Transcriptome Analysis of the Molecular Mechanisms of High Salinity Resistance in Spartina alternifolia

Spartina alterniflora is the most widely distributed invasive vegetation in coastal wetlands in China. Its strong invasion and diffusion ability is inseparable from its high salinity resistance. In order to clarify its response to salinity stress and resistance mechanism, this study carried out a series of experiments on S. alterniflora with 3-5 seedings treated at 10, 24, and 32 salinity conditions, and transcriptome sequencing analysis was performed using Illumina high-throughput sequencing technology. A total of 121 760 unigenes and 1 190 differentially expressed genes (DEGs) were obtained Genes highly related to salt tolerance of S. alterniflora, such as proline metabolism related genes (Sporobolus alterniflorus delta 1-pyrroline-5-carboxylate synthetase 2, SaP5CS2), cation transporters with stable Na⁺/K⁺ ratio (cation transporter HKT7), sodium/hydrogen exchangers 2(NHX2), and resistance to k⁺ efflux 5, were mined. Go functional annotation results showed that DEGs were mainly related to catalytic activity, transport activity, cellular processes, metabolic processes and cellular components, etc. KEGG enrichment results showed that DEGs were mainly enriched in pathways such as cyanoamino acid metabolism pathway, oxidative phosphorylation metabolism pathway and photosynthesis antenna protein pathway, etc. Function gene interaction network analysis showed that the significantly enriched phenylpropanoid metabolism pathway, oxidative phosphorylation pathway (LG vs CG Group), nitrogen metabolism, photosynthesis antenna protein, ECM receptor interaction, P13K-Akt signaling pathway, oxidative phosphorylation and other pathways (Hg vs CG Group), cyanoamino acide metabolism, glucosinolate biosynthesis, brassinosteroid biosynthesis, cutin pathways such as cork and wax biosynthesis (HG vs LG Group) were all related to the stress resistance of S. alterniflora. Therefore, this study provides basic information on the molecular mechanism of biological invasion and proliferation by mining the salt resistance key genes and metabolic pathways of S. alterniflora, and provides important references for the direction of prevention and control technology for invasive species such as S. alterniflora, and has important economic and ecological significance.