Identification of Salt Stress Response Genes in Rosa chinensis Leaves by Comparative RNA-seq Analysis of Transcriptome Dynamics

Abstract Rosa chinensis Jacq., originating from China, occupied a pivotal position in the floral industry all over the world. Drought and soil salinization is a major problem in the Chinese rose planting industry. Therefore, the study on resistance is important to improve R. chinensis breeding. In this work, leaves of twelve samples with three biological repetitions were collected for transcriptome sequencing. In total 83.14 Gigabyte (G) Illumina sequence data were generated and 74 850 unigenes were successfully annotated. Differentially expressed gene (DEG) analysis was performed by comparing the transcriptomes of the 0, 2, 4 and 7 days salt treatment, based upon which several potential candidate genes involved in salt tolerance response had been identified. DEGs involved in plant hormone signal transduction, photosynthesis, and catalytic activity were examined in depth. The experimental result indicated that the R. chinensis showed strong stress signals after being subjected to salt stress. In the initial stage of salt treatment (two days), plant protective process began to take effect, which was embodied in the regulation of oxidoreductase activities and plant hormone signal transduction pathway. In addition, the expression level of P5CS was up-regulated in R. chinensis, but the proline metabolic pathway was not affected. In the late stage of salt treatment (four and seven days), the photosynthesis – antenna proteins pathway has been greatly affected, and the down-regulated PYL, Snrk2 and MRP lead to the salt tolerance decline, which was consistent with the leaf wilting performance of the R. chinensis in four and seven days of treatment. All the candidate genes were verified by RT-qPCR.