Minisymposium 11: Reproductive Development

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Abs # M1101: AGL80 is required for central cell and endosperm development in Arabidopsis

Presenter:	Portereiko, Michael F.       Contact Presenter
Authors	Portereiko, Michael F. (A)   Lloyd, Alan  (A)   Steffen, Joshua G. (A)   Punwani, Jayson A. (A)   Otsuga, Denichiro  (A)   Drews, Gary N. (A)
Affiliations:	(A): University of Utah

During plant reproduction, the central cell of the female gametophyte becomes fertilized to produce the endosperm, a storage tissue that nourishes the developing embryo within the seed. The molecular mechanisms controlling specification and differentiation of the central cell are poorly understood. We identified a female gametophyte mutant, female gametophyte defective111 (fem111), which is affected in central cell development. In fem111 female gametophytes, the nucleolus and vacuole fail of the central cell fail to mature properly. In addition, endosperm development is not initiated following fertilization of fem111 female gametophytes. fem111 contains a T-DNA insertion in AGAMOUS-LIKE80 (AGL80). AGL80 is a member of the MADS-box gene family, which likely encode transcription factors. AGL80 is a member of the Type I, or non-MIKC, MADS-box family. No mutant phenotype has been ascribed to any of the Type I MADS-box genes. Consistent with the predicted gene identity, an AGL80-GFP fusion protein is localized to the nucleus. Within the ovule and seed, AGL80 is expressed exclusively in the central cell and uncellularized endosperm. AGL80 is also expressed in roots, leaves, floral stems, and young flowers based on real-time RT-PCR. AGL80 is required for expression of two central cell-expressed genes, DEMETER and DD46, but not a third central cell-expressed gene, FERTILIZATION-INDEPENDENT SEED2. Together, these data suggest AGL80 functions as a transcription factor within the gene regulatory network of the central cell and controls the expression of downstream genes required for central cell development and function.