Streptomyces-induced resistance against oak powdery mildew involves host plant responses in defense, photosynthesis, and secondary metabolism pathways.
Rhizobacteria are known to induce defense responses in plants without causing disease symptoms, resulting in increased resistance to plant pathogens. This study investigated how Streptomyces sp. strain AcH 505 suppressed oak powdery mildew infection in pedunculate oak, by analyzing RNA-Seq data from singly- and co-inoculated oaks. We found that this Streptomyces strain elicited a systemic defense response in oak that was, in part, enhanced upon pathogen challenge. In addition to induction of the jasmonic acid/ethylene-dependent pathway, the RNA-Seq data suggests the participation of the salicylic acid-dependent pathway. Transcripts related to tryptophan, phenylalanine, and phenylpropanoid biosynthesis were enriched and phenylalanine ammonia lyase activity increased, indicating that priming by Streptomyces spp. in pedunculate oak shares some determinants with the Pseudomonas-Arabidopsis system. Photosynthesis-related transcripts were depleted in response to powdery mildew infection, but AcH 505 alleviated this inhibition, which suggested there is a fitness benefit for primed plants upon pathogen challenge. This study offers novel insights into the mechanisms of priming by actinobacteria and highlights their capacity to activate plant defense responses in the absence of pathogen challenge.
Florence
F
Kurth
Sarah
S
Mailänder
Markus
M
Bönn
Lasse
L
Feldhahn
Sylvie
S
Herrmann
Ivo
I
Große
François
F
Buscot
Silvia D
SD
Schrey
Mika T
MT
Tarkka
D001203:Ascomycota / Q000472:pathogenicity*; D003517:Cyclopentanes / Q000378:metabolism; D005030:Ethylenes / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D063990:Gene Ontology; D059014:High-Throughput Nucleotide Sequencing; D054884:Host-Pathogen Interactions; D054883:Oxylipins / Q000378:metabolism; D010788:Photosynthesis; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology / Q000469:parasitology; D010937:Plant Growth Regulators / Q000378:metabolism; D057865:Plant Immunity; D018515:Plant Leaves / Q000276:immunology / Q000382:microbiology / Q000469:parasitology / Q000502:physiology; D018517:Plant Roots / Q000276:immunology / Q000382:microbiology / Q000469:parasitology / Q000502:physiology; D029963:Quercus / Q000276:immunology / Q000382:microbiology / Q000469:parasitology / Q000502:physiology*; D020156:Salicylic Acid / Q000378:metabolism; D064210:Secondary Metabolism; D017423:Sequence Analysis, RNA; D015398:Signal Transduction; D013302:Streptomyces / Q000502:physiology*
D003517:Cyclopentanes; D005030:Ethylenes; D054883:Oxylipins; D010937:Plant Growth Regulators; C011006:jasmonic acid; C036216:ethylene; D020156:Salicylic Acid