Drought response of tuber genes in processing potatoes (Solanum tuberosum L.) in Japan.

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. Especially the cultivar "Toyoshiro" suitable for processing, has significant reduction in drought yield. Therefore, it is necessary to understand the mechanism of gene expression changes that occur in potato "Toyoshiro" plants and tubers during drought.

Methods and results: Seed potatoes were split in half and one was used as a control plant (CT), and the other was used as a drought-stressed plant (DS). CT was watered daily, and DS watered off to mimic the weather conditions of the Tokachi-Obihiro region in 2021. These tubers were harvested at week 14 and the transcriptome was analyzed. DS plants showed 423 downregulated genes and 197 upregulated genes compared to CT. Factors related to cell wall modification, heat stress response, and phytosterol metabolism were detected among the genes whose expression changed. Moreover, the expression of "Abscisic acid and environmental stress-inducible protein TAS14 like (TAS14)," a molecule reported to be upregulated under drought stress, was also upregulated, and was upregulated expression in all strains that reproduced drought. The localization of this molecule in the nucleus and plasma membrane was confirmed in a mCherry-tagged TAS14 mutant line.

Conclusions: Our findings contribute to understanding the survival strategy system of Japanese processing potatoes in response to drought stress.