Inter- and intra-species comparative analysis of drought effects on seed
Drought stress can severely affect seed characteristics and seed
metabolism during development, resulting in a grain yield reduction.
Here, we examined the effect of drought on seed characteristics and
central metabolism of seven different plant species, i.e., tomato,
pepper, and eggplant from the Solanaceae family; melon and
watermelon from the Cucurbitaceae family; maize from the
Poaceae family; and sunflowers from the Asteraceae family.
Synchronized changes of seed weight and seed size in response to drought
were observed, showing smaller seed size and lower 1000 seeds weight for
tomato and melon while larger seed size and higher 1000 seeds weight for
pepper, eggplant, maize, and sunflower. Except for watermelon, number of
seeds per plant declined in drought condition for all the species.
Principal component analysis and hierarchical clustering highlighted
differences of seed relative metabolite content due to phylogenetic
differences and different regimes of water deficit. Correlation network
analysis revealed interspecies differences in the metabolites associated
with seed traits and stress-specific metabolite coordinated behavior in
each species. The results suggest that the maintenance of seed
dimensions in droughty environments may depend on the rewiring of amino
acids and sugar metabolic network. The detected metabolic interactions
that are conserved across species shed light on phylogenetic
relationships. This comparative study expands our understanding of the
interspecific diversity of seed metabolism in response to drought and
may assist us for future breeding programs in light of climate change.