Transgene-based analysis of the MIC-3 gene provides the first report of a cotton gene having a direct role in mediating cotton resistance to root-knot nematode. Major quantitative trait loci have been mapped to Upland cotton (Gossypium hirsutum L.) chromosomes 11 and 14 that govern the highly resistant phenotype in response to infection by root-knot nematode (RKN; Meloidogyne incognita); however, nearly nothing is known regarding the underlying molecular determinants of this RKN-resistant phenotype.
View Article and Find Full Text PDFTransgenic tobacco (Nicotiana tabacum) lines were engineered to ectopically over-express AtMYB90 (PAP2), an R2-R3 Myb gene associated with regulation of anthocyanin production in Arabidopsis thaliana. Independently transformed transgenic lines, Myb27 and Myb237, accumulated large quantities of anthocyanin, generating a dark purple phenotype in nearly all tissues. After self-fertilization, some progeny of the Myb27 line displayed an unexpected pigmentation pattern, with most leaves displaying large sectors of dramatically reduced anthocyanin production.
View Article and Find Full Text PDFBackground: In part due to the ease of visual detection of phenotypic changes, anthocyanin pigment production has long been the target of genetic and molecular research in plants. Specific members of the large family of plant myb transcription factors have been found to play critical roles in regulating expression of anthocyanin biosynthetic genes and these genes continue to serve as important tools in dissecting the molecular mechanisms of plant gene regulation.
Findings: A spontaneous mutation within the coding region of an Arabidopsis 35S::AtMYB90 transgene converted the activator of plant-wide anthocyanin production to a dominant-negative allele (PG-1) that inhibits normal pigment production within tobacco petals.
Short directly-repeated (DR) DNA enhancer elements of plant viral origin were analyzed for their ability, both individually and in combination, to influence in vivo transcription when inserted upstream from a minimal CaMV35S promoter. Synthetic promoters containing multiple copies and/or combinations of DR cassettes were tested for their effect upon reporter gene (luciferase) expression using an Agrobacteria-based leaf-infiltration transient assay and within stably transformed plants (Nicotiana tabacum). Transgenic plants harboring constructs containing different numbers or combinations of DR cassettes were further tested to look for tissue-specific expression patterns and potential promoter response to the infiltration process employed during transient expression.
View Article and Find Full Text PDFPlants are constantly challenged with various abiotic stresses in their natural environment. Elevated temperatures have a detrimental impact on overall plant growth and productivity. Many plants increase their tolerance to high temperatures through an adaptation response known as acquired thermotolerance.
View Article and Find Full Text PDFPlants, as sessile organisms, employ multiple mechanisms to adapt to the seasonal and daily temperature fluctuations associated with their habitats. Here, we provide genetic and physiological evidence that the FtsH11 protease of Arabidopsis contributes to the overall tolerance of the plant to elevated temperatures. To identify the various mechanisms of thermotolerance in plants, we isolated a series of Arabidopsis thaliana thermo-sensitive mutants (atts) that fail to acquire thermotolerance after pre-conditioning at 38 degrees C.
View Article and Find Full Text PDFAn in vivo assay system for analyzing transient luciferase expression in tobacco leaves infused with Agrobacterium tumefaciens is described. The system makes use of A. tumefaciens harboring T-DNA vectors containing either an intron-containing firefly (Photinus pyralis) luciferase (EC 1.
View Article and Find Full Text PDFBryophytes are a non-monophyletic group of three major lineages (liverworts, hornworts, and mosses) that descend from the earliest branching events in the phylogeny of land plants. We postulate that desiccation tolerance is a primitive trait, thus mechanisms by which the first land plants achieved tolerance may be reflected in how extant desiccation-tolerant bryophytes survive drying. Evidence is consistent with extant bryophytes employing a tolerance strategy of constitutive cellular protection coupled with induction of a recovery/repair mechanism upon rehydration.
View Article and Find Full Text PDFThe conserved late element (CLE) was originally identified as an evolutionarily conserved DNA sequence present in geminiviral intergenic regions. CLE has subsequently been observed in promoter sequences of bacterial (T-DNA) and plant origin, suggesting a role in plant and plant viral gene regulation. Synthetic DNA cassettes harboring direct repeats of the CLE motif were placed upstream from a -46 to +1 minimal CaMV 35S promoter-luciferase reporter gene and reporter activity characterized in Nicotiana species during both transient and stable expression.
View Article and Find Full Text PDFBackground: The geminivirus and nanovirus families of DNA plant viruses have proved to be a fertile source of viral genomic sequences, clearly demonstrated by the large number of sequence entries within public DNA sequence databases. Due to considerable conservation in genome organization, these viruses contain easily identifiable intergenic regions that have been found to contain multiple DNA sequence elements important to viral replication and gene regulation. As a first step in a broad screen of geminivirus and nanovirus intergenic sequences for DNA segments important in controlling viral gene expression, we have 'mined' a large set of viral intergenic regions for transcriptional enhancers.
View Article and Find Full Text PDFPCR has become one of the most popular techniques in functional genomics. Projects in both forward and reverse genetics routinely require PCR amplification of thousands of samples. Processing samples to extract DNA of sufficient purity for PCR is often a limiting step.
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