The mitochondrion is the cellular site of a great number of biochemical, developmental and genetic processes with crucial implications for cell function. Though most biology students have only learned about mitochondria with regard to their role in energy metabolism, electron transport and oxidative phophorylation, mitochondria play a key role in programmed cell death, aging processes, redox status of the cell, onset of many important human diseases, and a variety of maternally inherited genetic traits. We know very little about how mitochondria evolve within the eukaryotic cell, how they were initially introduced and how they have acquired their various functions. Moreover, we find that mitochondria of higher plants are strikingly different from mitochondria of mammals in their genome structure, certain biochemical properties, and behavior within the cell. So many fascinating questions remain to be answered to understand these unusual, highly dynamic cellular compartments.

Our laboratory investigates the processes that are involved in how mitochondria replicate, recombine and repair their genetic information. We ask how they have inherited the genetic apparatus that fulfills these functions, and which aspects of these functions are shared with the chloroplast or nucleus. We have recently discovered about 30 nuclear genes that appear to play a role in mitochondrial genome maintenance functions, permitting us to take genomic and proteomic approaches to understand their role, cellular sites of action, and associating partners.

Our laboratory is also interested in the plant developmental pathways that intersect at the mitochondrion, including pathways mediating plastid development, cell cycle control, microgametogenesis, and plant stress responses. We seek to create a mitochondrial "morbidity map" that would allow us, via rearrangement of the mitochondrial genome, to interfere with mitochondrial participation in these pathways. We carry out studies of mitochondrial genome instability in the model plant species Arabidopsis thaliana, but use comparative genomic approaches for our studies in tomato, tobacco, soybean, millet and sorghum.