Environmental and serotiny data of Pinus halepensis

Many plants undergo adaptation to fire. Yet, as global change is
increasing fire frequency worldwide, our understanding of the genetics of
adaptation to fire is still limited. We studied the genetic basis of
serotiny (the ability to disseminate seed exclusively after fire) in the
widespread, pioneer Mediterranean conifer Pinus halepensis Mill., by
linking individual variation in serotiny presence and level to fire
frequency and to genetic polymorphism in natural populations. After
filtering steps, 885 Single Nucleotide Polymorphisms (SNPs) out of 8,000
SNPs used for genotyping were implemented to perform an in situ
association study between genotypes and serotiny presence and level. To
identify serotiny-associated loci, we performed random forest analyses of
the effect of SNPs on serotiny levels, while controlling for tree size,
frequency of wildfires, and background environmental parameters. Serotiny
showed a bimodal distribution, with serotinous trees more frequent in
populations exposed to fire in their recent history. Twenty-two SNPs found
in genes involved in stress tolerance were associated with
presence-absence of serotiny while thirty-seven found in genes controlling
for flowering were associated with continuous serotiny variation. This
study shows the high potential of P. halepensis to adapt to changing fire
regimes, benefiting from a large and flexible genetic basis of trait
variation.