@article{upchurch_ramirez_2011, title={Effects of temperature during soybean seed development on defense-related gene expression and fungal pathogen accumulation}, volume={33}, ISSN={["0141-5492"]}, DOI={10.1007/s10529-011-0722-5}, abstractNote={Soybean [Glycine max (L.) Merr] plants were exposed to three temperature regimens during seed development to investigate the effect of temperature on the expression of eight defense-related genes and the accumulation of two fungal pathogens in inoculated seeds. In seeds prior to inoculation, either a day/night warm (34/26 °C) or a cool temperature (22/18 °C) relative to normal (26/22 °C) resulted in altered patterns of gene expression including substantially lower expression of PR1, PR3 and PR10. After seed inoculation with Cercospora kikuchii, pathogen accumulation was lowest in seeds produced at 22/18 °C in which of all defense genes, MMP2 was uniquely most highly induced. For seeds inoculated with Diaporthe phaseolorum, pathogen accumulation was lowest in seeds produced at 34/26 °C in which of all defense genes, PR10 was uniquely most highly induced. Our detached seed assays clearly demonstrated that the temperature regimens we applied during seed development produced significant changes in seed defense-related gene expression both pre- and post inoculation and our findings support the hypothesis that global climate change may alter plant-pathogen interactions and thereby potentially crop productivity.}, number={12}, journal={BIOTECHNOLOGY LETTERS}, author={Upchurch, Robert G. and Ramirez, Martha E.}, year={2011}, month={Dec}, pages={2397–2404} }
 @article{upchurch_ramirez_2011, title={Soybean Plastidal Omega-3 Fatty Acid Desaturase Genes GmFAD7 and GmFAD8: Structure and Expression}, volume={51}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2010.09.0537}, abstractNote={We characterized soybean [Glycine max (L.) Merr.] FAD7 and FAD8 gene structure and expression responses to temperature and pathogen stress to compare and contrast these features to those reported for higher plant plastidal omega-3 (ω-3) desaturases. We found that the genomic structure and deduced amino acid sequence of soybean FAD7 and FAD8 are similar to other higher plant plastidal w-3 desaturases: eight exons and seven introns, predicted proteins of 453 amino acid residues containing three conserved histidine motifs, amino terminal chloroplast transit peptides, and molecular masses of 51.3 and 51.4 kDa, respectively. GmFAD7 has 76% amino acid sequence identity to GmFAD8. Two complete copies of GmFAD7, one on chromosome 18 and one on chromosome 7, and two complete copies of GmFAD8, one on chromosome 3 and one on chromosome 1 of the 'Williams 82' soybean genome, were found with strong sequence similarity to GmFAD7 and GmFAD8 of cultivar Dare. Dare GmFAD7 transcript expression in leaves remained at a relatively low level and was unaffected by any of the temperature treatments we imposed, but GmFAD8 transcript accumulation was sharply upregulated by a cool temperature (20/16°C day/night) after a 12 h exposure and total linolenic acid as a percent of total leaf fatty acids increased from 60 to about 68% after 48 h at the cool temperature. Inoculation of soybean leaves with the fungal pathogen Cercospora kikuchii differentially upregulated the level of GmFAD7 transcripts to twice that of GmFAD8 by 12 h postinoculation. The response of soybean foliar FAD8 expression and linolenic acid levels to cool temperature was similar to observations in other plants. On the other hand, despite increased soybean FAD7 expression in response to foliar pathogen stress the expected associated increase in foliar linolenic acid was not detected.}, number={4}, journal={CROP SCIENCE}, author={Upchurch, Robert G. and Ramirez, Martha E.}, year={2011}, month={Jul}, pages={1673–1682} }
