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ALARC Highlights Spring 2014
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Featured Recent Accomplishment

Production of high amounts of oil in the leaves of plants

Our society is heavily dependent on crude oil to support our way of life. Crude oil, also known as c components of manufacturing. As such, just about everything that we use on a daily basis can be traced back in one way or another to crude oil. But in light of increased worldwide demand, decreasing production, and increased environmental concerns, it is imperative that we develop alternative sources of fuel and chemical feedstocks.

Plant oils show outstanding potential as replacements for petroleum because the fatty acid components of plant oils are chemically similar to the long chain hydrocarbons of fossil oils. The primary challenge in using plant oils for these purposes, however, is one of economy of scale, because the demand for transport fuels is far greater than what agriculture can typically deliver.

To help address this problem, scientists at the ARS lab in Maricopa, Arizona, in collaboration with scientists at the University of Guelph and University of North Texas, are exploring novel approaches for massively increasing the amount of oil that can be recovered from plants. Rather than focusing exclusively on increasing the oil content in plant seeds, which is the typical source for plant oils, the scientists are also focused on increasing oil content in plant leaves and stems. The rationale for this is simple; the leaves and stems of a plant dominate plant biomass, while the seeds are just a minor component. Thus, production of even modest amounts of oil in vegetative tissues could significantly increase the amount of oil recovered.


Figure 1. Microscopic, 3-dimensional images of plant leaves showing oil accumulation. The images were generated using a confocal microscope and are oriented to look Arabidopsis leaf and the bottom panel shows a portion of a leaf from a plant that is over-expressing a gene that promotes oil accumulation. Image provided by Dr. Kent Chapman at UNT.

The scientists are exploring a variety of approaches to increase oil content in leaves, including up-regulation of genes involved in oil synthesis, down-regulation of genes involved in oil degradation, and over-expression of genes involved in compartmentalization or "storage" of oil in plants.  Results to date have shown that plants can be dramatically altered, resulting in massive changes in oil content in leaves (Figure 1).

While studies to date have been conducted in the model plant Arabidopsis, engineering oil accumulation in rapidly growing perennial grasses such as Miscanthus or switchgrass could result in development of dedicated, biomass/biofuel non-food crops capable of growing on traditionally non-productive, degraded, or marginal lands. Achieving this goal could allow us to more sustainably "live off the fat of the land". Furthermore, some plants engineered in this study showed enhanced seed oil content, indicating that knowledge gained from these studies can also be used to enhance oil content in more traditional oilseed crops. (Contact:

Other Recent Accomplishments

An adult transcriptome for Lygus bug. The western tarnished plant bug (Lygus hesperus) is an important crop pest in the western United States for which almost no molecular genetics information exists. ARS scientists from Maricopa, Arizona, used next-generation sequencing to construct an adult Lygus transcriptome, which represents a record of gene expression. Compared with better-studied insects, many of the sequences were unique to Lygus. Intriguingly, compared with other insects a higher percentage of sequences were associated with antioxidant activity, which may be important to resisting biotic and abiotic stress. Exposure to high temperatures triggered increased expression of heat shock proteins that are thought to facilitate short-term adaptation to environmental stresses. This information serves as a broad baseline for future research, and will be essential to efforts to identify and develop new species-specific non-insecticidal controls. (Contact:

Identification of Lygus bug sex pheromones. Lygus bugs (western tarnished plant bug, tarnished plant bug, and the pale legume bug) are important pests of many field, fruit, and vegetable crops. Elucidation of the chemicals emitted by females to attract males for mating (sex pheromones) has represented an intractable problem. An ARS scientist in Maricopa, Arizona, and Israeli collaborators identified the chemical components of the respective Lygus sex pheromones and demonstrated attractiveness to males in field studies. These results provide the opportunity to develop pheromone lures and traps to permit improved population detection and monitoring. (Contact:

Thermal ecology of Lygus bug. Because the adult reproductive diapause of Lygus in southern regions terminates in early winter, development and survival of immature stages and young adults under winter conditions may be as important to successful overwintering as the diapause. ARS scientists from Maricopa, Arizona, and Wapato, Washington, defined the temperature dependence of development and survival for all Lygus life stages. Research demonstrated extended development times and host-free survival under low-temperature conditions. Ecological interpretation of these results is consistent with field observations of overwintering populations, and quantitative models permit prediction of population phenology given appropriate meteorological inputs. These results important to a more complete understanding of Lygus overwintering ecology, and provide important baseline information for ongoing examinations of the physiology and molecular biology of Lygus thermal ecology. (Contact:

