Transcriptome profile of drought responsive candidate genes in varieties of citrus rootstocks with different tolerance strategies

Abstract Sunki Maravilha' and 'Sunki Tropical' are citrus plants with different drought tolerance strategies. `Sunki Tropical' is considered as another rootstock alternative for use in drought prone areas, however, its genetic expression profiles regarding response to water deficit, are still unknown. In this study, the transcriptome of the ‘Sunki Maravilha’ and ‘Sunki Tropical’ rootstocks under control were analyzed by RNA-seq technique using the Illumina HiSeq-2500. A total of 109,114.164 reads were produced and mapped against the Citrus sinensis reference genome (version 1.1). 3.607 transcripts showed significant variation in expression between the water deficit and control treatments with 739 genes up-regulated and 2868 down-regulated during water deficit imposition. The differentially expressed genes (DEGs) identified are involved in more than 100 biological processes and molecular functions whereas most enriched for the function of oxidoreductase, protein phosporilation, transcriptional regulation, ligation processes and response to oxidative stress. DEGs related to the biosynthesis of ABA (Abscisic Acid), redox system, cell wall mechanism, root development, transcription factors (TFs) and kinase proteins (KPs), were also identified. This work lays the basic foundation for further investigation of the specific functions of genes in citrus rootstocks, Sunki Maravilha’ and Sunki Tropical’, with different strategies of survival under water deficit and also provides candidate genes for engineering or breeding of citrus plants aiming drought tolerance.