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要旨:
Life history and growth strategies are assumed to play an important
role in the adaptation of organisms. A. thaliana is present in many
environments across the north hemisphere. We investigated whether,
and how, the maintenance of natural variation in the growth strategies of
A. thaliana could reflect adaptation to the local environment. Drawing on
the resources from the 1001 Genome project, 451 sequenced accessions
with known climatic conditions at the collection point were phenotyped
for growth-related traits (lifecycle duration, biomass allocation, RGR,
allometric exponent) and physiological traits (net photosynthetic rate,
transpiration rate, specific leaf area). The analysis revealed that growth
strategies are constrained by a trade-off between the duration of the
lifecycle and the rate of growth, as reflected by a decrease in the allometric
exponent with flowering time. GWAS and genomic selection scans
identified a region on chromosome 2 that contains genes involved in the
secondary metabolism, and which are associated with both the variation
of the allometric exponent and the precipitation and temperature
during summer. Our results suggest that the genes modulating growth
strategies through the secondary metabolism mediate the adaptation to
the summer conditions. Interestingly, our findings also suggest that there
is selection for allometric exponents out of the three-quarter-power
law observed between species when accessions come from dry and hot environments.