Comparison of temperature response functions used in crop models. A recurring question in crop physiology is how best to describe the effects of temperature on specific processes such as the formation of leaves. Scientists in Maricopa, Arizona, compared five widely used models for temperature using data from the Hot Serial Cereal field experiment, which included 15 planting dates, six of which had temperature free-air controlled enhancement (T-FACE) treatments to further extend the temperature regimes. Results showed that for the cultivar tested, leaf appearance reaches a maximum rate at about 22 C, and that even our extensive dataset was insufficient to determine whether higher temperatures might slow leaf appearance, as is often assumed. These results emphasize the need for caution in interpreting modeled responses of wheat to elevated temperatures. They should contribute to more accurate assessments of impacts of climate change, ultimately allowing for more robust decisions on climate change policy. (Contact:

Genome analysis of guayule. Guayule is a woody, desert shrub under development as a domestic source of natural rubber, but improving rubber yields will require a better understanding of the genes involved in regulating rubber synthesis. Scientists in Maricopa, Arizona, completed an analysis of genome size, chromosome number, and ploidy on 36 Parthenium (guayule) species and their interspecific hybrids. Wide variation in genomes was observed, with genome size ranging from 1,624 Mb in diploids to 5,756 Mb in tetraploids, and interspecific hybrids ranging from 2,523 to 4,225 Mb. The results of these studies will be useful for genetic and genome-wide population analysis, with the end-goal of identifying genomic markers or individual genes that can be used to improve rubber yields. (Contact:

Elucidation of a new strategy for enhancing photosynthetic performance. In the process of photosynthesis, plants convert light into chemical energy. The energy produced by photosynthesis is then used to synthesize the carbon compounds that are harvested for food, fuel, fiber or other natural products. Consequently, photosynthesis determines the overall yield of the plant. Scientists in Maricopa, Arizona, uncovered important new information about the control of Rubisco, the rate-determining enzyme in photosynthesis, by its regulatory companion, Rubisco activase. The research showed that changes in the regulatory properties of Rubisco activase affected the rate at which photosynthesis turned on when light was increased. These findings suggest a new strategy for increasing photosynthetic performance in certain variable light environments based on altering the regulatory properties of Rubisco activase.

Quantifying cropland evapotranspiration (ET) with remote sensing images. Quantifying the water used by crops over time and space is critical for managing scarce water supplies. Two well-known competing remote sensing ET models were evaluated for consistency and ease-of-use by scientists in Maricopa, Arizona, using experimental data collected for cotton crops. The models, Two Source Energy Balance (TSEB) and Mapping Evapotranspiration at high Resolution and with Internalized Calibration (METRIC) were implemented and found to return ET estimates consistent to within 1.5 mm/day. The evaluation study highlighted the benefits for having multiple models available to map ET. The TSEB approach is preferred when input data are accurate because it can be applied anywhere with less reliance on site-specific calibrations and the METRIC approach is preferred when inputs are less certain and when implementation simplicity is important. Outcomes from this research will help research scientists at US Department of Agriculture, US Geological Survey, and US Bureau of Reclamation, develop a suite of tools to map and manage scarce water needed for irrigated agriculture in the United States. (Contact:

Sorption of the antibiotic lincomycin to arid regions soils. The reuse of sewage effluent for irrigation is an effective way to increase water supplies in the desert southwest. Contaminants such as antibiotics, found in treated effluent, have been identified as a potential problem for use of this water for irrigation. Scientists in Maricopa, Arizona, determined environmental fate parameters for lincomycin using three arid region soils. Lincomycin sorption is related to soil pH. When soil pH is below 7.6, lincomycin exhibits little sorption to soil, however, when soil pH is above 7.6 sorption of lincomycin is increased 10 fold. These results can be used to determine site-specific guidelines for disposal and use of reclaimed water. (Contact:

ALARC Recent Research in the News

The genetic basis of evolved resistance to GMO cotton in India. Science 2.0, Meridian Institute,,, and Agrimarketing on May 19, 2014 reported on research led by ARS scientist Jeffrey Fabrick at Maricopa, Arizona, on the molecular basis of insect resistance to genetically modified cotton plants. Link

Deciding when to spray: Sometimes its more than just numbers. ARS scientists Dale Spurgeon and Rodney Cooper explore how the growth stage of the cotton plant and the stage of the pest plant bug, Lygus hesperus, can influence the decision to apply an insecticide. Link

Diverse approaches to tame an emerging pest. ARS scientists Colin Brent, Joe Hull and Dale Spurgeon examine how the basic biology of Western tarnished plant bug (Lygus hesperus) allows it to thrive in hot environments. Link

