@article{herrero_gonzalez_gillikin_velez_daub_2011, title={Identification and characterization of a pyridoxal reductase involved in the vitamin B6 salvage pathway in Arabidopsis}, volume={76}, ISSN={["1573-5028"]}, DOI={10.1007/s11103-011-9777-x}, abstractNote={Vitamin B6 (pyridoxal phosphate) is an essential cofactor in enzymatic reactions involved in numerous cellular processes and also plays a role in oxidative stress responses. In plants, the pathway for de novo synthesis of pyridoxal phosphate has been well characterized, however only two enzymes, pyridoxal (pyridoxine, pyridoxamine) kinase (SOS4) and pyridoxamine (pyridoxine) 5' phosphate oxidase (PDX3), have been identified in the salvage pathway that interconverts between the six vitamin B6 vitamers. A putative pyridoxal reductase (PLR1) was identified in Arabidopsis based on sequence homology with the protein in yeast. Cloning and expression of the AtPLR1 coding region in a yeast mutant deficient for pyridoxal reductase confirmed that the enzyme catalyzes the NADPH-mediated reduction of pyridoxal to pyridoxine. Two Arabidopsis T-DNA insertion mutant lines with insertions in the promoter sequences of AtPLR1 were established and characterized. Quantitative RT-PCR analysis of the plr1 mutants showed little change in expression of the vitamin B6 de novo pathway genes, but significant increases in expression of the known salvage pathway genes, PDX3 and SOS4. In addition, AtPLR1 was also upregulated in pdx3 and sos4 mutants. Analysis of vitamer levels by HPLC showed that both plr1 mutants had lower levels of total vitamin B6, with significantly decreased levels of pyridoxal, pyridoxal 5'-phosphate, pyridoxamine, and pyridoxamine 5'-phosphate. By contrast, there was no consistent significant change in pyridoxine and pyridoxine 5'-phosphate levels. The plr1 mutants had normal root growth, but were significantly smaller than wild type plants. When assayed for abiotic stress resistance, plr1 mutants did not differ from wild type in their response to chilling and high light, but showed greater inhibition when grown on NaCl or mannitol, suggesting a role in osmotic stress resistance. This is the first report of a pyridoxal reductase in the vitamin B6 salvage pathway in plants.}, number={1-2}, journal={PLANT MOLECULAR BIOLOGY}, author={Herrero, Sonia and Gonzalez, Eugenia and Gillikin, Jeffrey W. and Velez, Heriberto and Daub, Margaret E.}, year={2011}, month={May}, pages={157–169} } @article{gonzalez_sutton_correll_2006, title={Clarification of the etiology of Glomerella leaf spot and bitter rot of apple caused by Colletotrichum spp. based on morphology and genetic, molecular, and pathogenicity tests}, volume={96}, ISSN={["1943-7684"]}, DOI={10.1094/PHYTO-96-0982}, abstractNote={ Morphological characteristics and vegetative compatibility groups (VCGs) of 486 isolates of Glomerella cingulata, Colletotrichum gloeosporioides, and C. acutatum collected from apple leaves with Glomerella leaf spot (GLS) symptoms and fruit with bitter rot symptoms in the United States and Brazil were studied. From this collection, 155 isolates of G. cingulata (93 from fruit, 61 from leaves, and 1 from buds), 42 isolates of C. gloeosporioides from fruit, and 14 isolates of C. acutatum (10 from fruit and 4 from leaves) were studied using mitochondrial (mt)DNA restriction fragment length polymorphism (RFLP) haplotypes. A subset of 24 isolates was studied by examining the sequence of a 200-bp intron of the glyceraldehyde 3-phosphate dehydrogenase (GDPH) nuclear gene. In addition, 98 isolates were tested for pathogenicity on leaves of cvs. Gala and Golden Delicious in the greenhouse, and 24 isolates were tested for pathogenicity on fruit of cv. Gala in growth chambers. In total, 238 and 225 isolates of G. cingulata were separated into four distinct morphological types and six VCGs, respectively. Five morphological types and six VCGs were identified among 74 and 36 isolates of C. gloeosporioides, respectively. Three morphological types and four VCGs were identified among 74 and 23 isolates of C. acutatum, respectively. Seven different mtDNA RFLP haplotypes were observed within isolates of G. cingulata, two within isolates of C. gloeosporioides, and two within isolates of C. acutatum. Phylogenetic trees, inferred based on maximum likelihood and maximum parsimony methods using the intron sequence, produced similar topologies. Each species was separated into distinct groups. All isolates tested were pathogenic on fruit, though only isolates with specific VCGs and haplotypes were pathogenic to leaves. Vegetative compatibility was a better tool than molecular characters for distinguishing isolates of G. cingulata pathogenic on both leaves and fruit from the ones pathogenic only on fruit. Isolates of G. cingulata capable of causing both GLS and