novo assembly. The transcripts with further processing and filtering yielded a set of 64,905 CDSs with an average length of 710 bp and an N50 of 933 bp. In total, 3,936 DEGs were identified from all time pionts of drought stress and 3,715 DEGs were identified from all time points of salt stress. In addition, we clustered the 3,936 DEGs and 3,715 DEGs by their expression dynamics into four clusters repectively, and the genes in each cluster showed enrichment for particular functional categories. We also found that most of DEGs show a down-regulation in all time points and activated after 48 h in salt stress, while most of DEGs only show a down-regulation in all time points with drought stress. Conclusion:We reported the first large-coverage tanscriptome datasets for C.sinensis with drought stress and salt stress using next-generation sequencing technology. All findings suggest that gene expression rapidly and coordinately changes during C.sinensis adaptation to drought stress and salt stress, and show some common characteristic in C.sinensis response to both stress. In addition, the identified DEGs provide an critical genetic resources for further functional analyses and probabilityof potential transgenic modifications for developing salt-tolerant and drought-tolerant tea plants