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Characterization of three transcripts encoding small heat shock proteins expressed in the codling moth, Cydia pomonella （Lepidoptera： Tortricidae）

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Insect Science 2011年第5期18卷 473-483页

作者： Stephen F. Garczynski Thomas R. Unruh Christelle Guedot Lisa G. Neven usda-ars Yakima Agricultural Research Laboratory Wapato Washington USA

Codling moth is a major pest of apples and pears worldwide. Increasing knowledge of how this insect responds to environmental stress will improve field and postharvest control measures used against it. The small heat shock proteins （sHsps） play a maj or role in cellular responses to environmental stressors. A degenerate oligonucleotide primer, designed against the conserved α-crystallin domain, was used in 3＇ rapid amplification of complementary DNA （cDNA） ends reactions to amplify transcripts encoding sHsps expressed in the codling moth cell line, Cp169, subjected to heat shock. Three full-length cDNAs were cloned from Cp169 cells that contained open reading frames encoding sHsps. The cDNA for CpHsp 19.8 was 795 bp encoding 177 amino acids. The cDNA for CpHsp 19.9 was 749 bp encoding 175 amino acids. The cDNA for CpHsp22.2 was 737 bp encoding 192 amino acids. Analysis of the protein sequences of the three CpHsps indicated the presence of 83 amino acids with homology to the α-crystallin domain. For each of the CpHsps, the α-crystallin domain was surrounded by divergent N- and C-terminal regions, consistent with the conserved structural features of sHsps. Real-time polymerase chain reaction, used to determine the expression patterns of each of the sHsps in different developmental stages of codling moth revealed the presence of transcripts in all stages tested. Consistent with characteristics of other sHsps, expression of CpHsp transcripts were greatly enhanced when insects were subjected to heat shock. The results of this research can be used as a guide to study the roles of sHsps in codling moth control using various post-harvest treatments.

关键词： α-crystallin domain heat shock response qPCR

The evolution of Hessian fly from the Old World to the New World： Evidence from molecular markers

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Insect Science 2015年第6期22卷 768-784页

作者： Brandon J. Schemerhom Yan Ma Crane Charles F. Crane usda-ars Department of Entomology Department of Botany and Plant Pathology Purdue University West Lafayette IN 47907USA

Eighteen polymorphic microsatellite loci and 11 single-nucleotide polymor- phisms were genotyped in 1 095 individual Hessian fly specimens representing 23 popula- tions from North America, southern Europe, and southwest Asia. The genotypes were used to assess genetic diversity and interrelationship of Hessian fly populations. While phyloge- netic analysis indicates that the American populations most similar to Eurasian populations come from the east coast of the United States, genetic distance is least between （Alabama and California） and （Kazakhstan and Spain）. Allelic diversity and frequency vary across North America, but they are not correlated with distance from the historically documented point of introduction in New York City or with temperature or precipitation. Instead, the greatest allelic diversity mostly occurs in areas with Mediterranean climates. The mi- crosatellite data indicate a general deficiency for heterozygotes in Hessian fly. The North American population structure is consistent with multiple introductions, isolation by dis- tance, and human-abetted dispersal by bulk transport of puparia in infested straw or on harvesting equipment.

关键词： allele frequency Hessian fly microsatellite population structure SNP SSR

Evaluation of maize inbred lines and topcross progeny for resistance to pre-harvest aflatoxin contamination

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The Crop Journal 2019年第1期7卷 118-125页

作者： Jake C.Fountain Hamed K.Abbas Brian T.Scully Hong Li Robert D.Lee Robert C.Kemerait Baozhu Guo usda-ars Crop Protection and Management Research Unit Department of Plant Pathology University of Georgia usda-ars Biological Control of Pests Research Unit usda-ars National Horticultural Research Laboratory Shanxi Academy of Agricultural Sciences Millet Research Institute Department of Crop and Soil Sciences University of Georgia

