Nicholas Collins

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Failure of pathogenic fungi to breach the plant cell wall constitutes a major component of immunity of non-host plant species--species outside the pathogen host range--and accounts for a proportion of aborted infection attempts on 'susceptible' host plants (basal resistance). Neither form of penetration resistance is understood at the molecular level. We(More)
Many of the plant disease resistance genes that have been isolated encode proteins with a putative nucleotide binding site and leucine-rich repeats (NBS-LRR resistance genes). Oligonucleotide primers based on conserved motifs in and around the NBS of known NBS-LRR resistance proteins were used to amplify sequences from maize genomic DNA by polymerase chain(More)
The Rp1-D gene for resistance to maize common rust (Puccinia sorghi) is a member of a complex locus (haplotype) composed of Rp1-D and approximately eight other gene homologs. The identity of Rp1-D was demonstrated by using two independent gene-tagging approaches with the transposons Mutator and Dissociation. PIC20, a disease resistance (R) gene analog probe(More)
Lack of the barley (Hordeum vulgare) seven-transmembrane domain MLO protein confers resistance against the fungal pathogen Blumeria graminis f. sp. hordei (Bgh). To broaden the basis for MLO structure/function studies, we sequenced additional mlo resistance alleles, two of which confer only partial resistance. Wild-type MLO dampens the cell wall-restricted(More)
Both limiting and toxic soil concentrations of the essential micronutrient boron represent major limitations to crop production worldwide. We identified Bot1, a BOR1 ortholog, as the gene responsible for the superior boron-toxicity tolerance of the Algerian barley landrace Sahara 3771 (Sahara). Bot1 was located at the tolerance locus by high-resolution(More)
Aluminum toxicity is a major problem in agriculture worldwide. Among the cultivated Triticeae, rye (Secale cereale L.) is one of the most Al tolerant and represents an important potential source of Al tolerance for improvement of wheat. The Alt4 Al-tolerance locus of rye contains a cluster of genes homologous to the single-copy Al-activated malate(More)
Rp1 is a complex rust resistance locus of maize. The HRp1-D haplotype is composed of Rp1-D and eight paralogues, seven of which also code for predicted nucleotide binding site-leucine rich repeat (NBS-LRR) proteins similar to the Rp1-D gene. The paralogues are polymorphic (DNA identities 91-97%), especially in the C-terminal LRR domain. The remaining family(More)
The majority of verified plant disease resistance genes isolated to date are of the NBS-LRR class, encoding proteins with a predicted nucleotide binding site (NBS) and a leucine-rich repeat (LRR) region. We took advantage of the sequence conservation in the NBS motif to clone, by PCR, gene fragments from barley representing putative disease resistance(More)
Toxicity due to high levels of soil boron (B) represents a significant limitation to cereal production in some regions, and the Bo1 gene provides a major source of B toxicity tolerance in bread wheat (Triticum aestivum L.). A novel approach was used to develop primers to amplify and sequence gene fragments specifically from the Bo1 region of the hexaploid(More)