Integrated transcriptome and metabolome revealed the drought responsive metabolic pathways in Oriental Lily (Lilium L.).

Abstract

Lily is an essential ornamental flowering species worldwide. Drought stress is a major constraint affecting the morphology and physiology and lily leaves and flowers. Therefore, understanding the molecular mechanism underlying lily response to drought stress is important. Transcriptome and metabolome analysis were performed on Oriental Lily subjected to drought stress. Most transcription factors and metabolites yielded by the conjoint analysis displayed a downregulated expression pattern. Differential genes and metabolites mainly co-enriched in glycolic pathways related to sugars, such as galactose, and sucrose, glycolysis and gluconeogenesis, indicating that drought stress reduced the sugar metabolism level of Oriental Lily. Combined with transcriptome and metabolome data, nine pairs of differentially expressed metabolites and the genes (p < 0.05) were obtained. Interestingly, a gene named TRINITY_DN2608 (encoding a type of alpha-D-glucose) cloned and its overexpression lines in Arabidopsis thaliana was generated. Overexpression of TRINITY_DN2608 gene elevated the susceptibility to drought stress possibly by suppressing the glucose level. The enrichment of sugar-related pathways advocates the potential role of glucose metabolism in drought stress. Our study provides theoretical information related to the glucose-mediated drought response and would be fruitful in future lily breeding programs.