Unravelling Differences in Candidate Genes for Drought Tolerance in Potato (Solanum tuberosum L.) by Use of New Functional Microsatellite Markers.

Christina Schumacher,Heike Sprenger,Manuela Haas,Renate Horn,Rolf Peters,Lisa Maletzki,Christoph Tim Krannich,Karin Köhl,Sylvia Seddig,Dirk Karl Hincha,Sadia Hamera,Joachim Kopka,Ellen Zuther

doi:10.3390/genes12040494

Abstract

Potato is regarded as drought sensitive and most vulnerable to climate changes. Its cultivation in drought prone regions or under conditions of more frequent drought periods, especially in subtropical areas, requires intensive research to improve drought tolerance in order to guarantee high yields under limited water supplies. A candidate gene approach was used to develop functional simple sequence repeat (SSR) markers for association studies in potato with the aim to enhance breeding for drought tolerance. SSR primer combinations, mostly surrounding interrupted complex and compound repeats, were derived from 103 candidate genes for drought tolerance. Validation of the SSRs was performed in an association panel representing 34 mainly starch potato cultivars. Seventy-five out of 154 SSR primer combinations (49%) resulted in polymorphic, highly reproducible banding patterns with polymorphic information content (PIC) values between 0.11 and 0.90. Five SSR markers identified allelic differences between the potato cultivars that showed significant associations with drought sensitivity. In all cases, the group of drought-sensitive cultivars showed predominantly an additional allele, indicating that selection against these alleles by marker-assisted breeding might confer drought tolerance. Further studies of these differences in the candidate genes will elucidate their role for an improved performance of potatoes under water-limited conditions.

Highlights

Drought has become the predominant abiotic stress and major yield limiting factor in crops in the past years [1,2,3]
We present the identification of new functional simple sequence repeat (SSR) markers derived from potential candidate genes for drought tolerance in potato as well as association studies performed with these SSRs in a panel of 34 mainly starch potato cultivars, which were ranked for drought tolerance using DRYM [24] as drought tolerance index
Eighty of the candidate genes were taken from previous publications and 23 were identified in a drought-related transcriptome study as top transcript markers for drought tolerance prediction (Supplementary Table S6, [39])

Summary

Introduction

Drought has become the predominant abiotic stress and major yield limiting factor in crops in the past years [1,2,3]. As a temperate-zone crop with a shallow active root zone, potato is sensitive to drought [18,19] and heavy yield losses are predicted based on climate change prognosis [20,21,22]. Evaluation of marketable tuber yield in a panel of 103 European potato cultivars with different maturity identified cultivars with better performance under non-irrigated conditions and pointed at a single nucleotide polymorphism (SNP) PotVar0030768 from the 14 Infinium SNP marker array to be significantly associated with this trait [26]. Change of plant morphology towards small, open stem-type canopies combined with shallow but dense root systems may be an interesting approach for improving drought tolerance in potato [28]

Methods

Results

Discussion

Conclusion