Drought-Induced Regulatory Cascades and Their Effects on the Nutritional Quality of Developing Potato Tubers.

Letitia Da Ros,Benoit Bizimungu,Shankar Pahari,Raju Soolanayakanahally,Manoj Kulkarni,Jazeem Wahab,Raed Elferjani,Sateesh Kagale

doi:10.3390/genes11080864

Abstract

Competition for scarce water resources and the continued effects of global warming exacerbate current constraints on potato crop production. While plants’ response to drought in above-ground tissues has been well documented, the regulatory cascades and subsequent nutritive changes in developing tubers have been largely unexplored. Using the commercial Canadian cultivar “Vigor”, plants were subjected to a gradual drought treatment under high tunnels causing a 4 °C increase in the canopy temperature. Tubers were sampled for RNAseq and metabolite analysis. Approximately 2600 genes and 3898 transcripts were differentially expressed by at least 4-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. Expression of several small RNA clusters negatively correlated with expression of their six target patatin genes, suggesting involvement in the regulation of storage proteins during drought. The comparison of protein homologues between Solanum tuberosum L. and Arabidopsis thaliana L. indicated that down-regulated genes were associated with phenylpropanoid and carotenoid biosynthesis. As is indicative of reduced flow through the phenylpropanoid pathway, phenylalanine accumulated in drought-stressed tubers. This suggests that there may be nutritive implications to drought stress occurring during the potato tuber bulking phase in sensitive cultivars.

Highlights

Potatoes are the fourth most consumed food crop worldwide and are an efficient source of energy, vitamins and minerals in the human diet [1]
High consumption rates and moderate concentrations of dietary antioxidants have led potatoes to be the third-largest source of total phenolics in the American diet [2]
Prominent characteristics of the cultivar are were grown under optimum soil moisture conditions at 70% field capacity (FC) and restricted soil its yellow-fleshed tubers and pigmented flowers

Summary

Introduction

Potatoes are the fourth most consumed food crop worldwide and are an efficient source of energy, vitamins and minerals in the human diet [1]. High consumption rates and moderate concentrations of dietary antioxidants have led potatoes to be the third-largest source of total phenolics in the American diet [2]. Diets rich in phenolics have been implicated in the prevention of an array of degenerative diseases and concentrations of these compounds vary greatly based on the cultivar, highlighting the potential for the targeted breeding of potato (S. tuberosum L.) to enhance global human health [3]. The production and accumulation of these compounds are favored at lower temperatures, with potatoes grown in warm, dry regions producing lower amounts of phenolics [4]. Environmental parameters could be manipulated to manage the concentrations of desired phytonutrients [4,5,6]

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