ARS | Publication request: GENOMIC ORGANIZATION OF DISEASE AND INSECT RESISTANCE GENES IN MAIZE

Submitted to: Molecular Plant-Microbe Interactions
Publication Type: Review Article
Publication Acceptance Date: July 28, 1995
Publication Date: N/A

Technical Abstract: With the advent of restriction fragment length polymorphism (RFLP) analysis, there has been a large increase in the number of single-factor genes and quantitative trait loci (QTL) for genes controlling resistance to diseases and insects located on the maize genetic map. During the construction of a fine-structure map around a gene for virus resistance on chromosome six, we noted that two other resistance genes were located in the same region. To determine if similar clusters of resistance genes occurred throughout the maize genome, we performed a compilation and analysis of the genomic map positions of all documented single gene and QTL loci for disease and insect resistance in maize. By placing loci in chromosomal bins we demonstrated that resistance loci are clustered at many locations in the maize genome. Many examples are noted of QTL and single factor genes mapping to the same chromosomal bin locations. What is striking about these clusters is the spectrum of pathogens/pests and types of host-pathogen/pest interactions represented in many clusters. For instance on chromosome 3, bins 4 and 5 contain single-factor genes for resistance to common rust, wheat streak mosaic virus, and maize mosaic virus, and QTL for resistance to Fusarium stalk rot and European corn borer. Although the clusters contain genes for resistance to diverse pathogens and pests, these genes may be structurally related as either members of genes families involved in signal transduction pathways or as transcription activators. Implications of the clustering of resistance loci on gene mapping are discussed.