Pre-harvest aflatoxin contamination occurs in maize following kernel colonization by Aspergillus flavus. Aflatoxin contamination resistance is a highly desired trait in maize breeding programs.The identification of novel sources of resistance to pre-harvest aflatoxin contamination is a major focus in germplasm screening efforts. Here, we performed a field evaluation of 64 inbred lines over two years for pre-harvest aflatoxin contamination. Topcrosses were also performed with two testers, B73 and Mo17, to generate 128 F1 hybrids which were also evaluated over two years. Hybrid performance was used to calculate both general combining ability(GCA) of the inbreds, and observed heterosis for aflatoxin resistance. Over both years of the study, aflatoxin concentrations ranged from 80 ± 47 to 17,617 ± 8816 μg kg^(-1) for inbreds, and from 58 ± 39 to 2771 ± 780 μg kg^(-1) for hybrids with significant variation between years and lines. The inbred lines CML52, CML69, CML247, GT-603, GEMS-0005, Hi63, Hp301, and M37 W showed ars of the study and less than the resistant check, Mp313 E, in at least one season. Among these, CML52, GT-603, and Hi63 also showed significant GCA with the testers in hybrid progeny. CML52, GT-603, and M37 W also showed heterotic effects of-13.64%,-12.47%, and-24.50%, respectively, with B73 resulting in reduced aflatoxin contamination. GT-603 also showed a similar heterotic effect for aflatoxin contamination,-13.11%, with Mo17 indicating that this line may serve as a versatile source of aflatoxin contamination resistance in breeding programs.

关键词： Aspergillus flavus Pre-harvest Aflatoxin Maize Topcross

Root Plate Growth in Sunflower and Its Relevance to Sclerotinia Basal Stalk Rot

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American Journal of Plant Sciences 2022年第3期13卷 359-370页

作者： Christopher G. Misar Northern Crop Science Laboratory USDA-ARS Fargo ND USA

Sclerotinia basal stalk rot (BSR) of sunflower (Helianthus annuus L.) is a fungal disease of the roots that causes symptoms of wilt and a basal stem lesion. Evaluating root plate growth could improve our understanding of BSR. Separate studies were conducted to determine the effect of sunflower growth stage or genotype on root plate diameter in North American environments. Root plate diameter of cultivated hybrids at reproductive growth stages was 3 to 4 times larger than vegetative stages. Cultivated hybrids had larger root plate diameter than interspecific lines. These results have implications for artificial inoculation methods that evaluate genotypes for BSR resistance in the field or greenhouse. Disease escapes can occur if field-grown plants are inoculated too far from the root plate and/or too early at vegetative growth stages. Side-dressing mycelium-infested cereal grain closer (i.e., 10 cm) to plants at reproductive growth stages (i.e., R1 - R4) can increase disease pressure and reduce disease escapes. These guidelines for the field can be used to validate results from artificial inoculations in the greenhouse.

关键词： Canopy Closure Inoculation Method Root Plate Diameter Sclerotinia Wilt

Annual Rainfall and Dryland Cotton Lint Yield—Southern High Plains of Texas

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Agricultural Sciences 2022年第2期13卷 177-200页

作者： Robert J. Lascano Paxton Payton James R. Mahan Timothy S. Goebel Dennis C. Gitz III Wind Erosion and Water Conservation Research Unit USDA-ARS Lubbock TX USA Plant Stress and Germplasm Development Research Unit USDA-ARS Lubbock TX USA

Agriculture in the Texas High Plains (THP) is in a transition phase of producing crops with a diminishing supply of irrigation-water from the Ogallala aquifer to dryland production systems. This shift is driven by the fact that the depth to the water table of the Ogallala aquifer continues to increase. Dryland cotton production systems are prevalent in the southern counties of the THP and our purpose was to use the long-term dryland cotton lint yields from these counties as precursors of the future cotton production patterns that will emerge in this region. For this purpose, from 1972 to 2018, we calculated the ratio of dryland cotton lint yield per unit of annual rainfall at the county level. This ratio is called crop water productivity (CWP) and has units of mass per unit volume (g/m3). In our analysis, we used cotton lint yield data provided by the National Agricultural Statistics and rainfall data provided by the National Oceanic and Atmospheric Administration. Our results indicated that the three datasets used in our analysis, i.e., cotton lint yield, rainfall and CWP were all normally distributed. In this time period, 1972 to 2018, only one year 2011—a year with a record drought of 179 mm of rain failed to produce a dryland cotton crop in all the counties used in our analysis. The mean cotton lint yield ± standard deviation ranged from a high of 400 ± 175 kg/ha in Lubbock County to a low of 252 ± 144 kg/ha in Andrews County. However, the counties with the largest CWP > 90 g/m3 were Glasscock, Midland and Martin County. The importance of this result is that these counties are in the southern region of the THP and are subject to extreme environmental conditions and yet cotton producers manage to produce a cotton crop in most years. We conclude that management production methods used by these dryland producers represent the future schemes that will need to be adopted in other counties to sustain the emerging dryland cropping systems across the THP.