 @article{upchurch_ramirez_2010, title={Gene Expression Profiles of Soybeans with Mid-Oleic Acid Seed Phenotype}, volume={87}, ISSN={["0003-021X"]}, DOI={10.1007/s11746-010-1576-z}, abstractNote={Abstract}, number={8}, journal={JOURNAL OF THE AMERICAN OIL CHEMISTS SOCIETY}, author={Upchurch, Robert G. and Ramirez, Martha E.}, year={2010}, month={Aug}, pages={857–864} }
 @article{zhang_burton_upchurch_whittle_shanklin_dewey_2008, title={Mutations in a Delta(9)-Stearoyl-ACP-Desaturase Gene Are Associated with Enhanced Stearic Acid Levels in Soybean Seeds}, volume={48}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2008.02.0084}, abstractNote={Stearic acid (18:0) is typically a minor component of soybean [Glycine max (L.) Merr.] oil, accounting for only 2 to 4% of the total fatty acid content. Increasing stearic acid levels of soybean oil would lead to enhanced oxidative stability, potentially reducing the need for hydrogenation, a process leading to the formation of undesirable trans fatty acids. Although mutagenesis strategies have been successful in developing soybean germplasm with elevated 18:0 levels in the seed oil, the specific gene mutations responsible for this phenotype were not known. We report a newly identified soybean gene, designated SACPD‐C, that encodes a unique isoform of Δ9–stearoyl‐ACP‐desaturase, the enzyme responsible for converting stearic acid to oleic acid (18:1). High levels of SACPD‐C transcript were only detected in developing seed tissue, suggesting that the encoded desaturase functions to enhance oleic acid biosynthetic capacity as the immature seed is actively engaged in triacylglycerol production and storage. The participation of SACPD‐C in storage triacylglycerol synthesis is further supported by the observation of mutations in this gene in two independent sources of elevated 18:0 soybean germplasm, A6 (30% 18:0) and FAM94‐41 (9% 18:0). A molecular marker diagnostic for the FAM94‐41 SACPD‐C gene mutation strictly associates with the elevated 18:0 phenotype in a segregating population, and could thus serve as a useful tool in the development of cultivars with oils possessing enhanced oxidative stability.}, number={6}, journal={CROP SCIENCE}, author={Zhang, Ping and Burton, Joseph W. and Upchurch, Robert G. and Whittle, Edward and Shanklin, John and Dewey, Ralph E.}, year={2008}, pages={2305–2313} }
 @article{xue_upchurch_kwanyuen_2008, title={Relationships between oleic and linoleic acid content and seed colonization by Cercospora kikuchii and Diaporthe phaseolorum}, volume={92}, ISSN={["1943-7692"]}, DOI={10.1094/PDIS-92-7-1038}, abstractNote={ Compared with standard cultivars, seed of mid-oleic soybean genotypes sometimes have shown increased colonization by Cercospora kikuchii in the field as judged by increased levels of purple-stained seed. To examine relationships between oleic and linoleic acid levels in soybean seed and postharvest seed colonization by two fungal seed pathogens, we inoculated seed with differing oleic:linoleic acid (O/L) ratios. Seed with defined O/L ratios were produced by allowing seed development of two isogenic soybean lines to occur in three different air temperature environments. Seed produced in these environments were harvested, individually analyzed for fatty acid composition, and inoculated with mycelium preparations of the fungal seed pathogens C. kikuchii or Diaporthe phaseolorum var. sojae. Fungal biomass of infected seed was quantified by measuring in vitro ergosterol content. For both soybean lines, colonization by C. kikuchii was positively correlated with the O/L ratio (r = 0.55, P < 0.03) and oleic acid content (r = 0.61, P < 0.02), and negatively correlated with linoleic (r = –0.60, P < 0.02) and linolenic (r = –0.58, P < 0.03) acid content. No association was found between the extent of seed colonization by D. phaseolorum and the seed O/L ratio. Our data suggest that the O/L ratio may be related to soybean seed colonization by C. kikuchii, but there is no evidence of a relationship with D. phaseolorum var. sojae colonization. }, number={7}, journal={PLANT DISEASE}, author={Xue, H. Q. and Upchurch, R. G. and Kwanyuen, P.}, year={2008}, month={Jul}, pages={1038–1042} }
