Two Theobroma cacao genotypes with contrasting pathogen tolerance show aberrant transcriptional and ROS responses after salicylic acid treatment

Andrew S. Fister, Shawn T. O'Neil, Zi Shi, Yufan Zhang, Brett M. Tyler, Mark J. Guiltinan, Siela N. Maximova

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Understanding the genetic basis of pathogen susceptibility in various crop plants is crucial to increasing the stability of food, feed, and fuel production. Varietal differences in defence responses provide insights into the mechanisms of resistance and are a key resource for plant breeders. To explore the role of salicylic acid in the regulation of defence in cacao, we demonstrated that SA treatment decreased susceptibility to a pod rot pathogen, Phytophthora tropicalis in two genotypes, Scavina 6 and Imperial College Selection 1, which differ in their resistance to several agriculturally important pathogens. Transient overexpression of TcNPR1, a major transcriptional regulator of the SA-dependent plant immune system, also increased pathogen tolerance in cacao leaves. To explore further the genetic basis of resistance in cacao, we used microarrays to measure gene expression profles after salicylic acid (SA) treatment in these two cacao genotypes. The two genotypes displayed distinct transcriptional responses to SA. Unexpectedly, the expression profle of the susceptible genotype ICS1 included a larger number of pathogenesis-related genes that were induced by SA at 24 h after treatment, whereas genes encoding many chloroplast and mitochondrial proteins implicated in reactive oxygen species production were up-regulated in the resistant genotype, Sca6. Sca6 accumulated signifcantly more superoxide at 24 h after treatment of leaves with SA. These experiments revealed critical insights regarding the molecular differences between cacao varieties, which will allow a better understanding of defence mechanisms to help guide breeding programmes.

Original languageEnglish (US)
Pages (from-to)6245-6258
Number of pages14
JournalJournal of experimental botany
Volume66
Issue number20
DOIs
StatePublished - 2015

All Science Journal Classification (ASJC) codes

  • Physiology
  • Plant Science

Fingerprint Dive into the research topics of 'Two Theobroma cacao genotypes with contrasting pathogen tolerance show aberrant transcriptional and ROS responses after salicylic acid treatment'. Together they form a unique fingerprint.

Cite this