@article{rueschhoff_gillikin_sederoff_daub_2013, title={The SOS4 pyridoxal kinase is required for maintenance of vitamin B-6-mediated processes in chloroplasts}, volume={63}, ISSN={["0981-9428"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84872415352&partnerID=MN8TOARS}, DOI={10.1016/j.plaphy.2012.12.003}, abstractNote={Vitamin B(6) (pyridoxal 5'-phosphate and its vitamers) is an important cofactor in numerous enzymatic reactions. In spite of its importance, the consequences of altering vitamin B(6) content on plant growth and development are not well understood. This study compares two mutants for vitamin B(6)-metabolizing enzymes in Arabidopsis thaliana: a pdx1.3 mutant in the de novo synthesis pathway and a salvage pathway sos4 mutant that accumulates more vitamin B(6). We show that despite a difference in total B(6) content in leaf tissue, both mutants share similar phenotypes, including chlorosis, decreased size, altered chloroplast ultrastructure, and root sensitivity to sucrose. Assay of B(6) vitamer content from isolated chloroplasts showed that, despite differing B(6) vitamer content in whole leaf tissue, both mutants share a common deficiency in total and phosphorylated vitamers in chloroplasts. One of the splice variants of the SOS4 proteins was shown to be located in the chloroplast. Our data indicate that some of the phenotypic consequences shared between the pdx1.3 and sos4 mutants are due to B(6) deficiency in chloroplasts, and show that SOS4 is required for maintenance of phosphorylated B(6) vitamer concentrations in chloroplasts. Further, our data are consistent with a diffusion model for transport of vitamin B(6) into chloroplasts.}, journal={PLANT PHYSIOLOGY AND BIOCHEMISTRY}, author={Rueschhoff, Elizabeth E. and Gillikin, Jeffrey W. and Sederoff, Heike W. and Daub, Margaret E.}, year={2013}, month={Feb}, pages={281–291} }
 @article{nole-wilson_rueschhoff_bhatti_franks_2010, title={Synergistic disruptions in seuss cyp85A2 double mutants reveal a role for brassinolide synthesis during gynoecium and ovule development}, volume={10}, ISSN={["1471-2229"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-77956486883&partnerID=MN8TOARS}, DOI={10.1186/1471-2229-10-198}, abstractNote={The Arabidopsis SEUSS (SEU) gene encodes a transcriptional adaptor protein that is required for a diverse set of developmental events, including floral organ identity specification, as well as gynoecium, ovule and embryo development. In order to better understand the molecular mechanisms of SEUSS action we undertook a genetic modifier screen to identify seuss-modifier (sum) mutations.Screening of M2 lines representing approximately 5,000 M1 individuals identified mutations that enhance the seuss mutant phenotypic disruptions in ovules and gynoecia; here we describe the phenotype of the sum63 mutant and enhanced disruptions of ovule and gynoecial development in the seu sum63 double mutant. Mapping and genetic complementation tests indicate that sum63 is allelic to CYP85A2 (AT3G30180) a cytochrome p450 enzyme that catalyzes the final steps in the synthesis of the phytohormone brassinolide.Our identification of mutations in CYP85A2 as enhancers of the seuss mutant phenotype suggests a previously unrecognized role for brassinolide synthesis in gynoecial and ovule outer integument development. The work also suggests that seuss mutants may be more sensitive to the loss or reduction of brassinolide synthesis than are wild type plants.}, journal={BMC PLANT BIOLOGY}, author={Nole-Wilson, Staci and Rueschhoff, Elizabeth E. and Bhatti, Huda and Franks, Robert G.}, year={2010}, month={Sep} }
 @article{densiow_rueschhoff_daub_2007, title={Regulation of the Arabidopsis thaliana vitamin B-6 biosynthesis genes by abiotic stress}, volume={45}, ISSN={["0981-9428"]}, DOI={10.1016/j.plaphy.2007.01.007}, abstractNote={Vitamin B6 (pyridoxine and its vitamers) plays an essential role as a co-factor for enzymatic reactions and has also recently been implicated in defense against cellular oxidative stress. The biosynthetic pathway was thoroughly characterized in Escherichia coli, however most organisms, including plants, utilize an alternate pathway involving two genes, PDX1 and PDX2. Arabidopsis thaliana contains one copy of PDX2, but three full-length copies of PDX1, one each on chromosomes 2, 3, and 5 (referred to as PDX1.1, PDX1.2, and PDX1.3, respectively). Phylogenetic analysis of the PDX1 homologues in A. thaliana showed that PDX1.1 and PDX1.3 clustered with the homologues from the other dicots, whereas PDX1.2 was more divergent, and did not cluster with either the dicots or monocots. Expression analysis using quantitative PCR showed that PDX1.1 and PDX1.3 were highly expressed in A. thaliana rosettes, while PDX1.2 showed only low level expression. All three PDX1 genes and PDX2 were responsive to abiotic stressors including high light, chilling, drought, and ozone, however, the response of PDX1.2 was disparate from that of the other PDX genes, showing a lessened response to high light, chilling, and drought, but an increased response to ozone. Green fluorescent protein fusion studies demonstrated that PDX2 localizes in the nucleus and membranes of cells, consistent with recent published data for PDX1. Insight into regulation of the biosynthetic genes during abiotic stress could have important applications in the development of stress-tolerant crops.}, number={2}, journal={PLANT PHYSIOLOGY AND BIOCHEMISTRY}, author={Densiow, Sheri A. and Rueschhoff, Elizabeth E. and Daub, Margaret E.}, year={2007}, month={Feb}, pages={152–161} }