Protein expression changes in response to potassium deficiency stress of industrial hemp plants using SWATH technology

Potassium availability in soil is one of the most important factors affecting the growth and metabolism of industrial hemp, having a major influence on plant growth and crop yield. SWATH proteomics was used to perform differential proteomics on rapidly-growing stems and leaves of a potassium-deficiency resistant (BM) and a potassium deficiency sensitive hemp variety (Y1), under potassium deficiency stress (0.2 mmol/L K+ in irrigation water). The differentially expressed proteins (DEPs) in BM and Y1 were identified through LC-ESI-MS/MS, finding 288 and 353 stem DEPs and 226 and 256 leaf DEPs, respectively. KEGG pathway analysis of the two varieties revealed that the DEPs in Y1 leaf, BM leaf, Y1 stem and BM stem were significantly enriched in 15, three, 11 and four pathways, respectively. Comparison and analysis of the DEPs, revealed that BM adapted to potassium deficiency stress through the following mechanisms: chlorophyll synthesis in both stem and leaf decreased and photosynthesis slowed; stem increased starch metabolism, oxidative stress resistance, lignin metabolism, cell membrane biosynthesis, cell division and ethylene biosynthesis; leaf regulated stomatal closure, enhanced photo-respiration and light energy transfer and activated protein anabolism. These findings provide important reference proteins and genetic information for future molecular study of the highly-efficient absorption of potassium by industrial hemp plants.