Fig. 3.

INT-M suppresses organ differentiation and maintains meristem activity. (A) Genes differentially expressed between int-m mutants and Bowman before floral organ differentiation (DR and TM-SM) are enriched in activities associated with floral development, phytohormone, and meristem maintenance. These selected genes are plotted at the DR, TM-SM, and StP stages. Green and purple indicate genes down- and up-regulated in the mutant relative to the wild-type Bowman. (B) HvMADS3 and HvMADS1 are precociously and ectopically expressed in the int-m mutant prior to or concurrent with the TS initiation. (C) Expression patterns of putative IM identity and meristem genes. Specifically, HvLFY, HvMADS34, HvWOX2, and HvWOX7 are localized in incipient lateral primordia (pLP) in IM and TMM. HvLFY, HvERL, and HvWOX2 are found in bracts subtending the TMM. HvMADS15 is expressed in IM, TMM, and SM. HvLOG is confined in the L1 epidermal cells of IM and TMM, while HvKN1 is restricted to non-L1 epidermal IM and TMM cells. However, no obvious temporal or spatial changes in the expression of these genes are found to correlate with TS formation in int-m mutants. (D and E) A strong reduction of SAM length in int-m coincides with the shift of an IM to a TSM at the DR stage. Significant differences (***P < 0.001) are found between VM and DR stages within each genotype using Tukey test, and between the wild-type Bowman and int-m mutants using the Dunnett's test. Each triangle in the plot represents a measurement of a biological replicate.