bitter rot were included in haplotypes and groups based on the sequence analysis of the 200-bp intron that also included isolates capable of causing bitter rot only. Additionally, isolates of G. cingulata from the United States and Brazil which cause GLS were included in different haplotypes and sequence analysis groups. Therefore, one hypothesis is that isolates of G. cingulata from the United States capable of causing both GLS on foliage and bitter rot on fruit may have arisen independently of Brazilian isolates of G. cingulata capable of causing both GLS and bitter rot, and the two groups of isolates may represent distinct populations. }, number={9}, journal={PHYTOPATHOLOGY}, author={Gonzalez, Eugenia and Sutton, Turner B. and Correll, James C.}, year={2006}, month={Sep}, pages={982–992} } @article{gonzalez_sutton_2005, title={Differentiation of isolates of Glomerella cingulata and Colletotrichum spp. associated with Glomerella leaf spot and bitter rot of apples using growth rate, response to temperature, and benomyl sensitivity}, ISBN={1535-1025}, DOI={10.1094/php-2005-0719-01-rs}, abstractNote={ Cultural characteristics were investigated as a way to distinguish isolates of Glomerella cingulata and Colletotrichum spp. associated with Glomerella leaf spot and bitter rot of apples from those that cause only bitter rot. The growth rate, response to temperature, and benomyl sensitivity of 27 isolates of Glomerella cingulata, 12 isolates of Colletotrichum gloeosporioides, and 7 isolates of C. acutatum, collected from apple orchards located in the U.S. and Brazil and previously characterized based on morphology, vegetative compatibility, and mitochondrial DNA (mtDNA) haplotypes, were determined. These isolates represent the genetic and molecular diversity within isolates of C. gloeosporioides, C. acutatum, and G. cingulata from apples found in a previous study. Slower growth, lower optimum growth temperature, and less sensitivity to benomyl distinguished isolates of C. acutatum from isolates of G. cingulata and C. gloeosporioides. However, growth rate and benomyl sensitivity were not useful for distinguishing between G. cingulata and C. gloeosporioides or differentiating isolates of G. cingulata that cause leaf spot and bitter rot from those that only cause bitter rot. }, journal={Plant Health Progress}, author={Gonzalez, E. and Sutton, T. B.}, year={2005}, pages={1} } @article{gonzalez_sutton_2004, title={Population diversity within isolates of Colletotrichum spp. causing Glomerella leaf spot and bitter rot of apples in three orchards in north Carolina}, volume={88}, ISSN={["1943-7692"]}, DOI={10.1094/PDIS.2004.88.12.1335}, abstractNote={ The population diversity within isolates of Glomerella cingulata and Colletotrichum spp. associated with Glomerella leaf spot and bitter rot of apples was studied in an orchard of cv. Granny Smith located in Wilkes County, NC, and one orchard each of cultivars Granny Smith and Gala located in Lincoln County, NC. Morphological characters and vegetative compatibility groups (VCGs) were used to determine diversity within the species. The relative frequencies of the morphological types found within each species in each orchard were also determined. G. cingulata was the predominant species associated with bitter rot in the three orchards and Glomerella leaf spot in the Gala orchard. In the three orchards, different morphological types were observed within isolates of G. cingulata and Colletotrichum acutatum, but not within isolates of Colletotrichum gloeosporioides. Isolates of C. gloeosporioides were not found in the orchard of cv. Granny Smith in Lincoln County. In the other two orchards, C. gloeosporioides represented the lowest proportion of the population. Three VCGs were found among isolates of G. cingulata (VCG-1, 2, and 6), two among isolates of C. gloeosporioides (VCG-9 and 10), and two among isolates of C. acutatum (VCG-15 and 16). VCGs 2, 6, 9, 10, 15, and 16 were found in the Granny Smith orchard in Wilkes County, VCGs 1, 2, and 6 in the Gala orchard in Lincoln County, and VCGs 2 and 6 in the Granny Smith orchard in Lincoln County. Differences in frequencies among the different morphological types found within the three orchards remained relatively similar throughout the season and from year to year, suggesting that the relative frequencies of G. cingulata, C. gloeosporioides, and C. acutatum remain stable in an orchard once the fungi are established. }, number={12}, journal={PLANT DISEASE}, author={Gonzalez, E and Sutton, TB}, year={2004}, month={Dec}, pages={1335–1340} } @article{gonzalez_sutton_1999, title={First report of Glomerella leaf spot (Glomerella cingulata) of apple in the United States}, volume={83}, number={11}, journal={Plant Disease}, author={Gonzalez, E. and Sutton, T. B.}, year={1999}, pages={1074} }