Recent Journal Publications


Brent CS, Klok CJ, Naranjo SE. 2013. Effect of diapause status and gender on activity, metabolism and starvation resistance in the plant bug Lygus hesperus Knight. Entomologia Experimentalis et Applicata 148:152-160 (PDF)

Byers JA, Fefer D, Levi-Zada A. 2013. Sex pheromone component ratios and mating isolation among three lygus plant-bug species of North America. Naturwissenschaften 100:1115-1123. (PDF)

Byers JA 2013. Modeling and regression analysis of semiochemical dose-response curves of insect antennal reception and behavior. Journal of Chemical Ecology 39:1081-1089. (PDF)

Castle SJ, Prabhaker N. 2013. Monitoring changes in Bemisia tabaci susceptibility to neonicotinoid insecticides in Arizona and California. Journal of Economic Entomology 106:1404-1413. (PDF)

Fabrick JA, Pei J, Hull JJ, Yool AJ. 2014. Molecular and functional characterization of multiple aquaporin water channel proteins from the western tarnished plant bug, Lygus hesperus. Insect Biochemistry and Molecular Biology 45:125-140. (PDF)

Hull JJ, Perera OP, Snodgrass GL. 2014. Cloning and expression profiling of odorant-binding proteins in the tarnished plant bug, Lygus lineolaris. Insect Molecular Biology. 23:78-97. (PDF)

Hull JJ, Matsumoto S. 2013. Molecular mechanisms underlying insect behaviors: receptors, peptides, & biosynthetic pathways. Frontiers in Endocrinology 4:120. doi: 10.3389/fendo.201300120. (PDF)

Kelly JL, Hagler JR, Kaplan I. 2014. Semiochemical lures reduce emigration and enhance pest control services in open-field predator augmentation. Biological Control 71:70-77. (PDF)

Luo S, Naranjo SE, Wu K 2013. Biological control of cotton pests in China. Biological Control 68:6-14. (PDF)

Naranjo SE. 2013. Effects of Bt crops on arthropod natural enemies: A global synthesis. pp. 288-291 in Proceedings of the 4th International Symposium on Biological Control of Arthropods, Puc (PDF)

Swezey SL, Nieto DJ, Pickett CH, Hagler JR, Bryer JA, Machtley SA. 2014. Dispersion and movement of the Lygus spp.parasitoid Peristenus relictus (Hymenoptera: Braconidae) in trapcropped organic strawberries. Environmental Entomology 42:770-778. (PDF)

Tabashnik BE, Fabrick JA, Unnithan GC, Yelich AJ, Masson L, Zhang J, Bravo A, Soberon M. 2013. Efficacy of genetically modified Bt toxins alone and in combinations against pink bollworm resistant to Cry1Ac and Cry2Ab. PLoS One 8:e80496. (PDF)

Tian JC, Long LP, Wang XP, Naranjo SE, Romeis J, Hellmich RL, Wang P, Shelton AM. 2014. Using resistant prey demonstrates that Bt plants producing Cry1Ac, Cry2Ab and Cry1F have no negative effects on Geocoris punctipes and Orius insidiosus. Environmental Entomology 43:242-251. (PDF)

Zilnik G, Hagler JR. 2013. An immunological approach to distinguish arthropod viviphagy from necrophagy. Biocontrol 58:807-814. (PDF)

Plant Science

Andrade-Sanchez P, Gore M, Heun J, Thorp KR, Carmo-Silva E, French AN, Salvucci ME, White JW. 2013. Development and evaluation of a field-based high-throughput phenotyping platform. Functional Plant Biology 41:68-79. (PDF)

Gaihre YK, Wassman R, Tirol-Padrea A, Villegas-Pangga G, Aquino E, Kimball BA. 2013. Seasonal assessment of greenhouse gas emission from irrigated lowland rice field under infrared warming. Agriculture, Ecosystems and Environment 18:88-100. (PDF)

Hassan M, Qayyum A, Razzaq A, Ahmad M, Mahmood I, Ullah Khan S, Bibi Y, Jenks MA. 2013. Evaluation of maize cultivars for drought tolerance based on physiological traits associated with cell wall plasticity. Wulfenia Journal 63:466-478.

Horn PJ, James CN, Gidda SK, Kilaru A, Dyer JM, Mullen RT, Ohlrogge JB, Chapman KD. 2013. Identification of a new class of lipid droplet-associated proteins in plants. Plant Physiology 162:1926-1936. (PDF)

Lager I, Yilmaz JL, Zhou XR, Jasieniecka K, Kazachkov M, Wang P, Zou J, Weselake R, Smith MA, Bayon S, Dyer JM, Shockey JM, Heinz E, Green A, Banas A, Stymne S. 2013. Plant acyl-CoA:lysophosphatidylcholine acyltransferases (LPCATs) have different specificities in their forward and reverse reactions. Journal of Biological Chemistry 288:36902-14.

