Genomewide identification of genes involved in the potato response to drought indicates functional evolutionary conservation with Arabidopsis plants

Abstract

SummaryPotato is one of the four most important food crop plants worldwide and is strongly affected by drought. The following two pairs of potato cultivars, which are related in ancestry but show different drought tolerances, were chosen for comparative gene expression studies: Gwiazda/Oberon and Tajfun/Owacja. Comparative RNA‐seq analyses of gene expression differences in the transcriptomes obtained from drought‐tolerant versus drought‐sensitive plants during water shortage conditions were performed. The 23 top‐ranking genes were selected, 22 of which are described here as novel potato drought‐responsive genes. Moreover, all but one of the potato genes selected have homologues in the Arabidopsis genome. Of the seven tested A. thaliana mutants with altered expression of the selected homologous genes, compared to the wild‐type Arabidopsis plants, six showed an improved tolerance to drought. These genes encode carbohydrate transporter, mitogen‐activated protein kinase kinase kinase 15 (MAPKKK15), serine carboxypeptidase‐like 19 protein (SCPL19), armadillo/beta‐catenin‐like repeat‐containing protein, high‐affinity nitrate transporter 2.7 and nonspecific lipid transfer protein type 2 (nsLPT). The evolutionary conservation of the functions of the selected genes in the plant response to drought confirms the importance of these identified potato genes in the ability of plants to cope with water shortage conditions. Knowledge regarding these gene functions can be used to generate potato cultivars that are resistant to unfavourable conditions. The approach used in this work and the obtained results allowed for the identification of new players in the plant response to drought.

Divergent strategies displayed by potato (Solanum tuberosum L.) cultivars to cope with soil drought

“…Considering the number of different mechanisms by which perturbations in water availability may affect potato yield in agronomic terms, in our study, we focused on the impacts of “meteorological droughts” (Wilhite & Glantz, ), which represent periods of precipitation deficiency, high temperatures and low humidity. To enhance our understanding of the physiology and genetics of resistance, drought resistance of potato cultivars was estimated on the basis of potato physiological responses to soil drought presented here as well as on the basis of comparative gene expression studies presented elsewhere (Pieczynski et al., ). Qualitative and quantitative global analyses of gene expression, carried out parallel to the physiological experiments on the same pairs of potato cultivars, gain more insight into genetic background of drought tolerance.…”

“…The evolutionary conservation of the functions of the selected genes in the plant response to drought confirms their importance in the ability of potato plants to cope with water deficiency. Knowledge regarding functions of these genes seems to facilitate the genetic improvement of potato cultivar tolerance to unfavourable conditions (Pieczynski et al., ).…”

“…The drought tolerance of the cultivars was assessed visually using wilting and regeneration scales (Boguszewska, Grudkowska, & Zagdańska, ; see also Fig. S2 in Pieczynski et al., ). The wilting process was assessed visually using a nine‐point wilting scale, where 9 means lack of wilting, 7 means that only lower leaves are wilted, 5 means that less than half of the plant is wilted, 3 means that only the top of the plant is not wilted, 2.5 means that the whole plant with the top is wilted, 2 means that whole plant is wilted and lower leaves are dry, 1.5 means that dry leaves are present in higher parts of the plant, 1 means that leaves are green only in the top part of the plant, and 0.5 means that only stems are green.…”

“…The evolutionary conservation of the functions of the selected genes in the plant response to drought confirms their importance in the ability of potato plants to cope with water deficiency. Knowledge regarding functions of these genes seems to facilitate the genetic improvement of potato cultivar tolerance to unfavourable conditions(Pieczynski et al, 2017).From an agronomical point of view, maintaining yield levels during drought is crucial for breeders, and thus, the drought tolerance of cultivars has been quantified from tuber yield under irrigated and soil drought conditions. However, this manner of evaluating of plant drought resistance depends, among other things, on the adaptation of the plant's developmental cycle to periodically occurring drought, on changes in the anatomical-morphological structure of aboveground organs which protect tissue against water loss, and also on dehydration tolerance.…”

Transcriptome Response to Drought, Rehydration and Re-Dehydration in Potato

“…Transcriptome analysis showed that transcription factors, protein kinases, proteins related to redox regulation, carbohydrate metabolism and osmotic adjustment participate in the tolerance of potato to osmotic stress [8][9][10]. Twenty-three drought-responsive genes were identified by comparing the transcriptomes of drought-tolerant and drought-sensitive potato varieties under water stress, and seven homologous genes were identified by homozygous mutants of Arabidopsis thaliana, six of them including carbohydrate transporter, 2 of 17 mitogen-activated protein kinase kinase kinase 15 (MAPKKK15), serine-like carboxypeptidase 19 (SCPL19), armadillo/beta-catenin-like repeat-containing protein, high-affinity nitrate transporter 2.7 and nonspecific lipid transfer protein 2 (nsLPT) can improve the drought resistance of Arabidopsis [11]. These results suggest the complexity of the molecular mechanism of potato drought-resistance.…”