 @article{byfield_upchurch_2007, title={Effect of temperature on delta-9 stearoyl-ACP and microsomal omega-6 desaturase gene expression and fatty acid content in developing soybean seeds}, volume={47}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2006.04.0213}, abstractNote={Delta‐9 stearoyl‐ACP (SAD) and microsomal omega‐6 oleate (FAD2) desaturases contribute to the maintenance of lipid fluidity in membranes and the fatty acid composition of storage lipids in seed. Since these enzymes must operate at varying environmental temperatures, they are under constitutive control, but they may also be subject to fine regulation both transcriptionally and posttranscriptionally. We measured transcript accumulation of the seed‐expressed SAD‐A and SAD‐B and FAD2‐1A and FAD2‐1B genes in the seeds of three soybean varieties grown at cool (22/18°C), normal (26/22°C), or warm (30/26°C) temperatures during pod fill. At the cool temperature, transcript accumulation of both the SAD and FAD2‐1 genes was significantly elevated, with FAD2‐1B 2‐ to 10‐fold or greater than FAD2‐1A at 35 d after flowering. Expression of both SAD and FAD2‐1 were significantly decreased in seed that developed at the warm temperature. Decreased FAD2‐1 transcript accumulation at the warm temperature was positively associated with significantly increased oleic and decreased linoleic acid content in the three varieties examined. Decreased SAD transcript accumulation at the warm temperature was positively associated with a significantly increased level of stearic acid but only in the high‐stearate mutant line, A6. We conclude that environmental temperature modulates oleic and linoleic acid in developing seed through regulated FAD2‐1 gene expression, but temperature modulation of stearic acid content in wild‐type soybean may be more complex, involving in addition to SAD‐A and ‐B, plastid thioesterase genes FATA and FATB.
}, number={4}, journal={CROP SCIENCE}, author={Byfield, Grace E. and Upchurch, Robert G.}, year={2007}, pages={1698–1704} }
 @article{xue_upchurch_kwanyuen_2006, title={Ergosterol as a quantifiable biomass marker for Diaporthe phaseolorum and Cercospora kikuchii}, volume={90}, ISSN={["1943-7692"]}, DOI={10.1094/PD-90-1395}, abstractNote={ The relationship between ergosterol content and biomass was determined for the soybean fungal pathogens Diaporthe phaseolorum (Cooke & Ellis) Sacc. var. sojae, causal agent of Phomopsis seed decay, and Cercospora kikuchii (Matsumoto & Tomoy.), causal agent of leaf blight and purple seed stain. Biomass was manipulated by varying incubation period, and ergosterol was quantified by high-pressure liquid chromatography. Fungal dry mass was linearly correlated with ergosterol content (r2 = 0.90, P < 0.05 for D. phaseolorum, and r2 = 0.95, P < 0.01 for C. kikuchii). In vitro ergosterol content of fungi was 3.16 μg/mg for D. phaseolorum and 2.85 μg/mg for C. kikuchii. Ergosterol content of inoculated seed was qualitatively correlated with observed seed colonization by both pathogens. Soybean variety had a significant effect on fungal colonization by D. phaseolorum and ergosterol content. Results show that ergosterol content can be used to quantify colonization of soybean seed by both pathogens. }, number={11}, journal={PLANT DISEASE}, author={Xue, H. Q. and Upchurch, R. G. and Kwanyuen, P.}, year={2006}, month={Nov}, pages={1395–1398} }
