Molecular integrity of chloroplast DNA and mitochondrial DNA in mesophyll and bundle sheath cells of maize.

When compared to maize mesophyll cells, the plastid and mitochondrial DNAs in bundle sheath cells are less fragmented, less damaged, and contain fewer DNA polymerase-blocking impediments. Plants that conduct C4 photosynthesis differ from those that employ C3 photosynthesis with respect to leaf anatomy, biochemical pathways, and the proteins and RNA transcripts present in the leaf mesophyll (M) and bundle sheath (BS) cells. Here, we investigate the organellar DNA (orgDNA) from plastids and mitochondria in these two cell types.

Changes in DNA damage, molecular integrity, and copy number for plastid DNA and mitochondrial DNA during maize development.

The amount and structural integrity of organellar DNAs change during plant development, although the mechanisms of change are poorly understood. Using PCR-based methods, we quantified DNA damage, molecular integrity, and genome copy number for plastid and mitochondrial DNAs of maize seedlings. A DNA repair assay was also used to assess DNA impediments.

The amount and integrity of mtDNA in maize decline with development.

In maize and other grasses there is a developmental gradient from the meristematic cells at the base of the stalk to the differentiated cells at the leaf tip. This gradient presents an opportunity to investigate changes in mitochondrial DNA (mtDNA) that accompany growth under light and dark conditions, as done previously for plastid DNA. Maize mtDNA was analyzed by DAPI-DNA staining of individual mitochondria, gel electrophoresis/blot hybridization, and real-time qPCR.

Distinguishing authentic mitochondrial and plastid DNAs from similar DNA sequences in the nucleus using the polymerase chain reaction.

DNA sequences similar to those in the organellar genomes are also found in the nucleus. These non-coding sequences may be co-amplified by PCR with the authentic organellar DNA sequences, leading to erroneous conclusions. To avoid this problem, we describe an experimental procedure to prevent amplification of this "promiscuous" DNA when total tissue DNA is used with PCR.

Virus-induced gene silencing as a tool for comparative functional studies in Thalictrum.

Perennial woodland herbs in the genus Thalictrum exhibit high diversity of floral morphology, including four breeding and two pollination systems. Their phylogenetic position, in the early-diverging eudicots, makes them especially suitable for exploring the evolution of floral traits and the fate of gene paralogs that may have shaped the radiation of the eudicots. A current limitation in evolution of plant development studies is the lack of genetic tools for conducting functional assays in key taxa spanning the angiosperm phylogeny.