关键词： Crop Water Productivity Cotton Cropping Systems Crop Management Rainfed Ogallala Aquifer Water Use Efficiency

Stability and transferability assessment of the cotton fiber strength QTL qFS-c7-1 on chromosome A07

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The Crop Journal 2021年第2期9卷 380-386页

作者： David D.Fang Linghe Zeng Gregory N.Thyssen Christopher D.Delhom Efrem Bechere Don C.Jones Ping Li Cotton Fiber Bioscience Research Unit USDA-ARS-SRRCNew OrleansLA 70124USA Crop Genetics Research Unit USDA-ARSStonevilleMS 38776USA Cotton Chemistry&Utilization Unit USDA-ARS-SRRCNew OrleansLA 70124USA Cotton Structure and Quality Research Unit USDA-ARS-SRRCNew OrleansLA 70124USA Cotton Incorporated CaryNC 27513USA

Previously we identified a major cotton fiber strength QTL(qFS-c7-1)on chromosome A07 using a multiparent advanced generation intercross(MAGIC)population.To assess the stability and transferability of this QTL and its utility in cotton breeding,we made ten new populations.These populations were developed from crosses between MAGIC recombinant inbred lines,or between cotton cultivars that are different from the MAGIC parents.A total of 2801 F_(2) plants were grown and their fiber quality traits were measured.We also selected a subset of F_(3) seeds from two populations,and grew F_(3) progeny plots to further evaluate the stability of this QTL.Our results showed that the peak of qFS-c7-1 is at 70–72 Mb region.This QTL had a major effect on fiber strength explaining 21.9%phenotypic variance.Its effect on other fiber quality attributes such as micronaire,short fiber content,length and uniformity varied between populations,and no effect on fiber elongation was observed.The QTL effects were stable in the populations analyzed,and in different generations of the same population.The SSR and SNP markers near and within the QTL peak reported herein will assist selecting superior fiber quality traits in breeding,with a recommendation that the parental cotton lines should be analyzed using the seven DNA markers within the QTL peak before fully implementing marker assisted selection in a cotton breeding program.

关键词： Cotton Fiber quality Fiber strength MAGIC population qFS-c7-1

Efficacy of chlorfenapyr against adult Tribolium castaneum exposed on concrete＂ effects of exposure interval, concentration and the presence of a food source after exposure

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Insect Science 2009年第2期16卷 157-163页

作者： Frank H. Arthur usda-ars Grain Marketing and Production Research Center Manhattan Kansas USA

Chlorfenapyr, an insecticidal pyrrole, was applied to concrete arenas at concentrations of 1. 1, 0.825, 0.55, and 0.275 g of active ingredient [AI]/m^2. Adult Tribolium castaneum （Herbst）, the red flour beetle, were exposed for 2, 4, or 8 h at each concentration, then removed and held either with or without food （wheat flour） for 7 days. Survival was assessed when the beetles were removed fi＇om the exposure arenas and daily during the post- exposure period. In the presence of food, survival was high regardless of concentration and the day on which post-treatment survival was assessed, but survival did decrease as the exposure period increased from 4 to 8 h. When the beetles were not given food after exposure, survival at each concentration and exposure period declined during the 1-week post- exposure assessments. This pattern of decrease could be described by linear and non-linear equations. Results show the presence of food material greatly compromised effectiveness of the insecticide, and emphasize the importance of cleaning and sanitation in conjunction with insecticide treatments.

