No abstract

RAPDs (Randomly Amplified Polymorphic DNAs) were used to discriminate among 23 cultivars of oilseed rape (Brassica napus) selected from several breeding programs. A set of 100 random sequence 10-mer primers were tested, of which 70 produced bands and 22 showed evidence of polymorphism. A selection of six primers produced 23 polymorphic bands of between 300 to 2200 base pairs in size, sufficient to distinguish between the cultivars. An analysis of seed of five cultivars obtained from four different sites showed stability of banding pattern over source of seed. The analysis was repeated using four different thermocyclers, each of which produced the same band pattern. UPGMA cluster analysis indicates that the relationships among some of the cultivars is closer for those from the same breeding program than for those from different programs. The results of this study show that RAPDs can be used as a method of identification for oilseed rape cultivars.

No abstract

To identify genes effective against the blackleg fungus Leptosphaeria maculans (Phoma lingam), we have transformed canola (Brassica napus) with four pea (Pisum sativum) genes under constitutive control by the cauliflower mosaic virus 35S promoter: PR10.1, chitinase, DRR206, and defensin. Transgenic lines containing single-copy T-DNA insertions for each gene were screened for both seedling (cotyledonary) and adult plant resistance. Lines for which pea DRR206 mRNA was expressed showed decreased disease scores, compared with non-expressing transgenic lines. Transgenic plants expressing pea defensin showed a slight enhancement of resistance, while for PR10 and chitinase transgenics there was little or no enhancement of resistance. Resistance to L. maculans cosegregated with DRR206 transgenes. Extracts from DRR206 and defensin transgenic plants inhibited fungal germination in vitro. DRR206 transgenic plants also demonstrated decreased hyphal growth at inoculation sites. While the precise function of DRR206 remains to be determined, these results suggest that it does play an important role in defense against fungi.

Pathogenesis-related (PR) proteins are expressed by virtually all plants in response to pathogen infection and, in many cases, in response to abiotic stresses as well and include the PR10 family. However, the precise roles of the PR10 protein family in abiotic stress responses are not clear. In this paper we report, for the first time, that the constitutive expression of a pea PR10 gene in Brassica napus enhances their germination and growth in the presence of NaCl. Our findings are discussed within the context of PR10 protein function and their utility in engineering stress tolerant crops.

No abstract

The most common types of nucleotide sequence data analyses and handling can be done more conveniently and inexpensively on microcomputers than on large time-sharing systems. We present a package of computer programs for the analysis of DNA and RNA sequence data which overcomes many of the limitations imposed by microcomputers, while offering most of the features of programs commonly available on large computers, including sequence numbering and translation, restriction site and homology searches with dot-matrix plots, nucleotide distribution analysis, and graphic display of data. Most of the programs were written in Standard Pascal (on an Apple II computer) to facilitate portability to other micro-, mini-, and and mainframe computers.

To measure transcript levels for individual members of the Cab (chlorophyll a/b protein) multigene family in pea under a range of developmental situations, we developed a system using cDNA synthesis, the polymerase chain reaction (PCR), and chemiluminescence detection. In order to design gene-specific PCR primers for all genes, a partial genomic clone for a fifth, Type I LHCII (light-harvesting complex of photosystem II) gene, Cab-9 The Cab-9 sequence appears in the Genbank/EMBL databases under the accession number M86906 , was isolated and sequenced. All seven known Cab genes in pea are expressed in light-grown buds and leaves, including several genes previously known only from genomic clones. There appear to be at least two groups of Cab genes in pea which differ in their response to light and development. The first group (consisting of Cab-8, AB96, Cab-215 and Cab-315) includes Type I, Type II and Type III genes, shows a relatively strong response to red light, and has bud transcript levels similar to or slightly higher than leaves. The second group, consisting of the Type I genes Cab-9, AB80 and AB66, shows little or no transcript accumulation 24 h after a red light pulse, and has higher transcript levels in leaves than in buds. Transcript levels for genes in this second group appear to be lower than those of the first group in all developmental situations examined. These data indicate that there has been an evolutionary divergence of the responses to light and development among the Type I LHCII genes.