 @article{byfield_xue_upchurch_2006, title={Two genes from soybean encoding soluble Delta 9 stearoyl-ACP desaturases}, volume={46}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2005.06-0172}, abstractNote={The Δ9 stearoyl acyl‐carrier protein desaturase (SACPD) gene of soybean [Glycine max (L.) Merrill] encodes a soluble enzyme that converts stearic to oleic acid. Understanding the regulation of SACPD expression and enzyme activity are thus important steps toward developing soybean lines with altered stearic or oleic acid content. Using primers designed to a G. max SACPD cDNA sequence, a 3648‐bp product was cloned and sequenced from the genome of cultivar Dare. Comparison of the third SACPD exon protein sequence with other available Glycine SACPD sequences revealed unique amino acid variability at positions 310 and 313. Sequence‐specific primers were designed for Real‐time RT‐PCR (reverse transcriptase‐polymerase chain reaction) for this region of exon 3. Diagnostic and specific products were recovered with these primers using Dare cDNA template and Dare genomic DNA. Sequencing of a second genomic clone from Dare confirmed that there were two SACPD genes, designated A and B, in this cultivar. Survey of the genomes of 51 soybean lines and cultivars with PCR and the gene‐specific primers indicated that all 51 had both A and B Differences between SACPD‐A and ‐B transcript abundance in soybean tissues, while quantifiable, were not dramatic. SACPD‐A and ‐B transcript accumulation for three seed developmental stages between R5 and R6 was essentially equal. Biochemical analysis of the proteins encoded by these two SACPD genes may reveal whether the amino acid variability uncovered in this study has any relation to enzyme activity.}, number={2}, journal={CROP SCIENCE}, author={Byfield, GE and Xue, H and Upchurch, RG}, year={2006}, pages={840–846} }
 @article{upchurch_rose_eweida_zuo_2005, title={Expression of the cercosporin transporter, CFP, in tobacco reduces frog-eye lesion size}, volume={27}, ISSN={["1573-6776"]}, DOI={10.1007/s10529-005-1780-3}, abstractNote={The cercosporin Major Facilitator Superfamily (MFS) transporter, CFP, under the control of the CaMV 35S promoter, was introduced into the Xanthi cultivar of tobacco by Agrobacterium-mediated transformation. CFP(+) transgenic plants were physically indistinguishable from non-transgenic Xanthi and progressed normally through growth to seed set. Accumulation of CFP in the leaf membrane fraction of CFP(+ )transgenic plants was associated with decreased cercosporin phytotoxicity. Frog-eye leaf lesions on CFP(+ )transgenic plants infected with Cercospora nicotianae conidia were smaller but were similar in number to those on non-transgenic plants. We conclude that transgenic expression of CFP may have relevance for a disease control strategy in Cercospora-plant pathosystems where cercosporin is implicated in pathogen virulence.}, number={20}, journal={BIOTECHNOLOGY LETTERS}, author={Upchurch, RG and Rose, MS and Eweida, M and Zuo, WN}, year={2005}, month={Oct}, pages={1543–1550} }
 @article{kuykendall_upchurch_2004, title={Expression in sugar beet of the introduced cercosporin toxin export (CFP) gene from Cercospora kikuchii, the causative organism of purple seed stain in soybean}, volume={26}, ISSN={["0141-5492"]}, DOI={10.1023/B:BILE.0000024096.22105.c3}, abstractNote={The Cercospora kikuchii cercosporin export gene, CFP, introduced into Beta vulgaris L. by conjugation with Rhizobium radiobacter, was stably maintained during vegetative propagation as verified by PCR using primers specific for the CFP gene. Transcriptional expression of the CFP gene in leaves was determined by RT-PCR using CFP-specific primers. CFP protein was detected using Western analysis with an affinity-purified polypeptide-specifc antibody. Analysis of the relative susceptibility of CFP-transgenic and non-transgenic sugar beet plants is planned but will probably take several years to complete.}, number={9}, journal={BIOTECHNOLOGY LETTERS}, author={Kuykendall, LD and Upchurch, RG}, year={2004}, month={May}, pages={723–727} }