关键词： chlorfenapyr efficacy sanitation Tribolium castaneum

Monitoring of brown stink bug (Hemiptera: Pentatomidae) population dynamics in corn to predict its abundanee using weather data

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Insect Science 2019年第3期26卷 536-544页

作者： Xinzhi Ni Ted E. Cottrell G. David Buntin Xianchun Li Wei Wang Hong Zhuang usda-ars Crop Genetics and Breeding Research Unit Tifton Georgia USA usda-ars Southeastern Fruit and Tree Nut Research Laboratory Byron Georgia USA Department of Entomology University of Georgia Griffin Georgia USA Department of Entomology University of Arizona Tucson Arizona USA College of Engineering China Agricultural University Beijing China usda-ars Quality and Safety Assessment Research Unit Athens Georgia USA

The brown stink bug (BSB), Euschistus servus (Say)(Hemiptera: Pentatomidae), is a serious economic pest of corn production in the southeastern United States. The BSB population dynamics was mon itored for 17 weeks from tasseling to preharvest of corn plants (i.e., late May to mid-September) using pheromone traps in three corn fields from 2005 to 2009. The trap data showed two peaks in early June and mid-August, respectively. The relationship between trap catch and pregrowing season weather data was examined using correlation and stepwise multiple factor regression analyses. Weather indices used for the analyses were accumulated growing degree day (AGDD), number of days with minimum temperature below 0℃(Subz), accumulated daily maximum (AMaxT) and minimum temperatures (AMinT) and rainfall (ARain). The weather indices were calculated with lower (10℃) and upper (35℃) as biological thresholds. The parameters used in regression analysis were seasonal abundance (or overall mean of BSB adult catch)(BSBm), number of BSB adults caught at a peak (PeakBSB), and peak week (Peakwk). The BSBm was negatively related to high temperature (AmaxT or AGDD) consistently, whereas IstPeakBSB was positively correlated to both ARain and Subz, irrespective of weather data durations (the first 4, 4.5, and 5 months). In contrast, the 7-month weather data (AGDD7) were negatively correlated to the BSBm only, but not correlated to the second PeakBSB. The 5-year monitoring study demonstrated that weather data can be used to predict the BSB abundance at its first peak in tasseling corn fields in the southeastern U.S. states.

关键词： Euschistus servus first trap catch peak pheromone trap catch population dynamics stepwise regression modeling weekly mean

Predicting the dynamics of local adaptation in invasive species

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Journal of Arid Land 2013年第3期5卷 268-274页

作者： Erin K ESPELAND usda-ars Pest Management Research Unit Sidney MT 59270USA

An invasive plant species may restrict its spread to only one type of habitat, or, after some time, may continue to spread into a different, often stressful, secondary, habitat. The question of whether evolution is required for an invasive species to spread from one habitat to another is currently hotly debated. In order for local adaptation to occur, genetic variation must be present within invasive populations. In this paper, I focus on the effect of habitat on the maintenance of genetic variation during the lag phase, the phase of population stability prior to expansion. Genetic diversity in invasive plant populations accumulates through multiple introductions, gene flow, mutation, and hybridization, but diversity is maintained by population level processes influencing effective population size （Ne）. I show that when the plastic response to the environment results in little variation in reproductive output among indi- viduals, Ne is maximized and genetic variation is maintained. Established models of plant competition show that below-ground competition reduces the variation in reproductive output, whereas competition for light increases variation in reproductive output. The same environments that maintain high Ne also reduce the opportunity for se- lection and minimize the response to selection, and thus the effects of the environment are synchronized to prevent genetic purges. When the primary invasion habitat supports high Ne, conditions are ripe for local adaptation to a secondary habitat, particularly if the secondary habitat has high opportunity for selection. When the primary invasion habitat supports low Ne, genetic diversity is less likely to be sufficient for local adaptation to secondary habitat to occur.

关键词： canalization phenotypic plasticity population expansion secondary invasion