N(6)-Methyladenosine (m(6)A) represents the most prevalent internal modification on mRNA and requires a multicomponent m(6)A methyltransferase complex in mammals. How their plant counterparts determine the global m(6)A modification landscape and its molecular link to plant development remain unknown. Here we show that FKBP12 INTERACTING PROTEIN 37 KD (FIP37) is a core component of the m(6)A methyltransferase complex, which underlies control of shoot stem cell fate in Arabidopsis. The mutants lacking FIP37 exhibit massive overproliferation of shoot meristems and a transcriptome-wide loss of m(6)A RNA modifications. We further demonstrate that FIP37 mediates m(6)A RNA modification on key shoot meristem genes inversely correlated with their mRNA stability, thus confining their transcript levels to prevent shoot meristem overproliferation. Our results suggest an indispensable role of FIP37 in mediating m(6)A mRNA modification, which is required for maintaining the shoot meristem as a renewable source for continuously producing all aerial organs in plants.

The spatiotemporal architecture of inflorescences that bear flowers determines plant reproductive success by affecting fruit set and plant interaction with pollinators. The inflorescence architecture that displays great diversity across flowering plants depends on developmental decisions at inflorescence meristems. Here we report a key conserved genetic pathway determining inflorescence architecture in Arabidopsis thaliana and Oryza sativa (rice). In Arabidopsis, four MADS-box genes, SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1, SHORT VEGETATIVE PHASE, AGAMOUS-LIKE 24, and SEPALLATA 4 act redundantly and directly to suppress TERMINAL FLOWER1 (TFL1) in emerging floral meristems. This is indispensable for the well-known function of APETALA1 in specifying floral meristems and is coupled with a conformational change in chromosome looping at the TFL1 locus. Similarly, we demonstrate that the orthologs of these MADS-box genes in rice determine panicle branching by regulating TFL1-like genes. Our findings reveal a conserved regulatory pathway that determines inflorescence architecture in flowering plants.

No abstract