 @article{upchurch_rose_eweida_callahan_2002, title={Transgenic assessment of CFP-mediated cercosporin export and resistance in a cercosporin-sensitive fungus}, volume={41}, ISSN={["0172-8083"]}, DOI={10.1007/s00294-002-0280-4}, abstractNote={Cercosporin is a toxic polyketide produced by many phytopathogenic members of the fungal genus Cercospora. Cercospora species, themselves, exhibit the highest level of self-resistance to this almost universally toxic photosensitizer. Although the mechanism of cercosporin self-resistance is multi-faceted, partial resistance does appear to be provided by the encoded product of CFP ( cercosporin facilitator protein), a gene recently isolated from the pathogen of soybean, C. kikuchii. CFP has significant similarity to the major facilitator superfamily of integral membrane transport proteins. We expressed CFP in the cercosporin non-producing, cercosporin-sensitive fungus, Cochliobolus heterostrophus, in order to assess the transport activity of CFP and the contribution of CFP to cercosporin resistance in a fungal species free of endogenous toxin production. Expression of the CFP transgene in this fungus results in increased resistance to cercosporin due, apparently, to its export out of the fungus.}, number={1}, journal={CURRENT GENETICS}, author={Upchurch, RG and Rose, MS and Eweida, M and Callahan, TM}, year={2002}, month={Apr}, pages={25–30} }
 @article{upchurch_rose_eweida_2001, title={Over-expression of the cercosporin facilitator protein, CFP, in Cercospora kikuchii up-regulates production and secretion of cercosporin}, volume={204}, ISSN={["0378-1097"]}, DOI={10.1111/j.1574-6968.2001.tb10868.x}, abstractNote={CFP (cercosporin facilitator protein), a light-regulated gene from the soybean fungal pathogen Cercospora kikuchii, encodes the putative major facilitator transporter of the fungal polyketide cercosporin. Gene disruption of CFP in C. kikuchii strain Gus-3 resulted in dramatically reduced cercosporin production and virulence, and increased sensitivity to the toxin. Two C. kikuchii transformant strains (10-1 and 10-11) that over-produce cercosporin were recovered from the complementation of CFP gene-disrupted strain Gus-3. Southern analysis revealed that these strains contained multiple genomic copies of CFP and over-expressed CFP transcript and protein. Although 10-1 and 10-11 produce and secrete significantly elevated levels of cercosporin, they exhibit wild-type resistance to cercosporin, and maintain a wild-type pattern of light-regulated toxin accumulation. Restoration of wild-type cercosporin resistance in 10-1 and 10-11 suggests that CFP does contribute substantially to cercosporin resistance via toxin secretion. The three-fold increase in toxin accumulation, predominantly associated with the mycelium fraction of these CFP multi-copy strains, suggests that CFP may also have a significant, but unknown, role in regulating toxin production.}, number={1}, journal={FEMS MICROBIOLOGY LETTERS}, author={Upchurch, RG and Rose, MS and Eweida, M}, year={2001}, month={Oct}, pages={89–93} }
 @misc{upchurch_callahan_ehrenshaft_2000, title={Fungal gene encoding resistance to the phytotoxin cercosporin}, volume={6,077,995}, number={2000 June 20}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Upchurch, R. G. and Callahan, T. M. and Ehrenshaft, M.}, year={2000} }
 @article{callahan_rose_meade_ehrenshaft_upchurch_1999, title={CFP, the putative cercosporin transporter of Cercospora kikuchii, is required for wild type cercosporin production, resistance, and virulence on soybean}, volume={12}, ISSN={["1943-7706"]}, DOI={10.1094/MPMI.1999.12.10.901}, abstractNote={ Many species of the fungal genus Cercospora, including the soybean pathogen C. kikuchii, produce the phytotoxic polyketide cercosporin. Cercosporin production is induced by light. Previously, we identified several cDNA clones of mRNA transcripts that exhibited light-enhanced accumulation in C. kikuchii. Targeted disruption of the genomic copy of one of these, now designated CFP (cercosporin facilitator protein), results in a drastic reduction in cercosporin production, greatly