Cole crop production (broccoli, cabbage, and cauliflower)

The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311

Genetic Analysis of a Disease Resistance Gene from Loblolly Pine

Rapid advances in molecular genetics provide great opportunities for studies of host defense mechanisms. Examination of plant responses to disease at the cellular and molecular level permits both discovery of changes in gene expression in the tissues attacked by pathogens, and identification of genetic components involved in the interaction between host and pathogens. Expression of specific proteins, which is one type of defense mechanism, may offer the host a weapon to protect it from invasion of pathogenic attack. Recently, we have isolated a novel antimicrobial protein gene (PtAMP) from loblolly pine during our gene screening effort. Studies of molecular characterization show that the PtAMP gene shares limited similarity with previously reported antimicrobial proteins in the amino acid sequences, but it contains some common features, e.g. DNA sequences and protein structure, with those antimicrobial proteins. The function of this novel antimicrobial gene has been analyzed at the in vitro and in vivo levels. Antimicrobial assay data showed that the purified PtAMP protein has strong inhibitory activities against a variety of pathogenic bacteria and fungi. Furthermore, the gene for the PtAMP was transferred into the tobacco genome via Agrobacterium-mediated transformation. Ectopic expression of the PtAMP protein in transgenic tobacco plants confers resistance to bacterial and fungal phytopathogens. Our data suggest that the PtAMP gene has the potential through genetic manipulation to protect plants from a wide range of plant pathogens. Analysis of its function provides further understanding of plant defense mechanisms in loblolly pine.Papers and abstracts from the 27th Southern Forest Tree Improvement Conference held at Oklahoma State University in Stillwater, Oklahoma on June 24-27, 2003

A Coordinated Effort to Manage Soybean Rust in North America: A Success Story in Soybean Disease Monitoring

Existing crop monitoring programs determine the incidence and distribution of plant diseases and pathogens and assess the damage caused within a crop production region. These programs have traditionally used observed or predicted disease and pathogen data and environmental information to prescribe management practices that minimize crop loss (3,69). Monitoring programs are especially important for crops with broad geographic distribution or for diseases that can cause rapid and great economic losses. Successful monitoring programs have been developed for several plant diseases, including downy mildew of cucurbits, Fusarium head blight of wheat, potato late blight, and rusts of cereal crops (13,36,51,80)

No-till cropping systems in Oklahoma

The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311

Expression of a Novel Antimicrobial Peptide Penaeidin4-1 in Creeping Bentgrass (Agrostis stolonifera L.) Enhances Plant Fungal Disease Resistance

BACKGROUND: Turfgrass species are agriculturally and economically important perennial crops. Turfgrass species are highly susceptible to a wide range of fungal pathogens. Dollar spot and brown patch, two important diseases caused by fungal pathogens Sclerotinia homoecarpa and Rhizoctonia solani, respectively, are among the most severe turfgrass diseases. Currently, turf fungal disease control mainly relies on fungicide treatments, which raises many concerns for human health and the environment. Antimicrobial peptides found in various organisms play an important role in innate immune response. METHODOLOGY/PRINCIPAL FINDINGS: The antimicrobial peptide - Penaeidin4-1 (Pen4-1) from the shrimp, Litopenaeus setiferus has been reported to possess in vitro antifungal and antibacterial activities against various economically important fungal and bacterial pathogens. In this study, we have studied the feasibility of using this novel peptide for engineering enhanced disease resistance into creeping bentgrass plants (Agrostis stolonifera L., cv. Penn A-4). Two DNA constructs were prepared containing either the coding sequence of a single peptide, Pen4-1 or the DNA sequence coding for the transit signal peptide of the secreted tobacco AP24 protein translationally fused to the Pen4-1 coding sequence. A maize ubiquitin promoter was used in both constructs to drive gene expression. Transgenic turfgrass plants containing different DNA constructs were generated by Agrobacterium-mediated transformation and analyzed for transgene insertion and expression. In replicated in vitro and in vivo experiments under controlled environments, transgenic plants exhibited significantly enhanced resistance to dollar spot and brown patch, the two major fungal diseases in turfgrass. The targeting of Pen4-1 to endoplasmic reticulum by the transit peptide of AP24 protein did not significantly impact disease resistance in transgenic plants. CONCLUSION/SIGNIFICANCE: Our results demonstrate the effectiveness of Pen4-1 in a perennial species against fungal pathogens and suggest a potential strategy for engineering broad-spectrum fungal disease resistance in crop species

A Coordinated Effort to Manage Soybean Rust in North America: A Success Story in Soybean Disease Monitoring

Existing crop monitoring programs determine the incidence and distribution of plant diseases and pathogens and assess the damage caused within a crop production region. These programs have traditionally used observed or predicted disease and pathogen data and environmental information to prescribe management practices that minimize crop loss (3,69). Monitoring programs are especially important for crops with broad geographic distribution or for diseases that can cause rapid and great economic losses. Successful monitoring programs have been developed for several plant diseases, including downy mildew of cucurbits, Fusarium head blight of wheat, potato late blight, and rusts of cereal crops (13,36,51,80)

Identification of quantitative trait loci associated with maize resistance to bacterial leaf streak

Bacterial leaf streak (BLS), a foliar disease of maize (Zea mays L.) caused by Xanthomonas vasicola pv. vasculorum, recently emerged in the Americas as a disease of major importance. Little is known about the disease cycle, and consequently, management is difficult. No chemical control is available. Host resistance will likely play a major role in controlling the disease, but to date, no data regarding the resistance of maize germplasm to X. vasicola pv. vasculorum have been published. The objective of this study was to examine the genetic architecture of resistance to BLS. We conducted quantitative trait locus (QTL) mapping for BLS resistance in three maize populations: the Z022 (B73 × Oh43 recombinant inbred line) nested association mapping (NAM) population, the Z023 (B73 × Oh7B recombinant inbred line) NAM population, and the DRIL78 (NC344 × Oh7B chromosome segment substitution line) population. A total of five QTL were detected across two of the mapping populations. Of the QTL detected, one conferred a moderate effect, whereas the others conferred small effects. We also examined the relationship between resistance to BLS and resistance to three foliar diseases of maize, which had been mapped previously. The only significant correlation we found for BLS was with northern corn leaf blight [caused by Exserohilum turcicum (Pass.) K. J. Leonard & Suggs] in one of the populations, although two of the five BLS regions were involved in resistance to other diseases. These data will be useful for developing maize varieties resistant to BLS to mitigate the impact of bacterial leaf streak on maize production.This is a manuscript of an article published as Qiu, Yuting, Christopher Kaiser, Clarice Schmidt, Kirk Broders, Alison E. Robertson, and Tiffany M. Jamann. "Identification of quantitative trait loci associated with maize resistance to bacterial leaf streak." Crop Science 60, no. 1 (2020): 226-237. doi:10.1002/csc2.20099. Posted with permission.</p