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Tifton, GA, United States

Wang M.L.,U.S. Department of Agriculture | Chen C.Y.,Auburn University | Tonnis B.,U.S. Department of Agriculture | Barkley N.A.,U.S. Department of Agriculture | And 6 more authors.
Journal of Agricultural and Food Chemistry | Year: 2013

Peanut seeds contain high amounts of oil and protein as well as some useful bioactive phytochemicals which can contribute to human health. The U.S. peanut mini-core collection is an important genetic resource for improving seed quality and developing new cultivars. Variability of seed chemical composition within the mini-core was evaluated from freshly harvested seeds for two years. Oil, fatty acid composition, and flavonoid/resveratrol content were quantified by NMR, GC, and HPLC, respectively. Significant variability was detected in seed chemical composition among accessions and botanical varieties. Accessions were further genotyped with a functional SNP marker from the FAD2A gene using real-time PCR and classified into three genotypes with significantly different O/L ratios: wild type (G/G with a low O/L ratio <1.7), heterozygote (G/A with O/L ratio >1.4 but <1.7), and mutant (A/A with a high O/L ratio >1.7). The results from real-time PCR genotyping and GC fatty acid analysis were consistent. Accessions with high amounts of oil, quercetin, high seed weight, and O/L ratio were identified. The results from this study may be useful not only for peanut breeders, food processors, and product consumers to select suitable accessions or cultivars but also for curators to potentially expand the mini-core collection. © 2013 American Chemical Society.

Harris-Shultz K.,Crop Genetics and Breeding Research Unit | Raymer P.,University of Georgia | Scheffler B.E.,U.S. Department of Agriculture | Arias R.S.,U.S. Department of Agriculture
Crop Science | Year: 2013

The increasing use of secondary water sources for irrigation, which is highly linked to salinization, creates a demand for salt tolerant turf. Seashore paspalum (Paspalum vaginatum Swartz) is a warm-season turfgrass that survives in sand dunes along coastal sites, brackish ponds, and in estuaries. Some seashore paspalum accessions and cultivars are far more salt tolerant than others. To identify genetic regions that are associated with salt tolerance, molecular tools must be developed. In this study, genomic libraries, enriched for microsatellites, were generated using the salt tolerant accession HI33. High throughput sequencing and subsequent assembling of these libraries resulted in 18,967 contigs and 158,595 singletons. The number of simple sequence repeats (SSR) detected in contigs and in singletons was 3511 and 31,949, respectively, and the number of primer sets designed within each group was 937 and 1667. A total of 80 SSR markers, including five markers previously developed, were used to assess genetic relationships among 18 Paspalum accessions. Two major clusters were identified from the seashore paspalum accessions. Accessions that are likely polyploids, all with coarse leaves, grouped together whereas accessions with fine-to mid-fine leaves formed a second group. Furthermore, 33 seashore paspalum SSR markers cross-amplified in bahiagrass (Paspalum notatum Flugge) and these markers can be a useful tool in this species. © Crop Science Society of America.

Yang L.,Huaiyin Normal University | Yang L.,University of Georgia | Yang L.,Crop Protection and Management Research Unit | Ji J.,Huaiyin Normal University | And 6 more authors.
Frontiers in Plant Science | Year: 2016