reduced virulence of the fungus to soybean, and increased sensitivity to exogenous cercosporin. Sequence analysis of CFP reveals an 1,821-bp open reading frame encoding a 65.4-kDa protein similar to several members of the major facilitator superfamily (MFS) of integral membrane transporter proteins known to confer resistance to various antibiotics and toxins in fungi and bacteria. We propose that CFP encodes a cercosporin transporter that contributes resistance to cercosporin by actively exporting cercosporin, thus maintaining low cellular concentrations of the toxin. }, number={10}, journal={MOLECULAR PLANT-MICROBE INTERACTIONS}, author={Callahan, TM and Rose, MS and Meade, MJ and Ehrenshaft, M and Upchurch, RG}, year={1999}, month={Oct}, pages={901–910} }
 @book{elkan_upchurch_1997, title={Current issues in symbiotic nitrogen fixation: Selected papers of the 15th North American Conference on Symbiotic Nitrogen Fixation held at North Carolina State University, Raleigh, NC, USA, 13-17 August 1995}, publisher={Dordrecht; London: Kluwer Academic}, author={Elkan, Gerald H. and Upchurch, R. G.}, year={1997} }
 @article{upchurch_1995, title={Genetic regulation of cercosporin production in Cercospora kikuchii}, volume={72}, ISSN={["0003-021X"]}, DOI={10.1007/BF02577834}, abstractNote={Abstract}, number={12}, journal={JOURNAL OF THE AMERICAN OIL CHEMISTS SOCIETY}, author={Upchurch, RG}, year={1995}, month={Dec}, pages={1435–1438} }
 @article{upchurch_meade_hightower_thomas_callahan_1994, title={Transformation of the fungal soybean pathogen Cercospora kikuchii with the selectable marker bar}, volume={60}, number={12}, journal={Applied and Environmental Microbiology}, author={Upchurch, R. G. and Meade, M. J. and Hightower, R. C. and Thomas, R. S. and Callahan, T. M.}, year={1994}, pages={4592} }
 @misc{zablotowicz_upchurch_ligon_1989, title={Bradyrhizobium japonicum mutants exhibiting superior soybean nodulation}, volume={4,863,866}, number={1989 Sep. 5}, publisher={Washington, DC: U.S. Patent and Trademark Office}, author={Zablotowicz, R. M. and Upchurch, R. G. and Ligon, J. M.}, year={1989} }
 @article{upchurch_elkan_1978, title={AMMONIA ASSIMILATION IN RHIZOBIUM-JAPONICUM COLONIAL DERIVATIVES DIFFERING IN NITROGEN-FIXING EFFICIENCY}, volume={104}, ISSN={["0022-1287"]}, DOI={10.1099/00221287-104-2-219}, abstractNote={SUMMARY: Ammonia assimilatory activities were investigated in cultures of small, efficient nitrogen-fixing derivatives (110-I, 76-NS) and large, inefficient nitrogen-fixing derivatives (110-L1, 76-s) of Rhizobium japonicum strains 3I1b110 and 61A76. Specific activities of the key ammonia assimilatory enzymes, glutamine synthetase (EC 6.3.1.2), glutamate synthase (EC 2.6.1.53) and glutamate dehydrogenase (EC 1.4.1.2), were determined in aerobic, microaerophilic and bacteroid cell-free extracts. In aerobic culture, 110-L1 and 76-s assimilated more ammonia than 110-I and 76-NS because of apparent twofold or greater assimilatory enzyme activities. Specific ammonia assimilatory enzyme activities were 10- to 100-fold lower for all derivatives in nitrogen-fixing microaerophilic and bacteroid cultures. In addition to these already low ammonia assimilatory activities, the assimilatory activities of 110-I and 76-NS were twofold lower than those of 110-L1 and 76-s. The small colony types also excreted ammonia under nitrogen-fixing conditions.
These findings support the idea that rhizobia can simultaneously derepress nitrogenase biosynthesis whilst repressing ammonia assimilatory enzyme biosynthesis. This investigation has also linked the efficiency of ammonia assimilation with the efficiency of nitrogenase activity as an inverse function, i.e. those R. japonicum derivatives that fix greater amounts of nitrogen also assimilate less fixed nitrogen.}, number={FEB}, journal={JOURNAL OF GENERAL MICROBIOLOGY}, author={UPCHURCH, RG and ELKAN, GH}, year={1978}, pages={219–225} }