Ottman MJ, Hunt LA, White JW. 2013. Photoperiod and vernalization effect on anthesis date in winter-sown spring wheat regions. Agronomy Journal 105:1017-1025. (PDF)

Park S, Gidda SK, James CN, Horn PJ, Khuu N, Seay DC, Keereetaweep J, Chapman KD, Mullen RT, Dyer JM. 2013. The alpha/beta hydrolase CGI-58 and peroxisomal transport protein PXA1 coregulate lipid homeostasis and signaling in Arabidopsis. Plant Cell 25:1726-1739. (PDF)

Park S, Keereetaweep J, James C, Gidda SK, Chapman KD, Mullen RT, Dyer JM. 2014. CGI-58, a key regulator of lipid homeostasis and signaling in plants, also regulates polyamine metabolism. Plant Signaling & Behavior 9:e27723;

Sanchez PL, Chen M, Pessarakli M, Hill H, Gore MA, Jenks MA. 2014. Effects of temperature and salinity on germination of non-pelleted and pelleted guayule (Parthenium argentatum A. Gray) seeds. Industrial Crops and Products 55:90-96. (PDF)

Sanchez PL, Costich D, Friebe B, Coffelt TA, Jenks MA, Gore MA. 2014. Genome size variation in guayule and mariola: Fundamental descriptors for polyploid plant taxa. Industrial Crops and Products 54: 1-5. (PDF)

Wall GW, Mclain JE, Kimball BA, White JW, Ottman MJ, Garcia RL. 2013. Infrared warming affects intrarow soil carbon dioxide efflux during early vegetative growth of spring wheat. Agronomy Journal 105:607-618. (PDF)

White JW, Conley MM. 2013. A flexible, low-cost cart for proximal sensing. Crop Science 53:1646-1649. (PDF)

Water Conservation

Mclain JE, Williams CF. 2014. Sustainability of water reclamation: long-term recharge with reclaimed wastewater does not enhance antibiotic resistance in sediment bacteria. Sustainability 6:1313-1327. (PDF)

Thorp K., Ale S, Bange MP, Barnes EM, Hoogenboom G, Lascano JR, McCarthy AC, Nair S, Paz JO, Rajan N, Reddy KR, Wall GW, White JW. 2014. Development and application of process-based simulation models for cotton production: A review of past, present, and future directions. Journal of Cotton Science 18:10 (PDF)

Thorp K, Bronson K. 2013. A model-independent open-source geospatial tool for managing point-based environmental model simulations at multiple spatial locations. Environmental Modelling & Software 50:25-36. (PDF)

Wang G, Bronson KF, Thorp KR, Mon J, Badaruddin M. 2014. Multiple leaf measurements improve effectiveness of the cholorophyll meter in drum wheat nitrogen management Crop Science 54:817 (PDF)

Williams CF, Watson JE, Nelson SD. 2014. Comparison of equilibrium and non-equilibrium distribution coefficients for the human drug carbamazepine in soil. Chemosphere 95:166-173. (PDF)

Williams, CF, Watson JE, Nelson SD, Walker CW. 2013. Sorption/Desorption of lincomycin from three arid region soils. Journal of Environmental Quality 42:1460-1465. (PDF)

Current Grant Awards (*new)

*Selecting and Using Bt-Resistant Strains of Two Key Pests to Understand Resistance and Characterize Responses to Novel Toxins, CRADA Pioneer Hi-Bred International (PI Jeff Fabrick) 2013-2016.

*Identification of Factors Mediating Environmental Acclimation in Lygus hesperus, Cotton Incorporated (PIs Colin Brent Joe Hull, Jeff Fabrick) 2014-2015.

*The Integrated Program to Accelerate Breeding of Resilient, more Productive Plans for Smallholder Farmers, Pennsylvania State University (PI Jeff White) 2014-2015.

Evaluation of the Cropgro-Cotton Model for Arizona Cotton Production Systems, Cotton Incorporated (PI Kelly Thorp) 2013-2014.

Use of Agrotain in Improving Nitrogen Fertilizer Management in Surface-Irrigated Cotton, Koch Agronomic Services, LLC (PI Kevin Bronson) 2013-2014.

Applying Proximal Sensing to Enhance Upland Cotton Yield Trials, Cotton Incorporated (PI Andy French) 2013-2014.

Role of Omega-3 Fatty Acid Desaturase Genes in Cold Temperature Tolerance of Cotton, Cotton Incorporated (PI John Dyer) 2012-2015.

