The NAC transcription factor ATAF2 enhances Arabidopsis biomass and chlorophyll a accumulations at the early growth stage

Twelve-day-old plants were harvested for biomass and Chl-a/b measurements. While no significant difference of biomass or Chl-a/b accumulations was observed between the wild-type Col-0 and the loss-of-function ataf2-1/2 plants, all three ATAF2 overexpression lines (ATAF2ox-1/2/3) exhibited much higher biomass and Chl-a accumulations as compared to Col-0 and ataf2-1/2, which can at least be partially interpreted as the consequences of higher endogenous BR/IAA levels and reduced NYC1 expression, respectively. The results demonstrate the positive regulatory role of ATAF2 in biomass and Chl-a accumulations. Notably, ATAF2 overexpression does not increase Arabidopsis biomass accumulation at later growth stages, indicating its functional nature of developmental timing acceleration.