Identification and Expression Pattern Analysis of AsSWEET Gene Family in Achnatherum splendens

Sugars Will Eventually Be Exported Transporters (SWEETs) are involved in plant growth and development, particularly in resistance to adverse environments. Achnatherum splendens (Trin.) Nevski exhibits rhizosheath formation and demonstrates notable salt and drought tolerance. We identified 31 sugar transporter family genes (AsSWEETs) from the Achnatherum splendens genome in the NCBI database and performed bioinformatics analyses, including gene structure, subcellular localization, conserved sequences, promoter cis-acting elements, phylogenetic relationships, and chromosomal localization. The 31 AsSWEET genes are distributed across 13 chromosomes, encoding peptides ranging from 375 to 1353 amino acids. Their predicted molecular weights range from 31,499.38 to 109,286.91 Da, with isoelectric points (pI) between 4.78 and 5.21. The aliphatic index values range from 13.59 to 24.19, and the grand average of hydropathicity (GRAVY) values range from 0.663 to 1.664. An analysis of promoter cis-acting elements reveals that all 31 AsSWEET genes contain multiple elements related to light, stress, and hormone responses. Subcellular localization predictions indicate that most genes in this family are localized to the plasma membrane or tonoplast, with AsSWEET12-2 and AsSWEET3b localized in chloroplasts and AsSWEET2b-2 in the nucleus. qRT-PCR results show that AsSWEET13-1, AsSWEET13-3, and AsSWEET1a exhibit upregulated expression in response to salt and drought stress in the roots of Achnatherum splendens. These genes may serve as candidate genes for investigating the stress resistance mechanisms of Achnatherum splendens. The findings provide a theoretical basis for further research on stress resistance mechanisms and candidate gene identification under salt and drought stress in Achnatherum splendens.