Research

Current research interests in the Vollbrecht lab include understanding molecular mechanisms of plant development and their evolution, and developing genomics tools to advance that goal. There are three, major projects in the lab.

Natural Variation and Drought Responses in Developing Maize Inflorescences

Much of our work focuses on floral shoot branching in maize as an experimental system. The tassel and ear of maize comprise an attractive system because a series of shoot apical meristem fate decisions underlies normal development, and because their accessibility and large size facilitates their use in developmental and molecular experiments that exploit a plethora of research tools available in maize. In addition, the tassel and ear produce grain that is an important food and industrial commodity, and they are excellent models for other cereals. We identify genes important for floral branching in maize, use molecular techniques to understand the function of those gene products, and examine gene function in a broad, comparative context to evaluate its relevance to changes in crops during evolution, domestication and breeding. The genetic pathway regulating floral shoot branching that we identified is unique to and conserved among the cereal crops. Current work elucidates genes involved in that pathway, and how they function in different grasses. Much of this work relies an the analysis of mutants to determine gene function, and QTL and transcript profiling approaches to identify additional genes that function in genetic pathways we identify.

Funding: NSF Plant Genome Research Program – Award #1238202
Genetic Mechanisms Regulating Inflorescence Architecture in Maize and other Cereals

Ac/Ds transposable element system

In a second project, we are generating a large collection of transposon-induced, sequence-indexed, single gene knockout lines in maize using the maize Ac/Ds transposable element system. These gene knockouts are publicly available to all researchers. Through this work we are investigating determinants of transposon insertion site specificity. Based on computational approaches including analyses of DNA structural features and a machine learning approach, we are characterizing the structural code recognized by the transposase enzyme. This work has long term relevance to transposon biology and forward and reverse genetics approaches in maize, and in general to transgenic gene targeting technologies in eukaryotic organisms.

Project web site: http://plantgdb.org/prj/AcDsTagging/index.php
Funding: NSF Plant Genome Research Program – Award #0922701
Ds Regional Mutagenesis: A Platform for Defining Gene Function in Maize – http://plantgdb.org/prj/AcDsTagging/index.php

Mechanisms that operate during the gametophyte generations of maize

Finally, we are also working to elucidate developmental and genetic mechanisms that operate during the gametophyte generations of maize. Current approaches to these questions include mutagenesis using maize tertiary trisomic lines and transposon genetics, and RNAseq transcriptome profiling of the gametophytes.

Funding: NSF Plant Genome Research Program – Award #0701731
Functional Genomics of Maize Gametophytes www.maizegametophyte.org