Global changes in gene expression of grapefruit peel tissue in response to the yeast biocontrol agent Metschnikowia fructicola

Mol Plant Pathol. 2012 May;13(4):338-49. doi: 10.1111/j.1364-3703.2011.00750.x. Epub 2011 Oct 21.

Abstract

To gain a better understanding of the molecular changes taking place in citrus fruit tissue following the application of the yeast biocontrol agent Metschnikowia fructicola, microarray analysis was performed on grapefruit surface wounds using an Affymetrix Citrus GeneChip. Using a cut-off of P < 0.05 and a 1.5-fold change difference as biologically significant, the data indicated that 1007 putative unigenes showed significant expression changes following wounding and yeast application relative to wounded controls. Microarray results of selected genes were validated by reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR). The data indicated that yeast application induced the expression of the genes encoding Respiratory burst oxidase (Rbo), mitogen-activated protein kinase (MAPK) and mitogen-activated protein kinase kinase (MAPKK), G-proteins, chitinase (CHI), phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS) and 4-coumarate-CoA ligase (4CL). In contrast, three genes, peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT), were down-regulated in grapefruit peel tissue treated with yeast cells. Moreover, suppression was correlated with significantly higher levels of hydrogen peroxide, superoxide anion and hydroxyl radical production in yeast-treated surface wounds. Interestingly, large amounts of hydrogen peroxide were detected inside yeast cells recovered from wounded fruit tissue, indicating the ability of the yeast to activate reactive oxygen species when it is in contact with plant tissue. This study provides the first global picture of gene expression changes in grapefruit in response to the yeast antagonist M. fructicola.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Citrus paradisi / genetics*
  • Citrus paradisi / immunology
  • Citrus paradisi / microbiology*
  • Citrus paradisi / physiology
  • Cluster Analysis
  • Gene Expression Profiling*
  • Gene Expression Regulation, Plant*
  • Genes, Plant / genetics
  • Hydrogen Peroxide / metabolism
  • Hydroxyl Radical / metabolism
  • Metschnikowia / cytology
  • Metschnikowia / metabolism
  • Metschnikowia / physiology*
  • Microscopy, Confocal
  • Organ Specificity / genetics
  • Pest Control, Biological*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction / genetics
  • Stress, Physiological / genetics
  • Superoxides / metabolism
  • Time Factors
  • Transcriptome / genetics

Substances

  • Superoxides
  • Hydroxyl Radical
  • Hydrogen Peroxide