Comparative transcriptomics reveals key genes contributing to the differences in drought tolerance among three cultivars of foxtail millet (Setaria italica)

Abstract

Foxtail millet (Setaria italica L.) is an important food crop with strong drought stress tolerance. The response of foxtail millet to drought stress is a complex regulatory network. It is of great guiding significance for agricultural production to continuously explore candidate genes of foxtail millet drought resistance and reveal the molecular regulatory mechanism and metabolic pathway of foxtail millet drought tolerance. This study investigated three different cultivars of foxtail millet with different drought resistance. Drought stress reduced the water and chlorophyll content, and increased the Malondialdehyde (MDA) level and soluble protein of foxtail millet leaves. From strong to weak, the drought resistance order was Jigu39, Jingu21, and Longgu16. The transcriptome analysis of these three cultivars was carried out. 2954, 1531, and 2344 deferentially expressed genes under drought stress were identified in Jigu39, Jingu21, and Longgu16. The GO and KEGG pathway analysis identified DEGs significantly enriched in photosynthesis, chlorophyll metabolism, amino acid metabolism, and carbohydrate metabolism in all three cultivars. In addition, we identified 46 genes whose trends of transcription change were consistent with the drought resistance trends among three cultivars of foxtail millet. Among them, 32 genes were first identified related to drought response in foxtail millet, which was worth further research.