Chrysanthemum × Grandiflora Leaf and Root Transcript Profiling in Response to Salinity Stress

As high soil salinity threatens the growth and development of plants, understanding the mechanism of plants’ salt tolerance is critical. As a newly developed species with a strong salt resistance, the chrysanthemum × grandiflora possesses multiple genes that control its quantitative salt resistance. Because of this multigene control, we chose to investigate the plant’s stress genes’ overall responses at the transcriptome level. C. Grandiflora were treated with a 200 mM/L NaCl solution for 12 h, and the effect of salt stress on their roots and leaves was analyzed via Illumina RNA sequencing. Most DEGs were enriched in GO annotations of ‘biological process,’ ‘nucleus,’ and ‘protein binding’. There are many genes in plant hormone signal transduction and phenylpropane biology pathways, and we observed that most of the genes had the same expression patterns in the roots and leaves. Among them, PAL , CYP73A , and 4CL in the phenylpropane biosynthetic pathway were upregulated in roots and leaves. In the salicylic acid signal transduction pathway, TGA7 was upregulated in the roots and leaves, and in the jasmonic acid signal transduction pathway, TIFY9 was upregulated in the roots and leaves. In the ion transporter gene, we identified that HKT1 showed identical expression patterns in the roots and leaves. In order to verify the accuracy of the Illumina sequencing data, we selected 16 DEGs for transcription polymerase chain reaction (qRT-PCR) analysis. qRT-PCR and transcriptome sequencing analysis revealed that the transcriptome sequencing results were reliable.