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About the lab

Research interests: Plant development; role of MADS-domain factors in control of the transition to flowering and pollen development; protein targeting in chloroplasts

Research synopsis:

MADS-domain factors

MADS-box factors act as “master regulators” in plant development and related factors can have partially overlapping functions.  To uncover these functions, we have created mutant combinations that affect multiple genes (up to 4 or 5) in Arabidopsis. We have found particular combinations that lead to premature flowering under particular environmental conditions, show altered leaf morphologies, or result in reduced pollen performance.  We are investigating the basis of these effects through a combination of genetics and molecular biology.

 Our lab is taking a molecular approach to the study of plant development, with a focus on the processes of embryogenesis, pollen development, and flowering time. We want to know: What are the factors that cause a plant to flower at the most favorable time of the year? What are the factors that give a pollen grain the ability to navigate to an unfertilized ovule? An important component to both of these processes is the careful regulation of gene expression within specific cells of the plant. Much of our current work in these areas is focused on understanding the roles of MADS-domain transcription factors, proteins that regulate gene expression by binding directly to DNA. Much of our work is carried out using Arabidopsis thaliana, a model plant species.

45 MADS-domain proteins in the Arabidopsis genome contain a protein-binding domain (K-domain) in addition to a DNA-binding domain. These proteins have been shown to interact with each other to form multimeric complexes that can act to promote or inhibit the expression of target genes. The complexes they form can act as important regulators of floral organ development, meristem identity, flowering time, the growth of lateral roots, and fruit and ovule development.  Click on the links below to read more about ongoing projects in the lab.

Figure: The domain structure of a typical MIKC-type MADS-domain protein, and an example of a known MADS-domain tetramer that promotes anther cell identity at the floral meristem.


Flowering time regulation
AGL15 is a MIKC^C-type MADS-domain protein that is preferentially expressed in developing embryos, and acts as an inhibitor of flowering. AGL18, a related protein, is abundantly expressed throughout the plant, and has a role that is functionally redundant. We are investigating the roles of these proteins and their targets using molecular biology and genetics tools such as T-DNA insertion mutants.

Pollen development
We are investigating the regulatory roles of six divergent MADS-box genes, refered to as MIKC*-type genes.  MIKC* genes are expressed during the late stages of pollen development, and are important regulators in pollen.


Chloroplast membrane trafficking
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Recent Publications

Adamczyk, B.J. and D.E. Fernandez (2009). MIKC* MADS-domain heterodimers are required for pollen maturation and tube growth in Arabidopsis. Plant Physiol. 149: 1713-1723.

Adamczyk, B.J., Lehti-Shiu, M.D., and D.E. Fernandez (2007). The MADS-domain factors AGL15 and AGL18 act redundantly as repressors of the floral transition in Arabidopsis. Plant J. 50: 1007-1019.

Lehti-Shiu, M.D., B.J. Adamczyk, and D.E. Fernandez (2005). Expression of MADS-box genes during the embryonic phase inArabidopsis. Plant Mol. Biol. 58: 89-107.

 Sharkey, T.D., S.Yeh, A.E. Wiberley, T.G. Falbel, D. Gong, and D.E. Fernandez (2005). Evolution of the isoprene biosynthetic pathway in kudzu. Plant Physiol. 137: 700-712.

Harding, E.W., W. Tang, K.W. Nichols, D.E. Fernandez, and S.E. Perry (2003). Expression and maintenance of embryogenicpotential is enhanced through constitutive expression of AGAMOUS-Like 15. Plant Physiol. 133: 653-663.

Fang, S-C., and D.E. Fernandez (2002). Effect of regulated overexpression of the MADS domain factor AGL15 on flower senescence and fruit maturation. Plant Physiol. 130: 78-89.

Pischke, M.S., L. G. Jones, D. Otsuga, D.E. Fernandez, G.N. Drews, and M.R. Sussman (2002). An Arabidopsis histidine kinase is essential for megagametogenesis. Proc. Natl. Acad. Sci. (USA) 99: 15800-15805.

Fernandez, D.E., G.R. Heck, S.E. Perry, S.E. Patterson, A.B. Bleecker, and S.-C. Fang (2000). The embryo MADS domain factor AGL15 acts post-embryonically: inhibition of perianth senescence and abscission via constitutive expression. The Plant Cell 12: 183-198.

Perry, S.E., M.L. Lehti, and D.E. Fernandez (1999). The MADS-domain protein AGAMOUS-Like 15 accumulates in embryonic tissues with diverse origins. Plant Physiol. 120: 121-129.

Fernandez, D.E. (1997). Developmental basis of homeosis in precociously germinating Brassica napus embryos: phase change at the shoot apex. Development 124: 1149-1157.

Perry, S.E., K.W. Nichols, and D.E. Fernandez (1996). The MADS domain protein AGL15 localizes to the nucleus during early stages of seed development. The Plant Cell 8: 1977-1989.

Heck, G. R., S. E. Perry, K. W. Nichols, and D. E. Fernandez (1995). AGL15, a MADS domain protein expressed in developing embryos. The Plant Cell 7: 1271-1282.