Transgenerational Reset Of Juvenility in Plants

Abstract

Multicellular organisms undergo several developmental transitions during their life cycles. In contrast to animals, the plant germline and zygote are derived from adult somatic cells. As such, the juvenility of a plant must be reset in each generation. Previous studies have demonstrated that the decline in the levels of miR156/7 with age drives plant maturation. Here, we show that the transgenerational reset of plant juvenility is mediated by de novo activation of MIR156/7 in Arabidopsis. Blocking this process leads to a shortened juvenile phase and premature flowering in the offspring. Mechanistically, we find that different MIR156/7 genes are reset at different developmental stages through distinct reprogramming routes. Among them, MIR156A and MIR156C, two major genes in the miR156 family, are re-activated by the B3 transcription factor LEC2 during the early embryonic stage. Our results delineate a robust transgenerational reset mechanism that ensures accurate restoration of the juvenile phase in each plant generation.