Evaluating and Predicting H2O Consumption by Irrigated Agriculture in Israel and US: Inverse Biophysical Modeling Utilizing Spaceborne Imagery, Binational Agricultural Research and Development Fund (BARD) (PI Andy French) 2012-2015.

Accelerated Development of Commercial Hydrotreated Renewable Jet (HRJ) Fuel from Redesigned Oil Seed Feedstock Supply Chains, USDA-NIFA/DOE Biomass Research and Development Initiative (PI T. Isbell, Co-PIs John Dyer, Mike Gore, D. Long, D. Archer, S. Frey, D. Galloway, T. Tomlinson) 2012-2016.

Securing the Future of Natural Rubber Colvin, Co-PIs Mike Gore, C. McMahan, John Dyer, A. Halog, J. Mitchell, P. Zorner, Collaborator, Doug Hunsaker) 2012-2016.

Managing Pierce's Disease in Arizona Vineyards, USDA Specialty Crop Block Grant Program (PI Steve Castle) 2012-2014.

High-Throughput Phenotyping Using Portable LIDAR, Cotton Incorporated (PI Andy French with Co-PIs M. Gore, Cornell University and P. Andrade-Sanchez, University of Arizona) 2012-2014.

Impact of Bioenergy Crops on Pests, Natural Enemies and Pollinators in Agricultural and Non-Crop Landscapes, USDA-NIFA-AFRI (Co-PI James Hagler with T. Kring and R. Weidenman, University of Arkansas; B. McCornack, Kansas State University; K. Giles, Oklahoma State University) 2011-2016

Investigation into Effects of Soil Moisture Depletion on Vegetable Crop Uptake of Microcontaminants under Recycled Water Irrigation, USDA-NIFA-AFRI (PI Clinton Williams with C. Ray, University of Hawaii) 2011-2014

Improving Nitrogen Fertilizer Management and Fate of Nitrogen in Surface Irrigated Cotton, Cotton Incorporated (PI Kevin Bronson) 2011-2014

Ecological and Agricultural Productivity Forecasting Using Root-Zone Soil Moisture Products Derived from the NASA SMAP Mission, NASA (Co-PI Kelly Thorp with W. Crow, USDA-ARS Beltsville [PI]; S. Moran, USDA-ARS Tucson; G. Nearing, University of Arizona; R. Reichle NASA) 2010-2014

Recent Professional Awards

Kevin Bronson was named a Fellow of the Soil Science Society of America (SSSA) in 2013. The status of Fellow recognizes those who have made significant contributions to the SSSA and science.

Steve Naranjo and team members received the 2013 IPM Team Award sponsored by the Entomological Foundation and DOW AgroSciences. The Team was honored for their contribution to significantly enhancing environmental risk assessment of beneficial non-target arthropods in genetically modified Bt crops through research, outreach and implementation. The Team includes members from Agroscope-Switzerland, Cornell University, USDA-ARS, Center for Environmental Risk Assessment, Syngenta-UK, Innovative Environmental Services-Switzerland, Purdue University and Pioneer Hi-Bred.

Jeff White received an Outstanding Reviewer Award for Environmental Modelling and Software in 2013. The award recognizes the high quality reviews provided to the journal.

Recent Events and Outreach

  • In June and July 2013, scientists and technicians from USDA-ARS, Maricopa, AZ mentored six high school students and one teacher through a USDA-NIFA A-UBET grant to South Mountain Community College (HSI). Students completed projects and presented their findings during a poster/luncheon session in July. Many students expressed an interest in pursuing degrees in biology and engineering and returning to the Center for additional training and experience in the future. Fifteen high school students will be doing internships at the Center during the summer of 2014.

  • On March 13, 2014, Scientists and post-doctoral visited the Ira Hays High School on the Gila River Indian Community. They visited a science class, an art class, and participated in a special assembly of the whole school and all teachers. At the assembly Center scientists spoke, about their research areas and about careers in agriculture, natural resources and working for the USDA.

  • On March 13, 2014, employees of Blue River Technology, a Mountain View, CA technology company visited the USDA-ARS Center in Maricopa, AZ to exchange information about plant-scale image analysis in agriculture. They are interested in supporting uture cooperation could involve field-testing their equipment in our experiments plots.

  • On May 8, 2014, the USDA-ARS Center in Maricopa, AZ celebrated Asian-Pacific American Heritage Month with a festive Hawaiian luncheon. The event featured Hawaiian music and slide show and an authentic Hawaiian greeting from Pualani Hockenhull, a native of Maui now living in the Phoenix area.