Differential effectiveness of microbially induced resistance against herbivorous insects in Arabidopsis.
Rhizobacteria-induced systemic resistance (ISR) and pathogen-induced systemic acquired resistance (SAR) have a broad, yet partly distinct, range of effectiveness against pathogenic microorganisms. Here, we investigated the effectiveness of ISR and SAR in Arabidopsis against the tissue-chewing insects Pieris rapae and Spodoptera exigua. Resistance against insects consists of direct defense, such as the production of toxins and feeding deterrents and indirect defense such as the production of plant volatiles that attract carnivorous enemies of the herbivores. Wind-tunnel experiments revealed that ISR and SAR did not affect herbivore-induced attraction of the parasitic wasp Cotesia rubecula (indirect defense). By contrast, ISR and SAR significantly reduced growth and development of the generalist herbivore S. exigua, although not that of the specialist P. rapae. This enhanced direct defense against S. exigua was associated with potentiated expression of the defense-related genes PDF1.2 and HEL. Expression profiling using a dedicated cDNA microarray revealed four additional, differentially primed genes in microbially induced S. exigua-challenged plants, three of which encode a lipid-transfer protein. Together, these results indicate that microbially induced plants are differentially primed for enhanced insect-responsive gene expression that is associated with increased direct defense against the generalist S. exigua but not against the specialist P. rapae.
Graduate School Experimental Plant Sciences, Section Plant-Microbe Interactions, Institute of Environmental Biology, Faculty of Science, Utrecht University, P.O. Box 800.56, 3508 TB Utrecht, The Netherlands.
Vivian R
VR
Van Oosten
Natacha
N
Bodenhausen
Philippe
P
Reymond
Johan A
JA
Van Pelt
L C
LC
Van Loon
Marcel
M
Dicke
Corné M J
CM
Pieterse
D000818:Animals; D017360:Arabidopsis / Q000235:genetics / Q000382:microbiology* / Q000469:parasitology* / Q000502:physiology; D003517:Cyclopentanes / Q000378:metabolism; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D054884:Host-Pathogen Interactions / Q000235:genetics / Q000502:physiology; D007313:Insecta / Q000472:pathogenicity*; D007915:Lepidoptera / Q000472:pathogenicity; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D054883:Oxylipins / Q000378:metabolism; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology / Q000469:parasitology; D030821:Plants, Genetically Modified; D011549:Pseudomonas / Q000235:genetics; D020156:Salicylic Acid / Q000378:metabolism; D015398:Signal Transduction; D018411:Spodoptera / Q000472:pathogenicity; D014863:Wasps / Q000472:pathogenicity
D003517:Cyclopentanes; D054883:Oxylipins; C011006:jasmonic acid; D020156:Salicylic Acid