Bioforsk-Norwegian Institute for Agricultural and Environmental Research, Kvithamar, 7500 Stjordal, Norway.
Planta. 2013 Jan;237(1):265-77. doi: 10.1007/s00425-012-1771-2. Epub 2012 Sep 27.
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.
利用人工冷冻试验，鉴定与低温耐受过程相关或直接参与的生物标志物，可能对应用草莓育种有用。本研究旨在鉴定不同低温耐受能力的二倍体草莓基因型，并研究一组候选蛋白和代谢物是否与耐受水平相关。评估了 17 个野生草莓（Fragaria vesca）、2 个森林草莓（F. nilgerrensis）、2 个东方草莓（F. nubicola）和 1 个五叶草莓（F. pentaphylla）基因型对低温的耐受性。估计 50%植物存活的温度（LT₅₀）在基因型间的范围为-4.7 至-12.0°C。在野生草莓中，LT₅₀范围为-7.7 至-12.0°C。最耐寒的是三个野生草莓亚种 bracteata 基因型（FDP821、NCGR424 和 NCGR502），而一个野生草莓亚种 californica 基因型（FDP817）则最不耐寒（LT₅₀）为-7.7°C）。在 2°C 下驯化选择植物，测定醇脱氢酶（ADH）、总脱水素表达和中心代谢物含量。LT₅₀估计值与 ADH 和总脱水素的表达高度相关（r（adh）=-0.87，r（dehyd）=-0.82）。在驯化过程中，测定叶片中柠檬酸循环相关化合物的含量。虽然在驯化早期，几种糖和酸与 LT₅₀估计值显著相关，但只有半乳糖醇在驯化 28 天后被证明是 LT₅₀的良好预测因子（r（半乳糖）=0.79）。综上所述，ADH、脱水素和半乳糖醇在二倍体草莓中作为低温耐受生物标志物具有很大的潜力。
