Profiling of secondary metabolites in blue lupin inoculated with Phytophthora cinnamomi following phosphite treatment

Abstract

In order to discover phytochemicals that are potentially bioactive against Phytophthora cinnamomi, (a soilborne plant pathogen) a metabolite profiling protocol for investigation of metabolic changes in Lupinus angustifolius L. plant roots in response to pathogen challenge has been established. Analysis of the metabolic profiles from healthy and P. cinnamomi-inoculated root tissue with high resolution mass spectrometry and nuclear magnetic resonance spectroscopy confirmed that although susceptible, L. angustifolius upregulated a defence associated genistein and 2 0 -hydroxygenisteinbased isoflavonoid and a soyasapogenol saponin at 12 h post inoculation which increased in concentration at 72 h post inoculation. In contrast to the typical susceptible interaction, the application of a phosphorous-based treatment to L. angustifolius foliage 48 h before P. cinnamomi challenge negated the ability of the pathogen to colonise the root tissue and cause disease. Importantly, although the root profiles of water-treated and phosphite-treated plants post pathogen inoculation contained the same secondary metabolites, concentration variations were observed. Accumulation of secondary metabolites within the P. cinnamomi-inoculated plants confirms that pathogen ingress of the root interstitially occurs in phosphite-treated plants, confirming a direct mode of action against the pathogen upon breaching the root cells.Additional keywords: mass spectrometry, NMR, plant defence mechanisms, plant defense mechanisms, phosphite.

Dual RNA-Sequencing of Eucalyptus nitens during Phytophthora cinnamomi Challenge Reveals Pathogen and Host Factors Influencing Compatibility

“…There are several up-regulated genes with GO annotations associated with flavonoid biosynthesis. Susceptible Lupinus angustifolius up-regulated the flavonoid genistein in response to P. cinnamomi (Gunning et al, 2013 ) however, certain Citrus flavonoids have an antimicrobial action against Phytophthora citrophthora (del Río et al, 2004 ). In the down-regulated dataset, GO terms associated with lignin synthesis via the phenylpropanoid pathway are over-represented.…”

The Top 10 oomycete pathogens in molecular plant pathology

“…Experimental plants, including Arabidopsis, Zea mays and Eucalyptus, for which comprehensive genomic information is available, are increasingly being used as host–pathogen platforms (for example, Allardyce et al ., ; Dempsey et al ., ; Rookes et al ., ). Fundamental studies on P. cinnamomi plant cell wall‐degrading enzymes and the genes that encode them are being undertaken (Hee et al ., ; Adrienne Hardham, Australian National University, Canberra, ACT, Australia, personal communication), as well as examination, at the molecular level, of defence pathways and their control (Eshraghi et al ., ; Gunning et al ., ).…”

Transcriptome analysis, using RNA‐Seq of Lomandra longifolia roots infected with Phytophthora cinnamomi reveals the complexity of the resistance response

“…), although in studies with the susceptible disease model plant Lupinus angustifolius, Gunning et al . () found that phosphite induced the production of a number of secondary metabolites that were correlated with lesion restriction and resistance to the pathogen. However, phosphite is not seen as a long‐term method to control disease as the pathogen may become resistant through the repeated use of phosphite, and toxicity has been reported in some plant species (Cahill et al .…”