The heavy metal cadmium is a common environmental contaminant in soils and has adverse effects on crop growth and development. The signaling processes in plants that initiate cellular responses to environmental stress have been shown to be located in the plasma membrane (PM). A better understanding of the PM proteome in response to environmental stress might provide new insights for improving stress-tolerant crops. Nitric oxide (NO) is reported to be involved in the plant response to cadmium (Cd) stress. To further investigate how NO modulates protein changes in the plasma membrane during Cd stress, a quantitative proteomics approach based on isobaric tags for relative and absolute quantification (iTRAQ) was used to identify differentially regulated proteins from the rice plasma membrane after Cd or Cd and NO treatment. Sixty-six differentially expressed proteins were identified, of which, many function as transporters, ATPases, kinases, metabolic enzymes, phosphatases, and phospholipases. Among these, the abundance of phospholipase D (PLD) was altered substantially after the treatment of Cd or Cd and NO. Transient expression of the PLD fused with green fluorescent peptide (GFP) in rice protoplasts showed that the Cd and NO treatment promoted the accumulation of PLD in the plasma membrane. Addition of NO also enhanced Cd-induced PLD activity and the accumulation of phosphatidic acid (PA) produced through PLD activity. Meanwhile, NO elevated the activities of antioxidant enzymes and caused the accumulation of glutathione, both which function to reduce Cd-induced H2O2 accumulation. Taken together, we suggest that NO signaling is associated with the accumulation of antioxidant enzymes, glutathione and PA which increases cadmium tolerance in rice via the antioxidant defense system. © 2016, Yang, Ji, Harris-Shultz, Wang, Wang, Abd-Allah, Luo and Hu.

Yang L.,Huaiyin Normal University | Yang L.,Crop Protection and Management Research Unit | Yang L.,University of Georgia | Ji J.,Huaiyin Normal University | And 6 more authors.
Frontiers in Plant Science | Year: 2016

To clarify the roles of carbon monoxide (CO), nitric oxide (NO), and auxin in the plant response to iron deficiency (–Fe), and to establish how the signaling molecules interact to enhance Fe acquisition, we conducted physiological, genetic, and molecular analyses that compared the responses of variousArabidopsis mutants, including hy1(CO deficient), noa1 (NO deficient), nia1/nia2 (NO deficient), yuc1 (auxin over-accumulation), and cue1 (NO over-accumulation) to –Fe stress. We also generated a HY1 over-expression line (named HY1-OX) in which CO is over-produced compared to wild-type. We found that the suppression of CO and NO generation using various inhibitors enhanced the sensitivity of wild-type plants to Fe depletion. Similarly, the hy1, noa1, and nia1/nia2 mutants were more sensitive to Fe deficiency. By contrast, the yuc1,cue1, and HY1-OX lines were less sensitive to Fe depletion. The hy1 mutant with low CO content exhibited no induced expression of the Fe uptake-related genes FIT1 and FRO2 as compared to wild-type plants. On the other hand, the treatments of exogenous CO and NO enhanced Fe uptake. Likewise, cue1 and HY1-OX lines with increased endogenous content of NO and CO, respectively, also exhibited enhanced Fe uptake and increased expression of bHLH transcriptional factor FIT1as compared to wild-type plants. Furthermore, we found that CO affected auxin accumulation and transport in the root tip by altering the PIN1 and PIN2 proteins distribution that control lateral root structure under –Fe stress. Our results demonstrated the integration of CO, NO, and auxin signaling to cope with Fe deficiency in Arabidopsis. © 2016 Yang, Ji, Wang, Harris-Shultz, Abd_Allah, Luo, Guan and Hu.

Scully B.T.,Crop Protection and Management Research Unit | Scully B.T.,U.S. Department of Agriculture | Krakowsky M.D.,North Carolina State University | Ni X.,Crop Genetics and Breeding Research Unit | And 4 more authors.
Journal of Plant Registrations | Year: 2016

Maize (Zea mays L.) inbred line GT888 (PL-364, PI 670116) was developed and released by the USDA-ARS in cooperation with the University of Georgia and in participation with the USDA Germplasm Enhancement of Maize (GEM) project. GT888 was derived from GEM population DK888:N11 (GEMN-0177), which has 50% tropical and 50% temperate parentage. GT888 is a yellow dent inbred that was selected through a pedigree breeding program for improved resistance to aflatoxin contamination produced by the causal organism Aspergillus flavus (Link: Fr.). It was compared with three inbreds, Mp313E, Mp717, and Mp719, which are known standards that resist aflatoxin contamination. GT888 also exhibits heterosis when crossed to stiff stalk testers B14, B73, and LH132 and was assigned to the non-stiff stalk group. GT888 tasseled and silked approximately 5 to 8 d later than a cohort of non-stiff stalk standards. © 2015 Crop Science Society of America. All rights reserved.

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