Evolution of insect resistance to transgenic crops containing Bacillus thuringiensis (Bt) genes is a serious threat to the sustainability of this technology. However, field resistance related to the reduced efficacy of Bt maize has not been documented in any lepidopteran pest in the mainland U.S. after 18 years of intensive Bt maize planting. Here we report compelling evidence of field resistance in the fall armyworm, Spodoptera frugiperda (J.E. Smith), to Cry1F maize (TC 3507) in the southeastern region of the U.S. An F2 screen showed a surprisingly high (0.293) Cry1F resistance allele frequency in a population collected in 2011 from non-Bt maize in south Florida. Field populations from non-Bt maize in 2012–2013 exhibited 18.8-fold to >85.4-fold resistance to purified Cry1F protein and those collected from unexpectedly damaged Bt maize plants at several locations in Florida and North Carolina had >85.4-fold resistance. In addition, reduced efficacy and control failure of Cry1F maize against natural populations of S. frugiperda were documented in field trials using Cry1F-based and pyramided Bt maize products in south Florida. The Cry1F-resistant S. frugiperda also showed a low level of cross-resistance to Cry1A.105 and related maize products, but not to Cry2Ab2 or Vip3A. The occurrence of Cry1F resistance in the U.S. mainland populations of S. frugiperda likely represents migration of insects from Puerto Rico, indicating the great challenges faced in achieving effective resistance management for long-distance migratory pests like S. frugiperda.

In attempts to develop a method of introducing DNA into Pyrococcus furiosus, we discovered a variant within the wild-type population that is naturally and efficiently competent for DNA uptake. A pyrF gene deletion mutant was constructed in the genome, and the combined transformation and recombination frequencies of this strain allowed marker replacement by direct selection using linear DNA. We have demonstrated the use of this strain, designated COM1, for genetic manipulation. Using genetic selections and counterselections based on uracil biosynthesis, we generated single-and double-deletion mutants of the two gene clusters that encode the two cytoplasmic hydrogenases. The COM1 strain will provide the basis for the development of more sophisticated genetic tools allowing the study and metabolic engineering of this important hyperthermophile.It would be difficult to overestimate the contribution of genetic manipulation to the study of any biological system, and it is an essential tool for the metabolic engineering of biosynthetic and substrate utilization pathways. This is particularly true for the archaea since, in spite of their environmental and industrial importance, coupled with their unique molecular features, much remains to be learned about their biology (2). The marine hyperthermophilic anaerobe Pyrococcus furiosus is of special interest not only for its ability to grow optimally at 100°C and the implications of this trait for its biology but also for industrial applications of its enzymes, as well as its capacity to produce hydrogen efficiently (4, 13, 44). The ability to apply genetic analyses of P. furiosus to underpin existing biochemical and molecular studies will contribute greatly to the establishment of P. furiosus as a model organism, particularly for biological hydrogen production.The development of genetic systems in the archaea, in general, presents many unique challenges given the extreme growth requirements of many of these organisms. To date, genetic systems of various levels of sophistication have been developed for representatives of all major groups of archaea, including halophiles, methanogens, thermoacidophiles, and hyperthermophiles (2,6,30,40,43,46). A variety of transformation methods are being used, including electroporation, heat shock with or without CaCl 2 treatment, phage-mediated transduction, spheroplast transformation, liposomes, and, very recently, even conjugation with Escherichia coli (2, 12). Transformation via natural competence has been reported in three archaeal species, in comparison to over 60 bacterial species that are known to exhibit this trait (16,36). Two of them are the methanogens Methanococcus voltae PS (7, 27) and Methanobacterium thermoautotrophicum Marburg (47); however, transformation frequencies were low, and there have been no follow-up studies regarding natural competence. The other is the hyperthermophile Thermococcus kodakarensis, which has an optimal growth temperature of 85°C. Its natural competence has enabled the development of genetic tools fo...

The corn earworm, Helicoverpa zea (Boddie), is a major pest of Bacillus thuringiensis (Bt) maize and cotton in the U.S.. Reduced efficacy of Bt plants expressing Cry1 and Cry2 against H. zea has been reported in some areas of the U.S.. In this study, we evaluated the occurrence and ear damage of H. zea on transgenic Bt maize expressing Cry proteins or a combination of Vip3A and Cry proteins in the field in Texas in 2018. We found that the occurrence of H. zea larvae and the viable kernel damage area on the ear were not different between non-Bt maize and Bt maize expressing Cry1A.105+Cry2Ab2 and Cry1Ab+Cry1F proteins. A total of 67.5% of the pyramided Bt maize expressing Cry1Ab+Cry1F+Vip3A was damaged by 2nd–4th instar larvae of H. zea. Diet bioassays showed that the resistance ratio against Vip3Aa51 for H. zea obtained from Cry1Ab+Cry1F+Vip3A maize was 20.4 compared to a field population collected from Cry1F+Cry1A.105+Cry2Ab2 maize. Leaf tissue bioassays showed that 7-day survivorship on WideStrike3 (Cry1F+Cry1Ac+Vip3A) cotton leaves was significantly higher for the H. zea population collected from Cry1Ab+Cry1F+Vip3A maize than for a Bt-susceptible laboratory population. The results generated from this study suggest that H. zea has evolved practical resistance to Cry1 and Cry2 proteins. Therefore, it is crucial to ensure the sustainable use of the Vip3A technology in Bt maize and cotton.

Many cancer therapeutics target DNA and exert cytotoxicity through the induction of DNA damage and inhibition of transcription. We report that a DNA minor groove binding hairpin pyrroleimidazole (Py-Im) polyamide interferes with RNA polymerase II (RNAP2) activity in cell culture. Polyamide treatment activates p53 signaling in LNCaP prostate cancer cells without detectable DNA damage. Genome-wide mapping of RNAP2 binding shows reduction of occupancy, preferentially at transcription start sites, but occupancy at enhancer sites is unchanged. Polyamide treatment results in a time-and dose-dependent depletion of the RNAP2 large subunit RPB1 that is preventable with proteasome inhibition. This polyamide demonstrates antitumor activity in a prostate tumor xenograft model with limited host toxicity.minor groove binder | small molecule transcription inhibitor | ChIP-Seq