University of South Carolina Columbia, South Carolina
Body of Abstract: Plants consist of fundamental units of growth called phytomers (leaf, axillary bud, node and internode), which are repeated and modified throughout shoot development at different developmental stages to give plants plasticity for survival and adaption. The floral meristem identity regulator LEAFY (LFY), organ boundary genes BLADE-ON-PETIOLE1 (BOP1), and BOP2, have been shown to suppress bract development in Arabidopsis, as mutations in these genes result in bract outgrowth. However, much less is known about the mechanisms that promote this bract outgrowth. Here, we showed that MADS-box genes SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 (SOC1), FRUITFUL (FUL), and AGAMOUS-LIKE24 (AGL24) play more dominate roles than BOP1/2 and LFY in bract suppression, and AINTEGUMENTA (ANT) and redundant AINTEGUMENTA-LIKE-6 (AIL6) are necessary for bract outgrowth in them. We also showed that misexpression of AIL6 alone is sufficient to causes bract outgrowth. Our data reveals a mechanism for bract suppression/ourgrwoth, providing insight on phytomer modification and inflorescence architecture.