Systemic Induction of the Defensin and Phytoalexin Pisatin Pathways in Pea (Pisum sativum) against Aphanomyces euteiches by Acetylated and Nonacetylated Oligogalacturonides

• Published in: Molecules (Basel, Switzerland) Switzerland), 2017-06, Vol.22 (6), p.1017
• Main Authors: Selim, Sameh, Sanssené, Jean, Rossard, Stéphanie, Courtois, Josiane
• Format: Article
• Language: English
• Subjects: Acetylation; Aphanomyces - genetics; Aphanomyces euteiches; Defensins; Defensins - biosynthesis; Disease Resistance - genetics; Disease Resistance - immunology; Fungicides; Gene expression; Host-Pathogen Interactions - genetics; Host-Pathogen Interactions - immunology; Immune system; Infections; Inoculation; Life Sciences; Lignans; Mode of action; Oligogalacturonides; Oligosaccharides - metabolism; pea defense pathways; pea root rot; Phytoalexins; Pisatin; pisatins; Pisum sativum; Pisum sativum - genetics; Pisum sativum - immunology; Pisum sativum - metabolism; Pisum sativum - microbiology; Plant Diseases - genetics; Plant Diseases - immunology; Plant Diseases - microbiology; Plant Roots - metabolism; Plant Roots - microbiology; Polymerase chain reaction; Polymerization; real-time qPCR; Root rot; Sesquiterpenes - metabolism; Zoospores
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules22061017

Oligogalacturonides (OGs) are known for their powerful ability to stimulate the plant immune system but little is known about their mode of action in pea ( ). In the present study, we investigated the elicitor activity of two fractions of OGs, with polymerization degrees (DPs) of 2-25, in pea against . One fraction was nonacetylated (OGs - Ac) whereas the second one was 30% acetylated (OGs + Ac). OGs were applied by injecting the upper two rachises of the plants at three- and/or four-weeks-old. Five-week-old roots were inoculated with 10⁵ zoospores of . The root infection level was determined at 7, 10 and 14 days after inoculation using the quantitative real-time polymerase chain reaction (qPCR). Results showed significant root infection reductions namely 58, 45 and 48% in the plants treated with 80 µg OGs + Ac and 59, 56 and 65% with 200 µg of OGs - Ac. Gene expression results showed the upregulation of genes involved in the antifungal defensins, lignans and the phytoalexin pisatin pathways and a priming effect in the basal defense, SA and ROS gene markers as a response to OGs. The reduction of the efficient dose in OGs + Ac is suggesting that acetylation is necessary for some specific responses. Our work provides the first evidence for the potential of OGs in the defense induction in pea against root rot.