Evolution, expression patterns, and functional characterization of MADS32 in grasses

GIGENA VIRGINIA;; REINHEIMER R.

Congreso; RAFV Conference; 2021

Grass family differs from other angiosperms because of their modified flowers. Grass flowers lack of the conventional sepals and petals, having instead two bract-like organs called lemma and palea. The homology of the lemma and palea is yet a theme of discussion. To understand the identity of these novel organs we study the molecular evolution, expression patterns, and perform the functional characterization of MADS32, a MIKC-type MADS-box transcription factor with a known function in the marginal zone of the rice palea. The phylogenetic reconstruction showed that MADS32 is present in basal angiosperms and monocots. Based on RT-PCR assays we found that MADS32 is expressed in several plant organs, in particular in young inflorescences. To understand the role of MADS32 during development we study the overexpression of the MADS32 homolog from Setaria viridis on the model species Arabidopsis thaliana. The phenotypes of the overexpressing lines showed variations in several stages of vegetative and reproductive development. Interestingly, the flowers of the transgenic lines presented fused sepals indicating genetic evidence on the homology of the palea with the sepals of dicotyledons.