Climatic adaptation in Picea abies progenies is affected by the temperature during zygotic embryogenesis and seed maturation

Abstract

The temperature during maternal reproduction affects adaptive traits in progenies of Norway spruce ( Picea abies (L) Karst.). Seed production in a cold environment advances bud set and cold acclimation in the autumn and dehardening and flushing in spring, whereas a warm reproductive environment delays timing of these traits. We repeated crosses between the same parents and produced seeds under contrasting temperatures. Elevated temperatures were applied at different time points from female meiosis to embryogenesis, followed by full-sib progeny tests in common environments. We measured timing of terminal bud formation, cold acclimation in the autumn and transcription levels of conifer phytochromes PhyO, PhyN , PhyP , and the class IV chitinase PaChi4 in these tests. No progeny differences were found that could be related to temperature differences during prezygotic stages and fertilization. In contrast, progeny performance was strongly associated with the degree-days from proembryo to mature seeds. Progenies with a warm embryonic history formed terminal buds later, were less hardy and expressed lower transcription levels of the Phy and PaChi4 genes. We hypothesize that temperature during zygotic embryogenesis and seed maturation regulates an 'epigenetic memory' in the progeny, involving differential expression of genes that may regulate bud phenology, cold acclimation and embryogenesis in Norway spruce.

Variation de la résistance au gel au printemps et en automne entre et dans les populations espagnoles sauvages de Castanea sativa

“…Prior to the analyses, all traits were transformed per block by the use of a normal score transformation, as they were all categorical traits with an underlying increase in severity of the injury or advance in development from one class to the next (Johnsen et al, 2005). The transformations restored normality and homogeneity of variances to the distributions.…”

Divergence among species and populations of Mediterranean pines in biomass allocation of seedlings grown under two watering regimes

“…This question has been the focus of interest in science in general and in forest science in particular during the last two hundred years [23]. In most cases, those phenotypic changes due to genotype by environment interactions were considered as a source of error in most breeding and genetic evaluation programs, and several techniques have been developed to deal with this topic [20,38,47]. However, recently new perspectives were open to the analyses of those changes, when seen from a more general point of view, and taking into consideration different evolutionary implications.…”

Epigenetic memory effects in forest trees: a victory of “Michurinian biology”?

“…Cold environment advanced autumn bud set, cold acclimation, spring dehardening and flushing. On the other hand, the conditions during the pre-zygotic stage and fertilization did not affect phenology (Johnsen et al 2005a). The effect of temperature also interacts with the daylength effects, plants subjected to high temperature and long days and those subjected to low temperature and short days expressed characteristics similar to cold-subjected individuals from the genetics.…”

“…Johnsen et al (2005a) mentioned unpublished data suggesting that plants from warmer environment had higher levels of the overall DNA cytosine methylation. Yakovlev et al (2010) found and sequenced 16 micro-RNAs that showed different transcription levels between cold-environment and warm-environment Norway spruce individuals.…”