Transcriptomic Responses of Potato to Drought Stress

Ernest B Aliche,Christian W B Bachem,Richard G F Visser,C Gerard Van Der Linden,Tim Gengler,Irma Hoendervangers,Theo Borm,Marian Oortwijn

doi:10.1007/s11540-021-09527-8

Abstract

AbstractTranscriptomic changes in plants during drought stress give insights into the mechanisms with which plants stabilise their metabolic processes in order to cope with the drought condition. In potato, understanding such drought-induced transcriptomic changes is critical because prolonged field drought interferes with tuber formation and bulking period of potato development, which eventually affects yield. We hypothesised that phenotypic drought responses of potato genotypes may be linked to differences in transcriptomic changes. Using an RNA sequencing approach, we investigated such transcriptomic changes in leaves of three cultivars (Biogold, Hansa and Lady Rosetta) under drought. We found more differentially expressed genes (DEGs) in the tolerant cultivars, Lady Rosetta and Biogold, than in the sensitive cultivar (Hansa). The differential gene expression trend reflected the phenotypic drought responses of the cultivars. For instance, we found in both Biogold and Lady Rosetta but not in Hansa, an upregulation of genes involved in carbohydrate metabolism (e.g., Alpha-glucosidase), flavonoid biosynthesis (e.g., Flavanone 3 beta-hydroxylase), lipid biosynthesis/transfer (e.g., nonspecific Lipid Transfer Proteins), heat shock proteins and secondary metabolites like phenolics and lignins. Furthermore, a prolonged drought stress resulted in reduced DEGs in Biogold and Hansa, but not in Lady Rosetta that also maintained its tuber yield under such prolonged stress suggesting a more robust drought tolerance. Our findings suggest that a synergistic expression of genes involved in several different aspects of drought response is required in order to obtain a robust tolerance.

Highlights

Drought stress is a major problem that reduces agricultural productivity
We found an upregulation of drought-responsive genes like aquaporin gene at 28 days of drought application (28DOD), nonspecific lipid transfer protein at 28DOD, ROS scavenging gene (Glutaredoxin) at 56 days of drought application (56DOD) in both Biogold and Lady Rosetta but not in Hansa (Supplementary File 2)
We propose that the enrichment of sucrose metabolism in Lady Rosetta and Biogold must have significantly aided the maintenance of biomass under stress in contrast to Hansa (Fig. 2a)

Summary

Introduction

Drought stress is a major problem that reduces agricultural productivity. Its effects on plants primarily begin with changes in the expression of genes involved in survival or adaptation to the stress. In order to understand the basis of the drought response mechanisms in potato as well as in other crops, molecular research approaches have been adopted These have resulted in the identification of genes that regulate various aspects of drought response (Vasquez-Robinet et al 2008; Dongjin et al 2011; Xu et al 2014; Obidiegwu et al 2015; Szalonek et al 2015; Gazendam et al 2016). The regulation of these drought-associated genes and their interactions at the molecular level are not yet clearly understood, at least partly because these genes are part of networks and act in concert (Ambrosone et al 2017; Pieczynski et al 2018), and most functional annotations depend on the over-expression or knock-down of single genes. These whole-genomebased molecular investigations have been made even more feasible by advancements in sequencing technology (Heather and Chain 2016)

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