Pipecolic Acid Is Induced in Barley upon Infection and Triggers Immune Responses Associated with Elevated Nitric Oxide Accumulation

• Published in: Molecular plant-microbe interactions Vol. 32; no. 10; pp. MPMI01190013R - 1313
• Main Authors: Lenk, Miriam, Wenig, Marion, Bauer, Kornelia, Hug, Florian, Knappe, Claudia, Lange, Birgit, Timsy, Häußler, Finni, Mengel, Felicitas, Dey, Sanjukta, Schäffner, Anton, Vlot, A Corina
• Format: Journal Article
• Language: English
• Published: United States American Phytopathological Society 01-10-2019
• Subjects: Accumulation; Acids; Airborne microorganisms; Barley; Exudates; Exudation; Fungi; Immune response; Immunity; Infections; Innate immunity; Inoculum; Leaves; Nitric oxide; Pathogens; Powdery mildew; Priming; Reactive oxygen species; Superoxide; pipecolic acid; priming; nitric oxide; systemic acquired resistance; plant immunity; reactive oxygen species
• ISSN: 0894-0282; 1943-7706
• DOI: 10.1094/MPMI-01-19-0013-R

Pipecolic acid (Pip) is an essential component of systemic acquired resistance, priming resistance in
against (hemi)biotrophic pathogens. Here, we studied the potential role of Pip in bacteria-induced systemic immunity in barley. Exudates of barley leaves infected with the systemic immunity-inducing pathogen
pv.
induced immune responses in
The same leaf exudates contained elevated Pip levels compared with those of mock-treated barley leaves. Exogenous application of Pip induced resistance in barley against the hemibiotrophic bacterial pathogen
pv.
. Furthermore, both a systemic immunity-inducing infection and exogenous application of Pip enhanced the resistance of barley against the biotrophic powdery mildew pathogen
f. sp.
. In contrast to a systemic immunity-inducing infection, Pip application did not influence lesion formation by a systemically applied inoculum of the necrotrophic fungus
. Nitric oxide (NO) levels in barley leaves increased after Pip application. Furthermore,
pv.
induced the accumulation of superoxide anion radicals and this response was stronger in Pip-pretreated compared with mock-pretreated plants. Thus, the data suggest that Pip induces barley innate immune responses by triggering NO and priming reactive oxygen species accumulation.