Transcriptomes and metabolic regulation of potatoes  in response to drought stress
Background: Limited crop production due to lower rainfall has a major impact on the supply and demand of food for the human population. In potato (Solanum tuberosum L. ), one of the major crops, there is also concern about a lack of production due to drought stress. Therefore, it is necessary to understand the mechanism of gene expression changes that occur in potato tubers during drought.Results: Potatoes under drought stress with water supply limitation were cultivated, and tubers were harvested at week 14. Total RNA was extracted from tubers, and the transcriptome was analyzed. The stressed plants showed 423 downregulated genes and 197 upregulated genes compared to the control. Factors related to phytosterol metabolism, cell wall modification, and heat stress response were detected among the genes whose expression changed. Analysis of leaf components of each strain revealed that the level of cycloartenol, a starting material for alkaloids and steroids, was 0.63-fold lower in the stressed strain. This result correlated with the transcriptome and qPCR analysis data. Moreover, the expression of "Abscisic acid and environmental stress-inducible protein TAS14 like (TAS14)," a molecule reported to be upregulated in several cultivars under drought stress, was also upregulated, and the localization of this molecule in the nucleus and plasma membrane was confirmed in an mCherry-tagged TAS14 mutant line.Conclusion: These results contribute to understanding the survival strategy system of potatoes in response to drought stress.Keywords: Potato, Drought stress, Transcriptome, Phytosterol, TAS14