Increasing drought conditions in Mediterranean countries are negatively impacting the survival and productiv-ity ofCastanea sativaMill. The study aimed to select EST-SSR markers associated with drought stressdeveloped inQuercusspp. and evaluate their transferability and polymorphism inC. sativa. Eight EST-SSR mar-kers were selected to examine the adaptive potential of four wild populations ofC. sativain relation todrought tolerance. To validate markers, offspring of the study trees were water stressed and their drought tol-erance was assessed. EST-SSR markers and leaf wilting of seedlings after drought treatment revealed anorth-south gradient ofC. sativapopulations. The heritability value obtained for the'leaf wilting'trait (h2=0.26±0.08) indicated that selection for drought tolerance is possible. The differentiation coefficient of mar-kers showing neutral selection (FST=0.080) was lower than the quantitative genetic differentiation of popula-tions (QST=0.28), indicating that selection of drought tolerant trees acted spatially in a heterogeneousmanner. When assessing the genetic structure of populations,FIR080was identified as outlier locus underpositive selection. When assessing the phenotypic tolerance to drought of offspring,GOT004andGOT045wereidentified as outlier loci under balancing selection andFIR059was identified as an outlier locus under positiveselection.FIR059showed three private alleles for drought-susceptible individuals and two private alleles fordrought-tolerant individuals and could therefore be considered as a candidate marker to predict drought tol-erance in unstressedC. sativatrees. Combined use of functional markers and phenotypic traits is a powerfulapproach to determine genetic variation at the adaptive level inC. sativa. The results illustrate the potential ofEST-SSR markers for early selection of drought tolerant plant material
Adaptive diversity and drought tolerance in Castanea sativa assessed through genic markers EST-SSR
Claudia Mattioni;
2019
Abstract
Increasing drought conditions in Mediterranean countries are negatively impacting the survival and productiv-ity ofCastanea sativaMill. The study aimed to select EST-SSR markers associated with drought stressdeveloped inQuercusspp. and evaluate their transferability and polymorphism inC. sativa. Eight EST-SSR mar-kers were selected to examine the adaptive potential of four wild populations ofC. sativain relation todrought tolerance. To validate markers, offspring of the study trees were water stressed and their drought tol-erance was assessed. EST-SSR markers and leaf wilting of seedlings after drought treatment revealed anorth-south gradient ofC. sativapopulations. The heritability value obtained for the'leaf wilting'trait (h2=0.26±0.08) indicated that selection for drought tolerance is possible. The differentiation coefficient of mar-kers showing neutral selection (FST=0.080) was lower than the quantitative genetic differentiation of popula-tions (QST=0.28), indicating that selection of drought tolerant trees acted spatially in a heterogeneousmanner. When assessing the genetic structure of populations,FIR080was identified as outlier locus underpositive selection. When assessing the phenotypic tolerance to drought of offspring,GOT004andGOT045wereidentified as outlier loci under balancing selection andFIR059was identified as an outlier locus under positiveselection.FIR059showed three private alleles for drought-susceptible individuals and two private alleles fordrought-tolerant individuals and could therefore be considered as a candidate marker to predict drought tol-erance in unstressedC. sativatrees. Combined use of functional markers and phenotypic traits is a powerfulapproach to determine genetic variation at the adaptive level inC. sativa. The results illustrate the potential ofEST-SSR markers for early selection of drought tolerant plant materialI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
