Hoekenga, Owen

member of graduate field

Plant Breeding

research overview

The emphasis of my research program is to understand the genetic and environmental factors that influence nutritional quality. The focus of my work at this time is to identify factors that increase iron nutritional quality in maize grain. The improvement of nutritional quality in crops is often called biofortification. We have identified a mechanism to biofortify maize grain with iron using a human cell culture bioassay developed by my collaborator Ray Glahn as a phenotyping tool. We have taken this trait data, mapped quantitative trait loci for iron nutritional quality, and created new varieties. With help from the Glahn Laboratory, we have validated our results using poultry feeding studies and will soon begin metabolomic analysis of these new varieties. The previous focus for my research was assessing unintended effects of transgenic crop improvement on plant composition, quality and performance. According to the National Agricultural Statistical Service, transgenic crops made up a majority of US acreage planted in 2007. In spite of this (or perhaps because of this), a debate exists between supporters and opponents of transgenic crops regarding the demonstrated or presumed safety of these varieties to people, animals and the environment. Two important concepts in the debate over transgenic crop safety are substantial equivalence (SE) and generally regarded as safe (GRAS). SE is the concept that a transgenic variety is so highly similar to its non-transgenic parent, that it can be considered to be the same. Opponents of transgenic crop improvement have criticized this concept for being without statistical merit or utility for risk assessment. In the plant improvement context, GRAS means that we accept that the products of conventional plant breeding (i.e., new varieties) are safe. Thus, the differences that exist between conventionally improved plant cultivars represent a threshold that is acceptable to consumers, regulators and other stakeholders. We examined the differences between conventionally and transgenically modified varieties from a standpoint of GRAS, to evaluate SE in a statistically rigorous manner. My laboratory used fruit ripening in tomato as a model system of known agronomic importance and use a number of experimental approaches.

research activities

area(s) of concentration/expertise

keywords

Biofortification; Biotechnology risk assessment; Plant-metal interactions; Maize phenomics

submitted impact statement

Characterization of unintended effects in genetically modified foods

individual publications

academic article
- Genetic and Physiological Analysis of Iron Biofortification in Maize Kernels. PLoS One. 6. 2011
- Iron biofortification of maize grain. Plant Genetic Resources. 9:327-329. 2011
- Weighted correlation network analysis (WGCNA) applied to the tomato fruit metabolome. . PLoS One. 6. 2011
- Association and linkage analysis of aluminum tolerance genes in maize. PLoS One. 5. 2010
- Natural genetic variation in selected populations of Arabidopsis thaliana is associated with ionomic differences. PLoS One. 5. 2010
- Physiological and genetic characterization of end-of-day far-red light response in maize seedlings. Plant Physiology. 154:173-186. 2010
- Using metabolomics to estimate unintended effects in transgenic crop plants: problems, promises and opportunities. Journal of Biomolecular Techniques. 19:159-166. 2008
- A member of the multidrug and toxic compound extrusion ‘MATE’ family is a major gene that confers aluminum tolerance in sorghum. Nature Genetics. 39:1156-1161. 2007
- A method for cellular localization of gene expression via quantitative in situ hybridization in plants. Plant Journal. 50:159-175. 2007
- Characterization of AtALMT1 expression in aluminum inducible malate release and its role for rhizotoxic stress tolerance in Arabidopsis thaliana. Plant Physiology. 14:843-852. 2007
- AtALMT1, which encodes a malate transporter, is identified as one of several genes critical for aluminum tolerance in Arabidopsis. Proceedings of the National Academy of Sciences of the United States of America. 103:9738-9743. 2006
- The physiology, genetics and molecular biology of plant aluminum resistance and toxicity. Plant and Soil. 274:173-202. 2005
- How do crop plants tolerate acid soils? Mechanisms of aluminum tolerance and phosphorous efficiency. Annual Review of Plant Biology. 55:459-493. 2004
- Identification and characterization of aluminum tolerance loci in Arabidopsis (Landsberg erecta x Columbia) by quantitative trait locus mapping. A physiologically simple but genetically complex trait. Plant Physiology. 132:936-948. 2003
- Mechanisms of toxic metal resistance in plants: aluminum and heavy metals. Plant and Soil. 247:109-119. 2002
- Developmental patterns of chromatin structure and DNA methylation responsible for epigenetic expression of a maize regulatory gene. Genetics. 155:1889-1902. 2000
chapter
- Mechanisms of aluminum tolerance. Root Genomics. 2011
- Maize aluminum tolerance. Handbook of Maize: Its Biology. 367-380. 2008

teaching overview

I have been interested in genetics for many years. I am also fascinated by connections, relationships and context. I try to convey my enthusiasm for genetics, plus the need for context, in my teaching.

teaching activities

service to the profession

AMERICAN CHEMICAL SOCIETY Member 2010 -
American Society for Mass Spectrometry Member 2010 -
Agronomy Society of America Member 2007 -
Crop Science Society of America Member 2007 -
American Society of Plant Biologists Member 1999 -
Sigma Xi Member 1998 -
Genetic Society of America Member 1997 -

reviewer or editor for

education and training

Ph.D. in Biological Sciences, University of Missouri 1998
University of Michigan 1992

college

CALS

research keyword

Biofortification; Biotechnology risk assessment; Plant-metal interactions; Maize phenomics

VIVO: Cornell Research & Scholarship

Hoekenga, Owen

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member of graduate field

Research

research overview

research activities

area(s) of concentration/expertise

keywords

submitted impact statement

Publications

individual publications

academic article

chapter

Teaching

teaching overview

teaching activities

Service

service to the profession

reviewer or editor for

Background

education and training

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college

research keyword