Research

Plant Developmental Genetics

Dr. John Golz

Throughout their life plants are continually generating new organs from groups of undifferentiated cells called meristems.  This occurs both underground with the formation of new roots and aerially, with leaves and then flowers arising from the growing shoot tip. 

The advantage of post-embryonic development is that it gives plants the flexibility to respond to changes in the local environment by modifying either the number and/or the size of their organs.  For instance a plant may respond to a sudden break in the canopy cover by sending out a branch towards this new source of light.  Plant growth is therefore under complex control both by external factors such as nutrient and light availability, and internally from the plants own developmental program.  Ultimately all of these factors feed into pathways that influence the timing of organ formation and the extent of cell division and expansion during organ development.  Given the importance of organ growth for crop productivity it is perhaps surprising that relatively little is known about the genetic pathways that regulate the size and shape of plant organs such as leaves and the fruit forming organs.

An exciting recent advance in this area has shown that the formation of distinct cell types in the top and bottom halves of leaves is required to initiate growth along the width of the organ.  For instance plants lacking either top or bottom cell types have radially symmetric needle like organs. 

My group is interested in understanding how organ growth, particularly leaf growth, is regulated in the model plant Arabidopsis thaliana.  One approach we are taking is to identify the growth promoting genes that are switched on following the establishment of cell identities in the developing leaf.  Our studies have initially focused on the YABBYs, a family of plant specific transcription factors expressed in the bottom side of the leaves that are thought to promote blade growth.

The aims of our research are to:

• Understand how the YABBY family of transcription factors regulate leaf growth
• Understand how hormones such as auxin interact with the YABBY pathway to determine the extent of leaf growth  
• Understand how changes in the environment influence the genetic pathways regulating leaf growth.

Arabidopsis Links:

http://www.nsf.gov/pubs/2002/bio0202/start.htm

http://www.arabidopsis.org/

Recent Publications

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