Dehydrin, alcohol dehydrogenase, and central metabolite levels are associated with cold tolerance in diploid strawberry (Fragaria spp.)

Abstract

The use of artificial freezing tests, identification of biomarkers linked to or directly involved in the low-temperature tolerance processes, could prove useful in applied strawberry breeding. This study was conducted to identify genotypes of diploid strawberry that differ in their tolerance to low-temperature stress and to investigate whether a set of candidate proteins and metabolites correlate with the level of tolerance. 17 Fragaria vesca, 2 F. nilgerrensis, 2 F. nubicola, and 1 F. pentaphylla genotypes were evaluated for low-temperature tolerance. Estimates of temperatures where 50 % of the plants survived (LT₅₀) ranged from -4.7 to -12.0 °C between the genotypes. Among the F. vesca genotypes, the LT₅₀ varied from -7.7 °C to -12.0 °C. Among the most tolerant were three F. vesca ssp. bracteata genotypes (FDP821, NCGR424, and NCGR502), while a F. vesca ssp. californica genotype (FDP817) was the least tolerant (LT₅₀) -7.7 °C). Alcohol dehydrogenase (ADH), total dehydrin expression, and content of central metabolism constituents were assayed in select plants acclimated at 2 °C. The LT₅₀ estimates and the expression of ADH and total dehydrins were highly correlated (r(adh) = -0.87, r (dehyd) = -0.82). Compounds related to the citric acid cycle were quantified in the leaves during acclimation. While several sugars and acids were significantly correlated to the LT₅₀ estimates early in the acclimation period, only galactinol proved to be a good LT₅₀ predictor after 28 days of acclimation (r(galact) = 0.79). It is concluded that ADH, dehydrins, and galactinol show great potential to serve as biomarkers for cold tolerance in diploid strawberry.

Cold acclimation efficiency of different Prunus and Fragaria species and cultivars in vitro

“…Changes in the expression of hundreds of genes, total reconfiguration of metabolite profiles and accumulation of specific compounds during cold acclimation have been demonstrated in different plants (Kaplan et al, 2007;Rohloff et al, 2012). It was revealed that alcohol dehydrogenase, dehydrins, and galactinol show great potential to serve as biomarkers for cold tolerance of different Rosacea plants (Baniulis et al, 2012;Koehler et al, 2012;Davik et al, 2013). The data of our study corresponded well with the results obtained by other researchers.…”

“…Three weeks of cold hardening using alternating temperature can be recommended as a standard protocol for Malus germplasm cryopreservation (Kushnarenko et al, 2009). Before freezing studies, diploid strawberry plants were acclimated for 6 weeks at 2°C and 10-h photoperiod in vitro (Davik et al, 2013). A study of influence of cold hardening on strawberries showed that 9 weeks of cold hardening provided the best results, while longer chilling treatment of plantlets resulted in weak growth (Borkowska, Michalczuk, 2000).…”

“…The survival of fruit plants during winter is affected by several factors or physiological responses, e.g., 1) growth cessation, 2) effective cold hardening in autumn, 3) sufficient minimal temperatures in January to complete the endodormancy phase and 4) the response to growth stimuli in periods of temporarily increased temperatures. With a range of biotic and abiotic factors contributing and interacting, disentangling the full story of winter survival has proven difficult (Davik et al, 2013). However, low temperature stress per se is one of the most important aspects of winter survival.…”

“…Measuring electrolyte leakage is one of the most frequently used methods to assess plant tolerance in response to drought and low temperature (Davik et al, 2013). Abiotic stresses induce cell membrane injury, leading to the efflux of intracellular ions.…”

Ornamental potential and freezing tolerance of six Thymus spp. species as ground-covering plants in the landscape

“…The degree of cell membrane injury induced by an abiotic stress is easily estimated by measuring the cells' electrolyte leakage. Measurement of electrolyte leakage is one of the most frequently used methods to assess plant tolerance in response to drought and low temperature (Davik et al, 2013). Nunes and Ray Smith (2003) reported that the electrolyte leakage (EL) test performed on young leaves at −14°C temperature for 60 min proved to be the most efficient means for detecting both acclimation and cultivar differences in rose clover freezing tolerance.…”