A candidate gene association analysis identifies SNPs potentially involved in drought tolerance in European beech (Fagus sylvatica L.)

Abstract

Studies of genetic variation underlying traits related to drought tolerance in forest trees are of great importance for understanding their adaptive potential under a climate change scenario. In this study, using a candidate gene approach, associations between SNPs and drought related traits were assessed in saplings of European beech (Fagus sylvatica L.) representing trees growing along steep precipitation gradients. The saplings were subjected to experimentally controlled drought treatments. Response of the saplings was assessed by the evaluation of stem diameter growth (SDG) and the chlorophyll fluorescence parameters FV/FM, PIabs, and PItot. The evaluation showed that saplings from xeric sites were less affected by the drought treatment. Five SNPs (7.14%) in three candidate genes were significantly associated with the evaluated traits; saplings with particular genotypes at these SNPs showed better performance under the drought treatment. The SNPs were located in the cytosolic class I small heat-shock protein, CTR/DRE binding transcription factor, and isocitrate dehydrogenase genes and explained 5.8–13.4% of the phenotypic variance. These findings provide insight into the genetic basis of traits related to drought tolerance in European beech and could support the development of forest conservation management strategies under future climatic conditions.

High plasticity in germination and establishment success in the dominant forest tree Fagus sylvatica across Europe

“…Plasticity in fitness traits may moderate and exceed the role of static local adaptation in adaptive processes during climate change in the centre of species distribution ranges, in particular for long‐living trees (Benito Garzón et al., 2019; Stojnić et al., 2018). However, the interaction of evolutionary local adaptation and plasticity under extreme weather events still remains unclear (Cuervo‐Alarcon et al., 2021) and should be subject of future research, in particular at species distribution margins with high selection pressure and strong evolutionary dynamics (Hampe & Petit, 2005).…”

“…However, the reported lower genetic diversity towards the north is valid at population level, whereas the genetic variation within populations may remain quite high across the whole range of the species (Vornam et al., 2004). Adaptive traits and performance of beech under drought are genetically determined (Cuervo‐Alarcon et al., 2021), arise from both local genetic adaptation and phenotypic plasticity (Bolte et al., 2016; Stojnić et al., 2018), and are also moderated by other ecological factors like light availability (Wang et al., 2021). To better understand the population dynamics of this species across its whole distribution range, it is therefore crucial to consider the increasing likelihood of drought events in large parts of the distribution of beech with climate change (Kovats et al, 2014) and its projected distribution range shift towards the north (Kramer et al., 2010; Saltre et al., 2015).…”

Oaks as Beacons of Hope for Threatened Mixed Forests in Central Europe

“…Under future climate projection, 10-16% growth rate decline is predicted for F. sylvatica by 2100, while an increase of 12% growth rate is expected for Q. robur (Huang et al, 2017). Therefore, in climatically warmer areas, where beech is likely to reach its limits (Kramer et al, 2010), oak may prevail over beech because it is already adapted to the warmer climate (Delb, 2012;Cuervo-Alarcon et al, 2021). In more northern regions, on the other hand, a successful strategy should be to support oak and beech to maintain resilient mixed forests that help mitigate the effects of climate change because an adequate species mix can even lead to increased productivity (Pretzsch et al, 2013).…”

Genomic signatures of natural selection at phenology-related genes in a widely distributed tree species Fagus sylvatica L

“…For instance, associations of genetic variation with temperature and precipitation have been detected in Alnus glutinosa [ 81 ], Populus balsamifera [ 82 ], Populus trichocarpa [ 83 ], Pseudotsuga menziesii [ 84 ], Quercus lobata [ 85 ], Quercus rugosa [ 86 ], Picea abies [ 87 ], and Pinus taeda [ 33 ]. More recently, SNPs in candidate genes that may be under climate selection have been found in European beech [ 63 , 66 – 69 , 88 ], and associations between these SNPs and environmental variables such as temperature, precipitation, and drought have been determined.…”