Characterization of genetic diversity and linkage disequilibrium of ZmLOX4 and ZmLOX5 loci in maize

PLoS One. 2013;8(1):e53973. doi: 10.1371/journal.pone.0053973. Epub 2013 Jan 24.

Abstract

Maize (Zea mays L.) lipoxygenases (ZmLOXs) are well recognized as important players in plant defense against pathogens, especially in cross kingdom lipid communication with pathogenic fungi. This study is among the first to investigate genetic diversity at important gene paralogs ZmLOX4 and ZmLOX5. Sequencing of these genes in 400 diverse maize lines showed little genetic diversity and low linkage disequilibrium in the two genes. Importantly, we identified one inbred line in which ZmLOX5 has a disrupted open reading frame, a line missing ZmLOX5, and five lines with a duplication of ZmLOX5. Tajima's D test suggests that both ZmLOX4 and ZmLOX5 have been under neutral selection. Further investigation of haplotype data revealed that within the ZmLOX family members only ZmLOX12, a monocot specific ZmLOX, showed strong linkage disequilibrium that extends further than expected in maize. Linkage disequilibrium patterns at these loci of interest are crucial for future candidate gene association mapping studies. ZmLOX4 and ZmLOX5 mutations and copy number variants are under further investigation for crop improvement.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Chromosome Mapping
  • Chromosomes, Plant
  • Gene Deletion
  • Gene Dosage
  • Gene Duplication
  • Genetic Loci*
  • Haplotypes
  • Isoenzymes / genetics
  • Linkage Disequilibrium*
  • Lipoxygenases / genetics*
  • Open Reading Frames
  • Phenotype
  • Plant Proteins / genetics*
  • Polymorphism, Genetic*
  • Selection, Genetic
  • Sequence Analysis, DNA
  • Zea mays / enzymology
  • Zea mays / genetics*

Substances

  • Isoenzymes
  • Plant Proteins
  • Lipoxygenases

Grants and funding

This study was funded by the USDA National Institute of Food and Agriculture (NIFA) Agriculture and Food Research Initiative (AFRI) (http://www.nifa.usda.gov/funding/rfas/afri.html) Plant Breeding and Education grant #2010-85117-20539, the National Science Foundation (www.nsf.gov) grant # IOS-0951272, and the Texas Corn Producers Board (www.texascorn.org). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.