Drought-induced regulatory cascades and their effects on the nutritional
quality of developing potato tubers
Abstract
Potato is among one of the most important food crops, yet maintaining
plant productivity in this drought-sensitive crop has become a
challenge. Competition for scarce water resources and the continued
effects of global warming exacerbate current constraints on crop
production. While plants’ response to drought in above-ground tissues
has been well documented, the regulatory cascades in developing tubers
have been largely unexplored. Using the commercial Canadian cultivar
‘Vigor’, plants were subjected to a drought treatment under high-tunnels
causing a 4 ℃ increase in canopy temperature when compared to the
well-watered control. Tubers were sampled for RNAseq and metabolite
analysis. Approximately 2600 genes and 3898 transcripts were
differentially expressed by at least four-fold in drought-stressed
potato tubers, with 75 % and 69 % being down-regulated respectively. A
further 229 small RNAs were implicated in gene regulation during
drought. The comparison of protein homologues between Solanum tuberosum
L. and Arabidopsis thaliana L. indicates that downregulated genes are
associated with phenylpropanoid, carotenoid and patatin biosynthesis.
This suggests that there are nutritive implications to drought stress
occurring during the potato tuber bulking phase in sensitive cultivars.