While seedlings of large-seeded plants are considered to withstand resource restrictions and abiotic stresses more efficiently, plants with small seed sizes are considered more efficient colonizers due to their ability to produce greater numbers of seeds. On the other hand, seed size can be altered intraspecifically in response to environmental cues . Ecologists and evolutionary biologists had early observed this phenomenon. However, it is largely unknown the mechanism underlying why are seedlings of large-seeded plants considered to withstand drought stresses efficiently.
We found Arabidopsis ARF2 (Auxin Response Factor2), ANT(AINTEGUMENTA) and COR15A(COLD-REGULATED15A) are important regulators of both drought tolerance and seed mass, and the ARF2 transcription repressor negatively regulates the ANT gene through binding directly to its promoter, in turn, the ANT transcription factor positively modulates the expression of the COR15A gene by binding directly to its promoter. Genetic evidence indicates ARF2-ANT-COR15A forms ABA (abscisic acid) signaling-mediated gene cascade for regulation of both drought tolerance and seed mass, which has cross talk with the auxin signal pathway. Together, our proposed model provides a better understanding of seed mass and drought tolerance regulation, which may in turn lead to better increased crop yield and crop breeding.