Network controlling ovule development in Arabidopsis

My PhD research focused on the role of MADS-box genes in ovule and female gametophyte development. The formation of ovule, a specialized structure that produces the female gametophyte and the progenitor of the seed, is a key step in the plant life cycle. Moreover the ovule is an excellent model system in which to study the genetic and molecular bases of plant organogenesis. Ovule development, especially in Arabidopsis, has been therefore the focus of several analysis in recent years, with many genetic pathways and regulatory mechanisms elucidated. MADS-box transcription factors, key regulators of plant development, also play a pivotal role in ovule development. We demonstrated that the MADS-box family members SEEDSTICK, SHATTERPROOF1 (SHP1), SHP2, and AGAMOUS interact with the homeodomain factor BELL1 to establish ovule identity. Moreover ovule differentiation requires the regulation of the stem cell maintenance gene WUSCHEL, repression of which is predominantly maintained by BEL1 during ovule development. We also studied the function of AGL23, a gene belonging to the recently discovered Arabidopsis Type I MADS-box subfamily. AGL23 is important to start megagametogenesis and plays a key role during embryogenesis. agl23 mutant shows, with incomplete penetrance, an arrest in embryo sac development. During embryogenesis AGL23 is involved in chloroplast biogenesis: embryos homozygous for the agl23-1 allele are completely white (albino), due to the absence of chloroplasts, strongly suggesting that AGL23 is a key regulator of organelle biogenesis.