Nitrogen deficiency increases volicitin-induced volatile emission, jasmonic acid accumulation, and ethylene sensitivity in maize.
Insect herbivore-induced plant volatile emission and the subsequent attraction of natural enemies is facilitated by fatty acid-amino acid conjugate (FAC) elicitors, such as volicitin [N-(17-hydroxylinolenoyl)-L-glutamine], present in caterpillar oral secretions. Insect-induced jasmonic acid (JA) and ethylene (E) are believed to mediate the magnitude of this variable response. In maize (Zea mays) seedlings, we examined the interaction of volicitin, JA, and E on the induction of volatile emission at different levels of nitrogen (N) availability that are known to influence E sensitivity. N availability and volicitin-induced sesquiterpene emission are inversely related as maximal responses were elicited in N-deficient plants. Plants with low N availability demonstrated similar volatile responses to volicitin (1 nmol plant(-1)) and JA (100 nmol plant(-1)). In contrast, plants with medium N availability released much lower amounts of volicitin-induced sesquiterpenes compared with JA, suggesting an alteration in volicitin-induced JA levels. As predicted, low N plants exhibited greater sustained increases in wound- and volicitin-induced JA levels compared with medium N plants. N availability also altered volicitin-E interactions. In low N plants, E synergized volicitin-induced sesquiterpene and indole emission 4- to 12-fold, with significant interactions first detected at 10 nL L(-1) E. Medium N plants demonstrated greatly reduced volicitin-E interactions. Volicitin-induced sesquiterpene emission was increased by E and was decreased by pretreatment the E perception inhibitor 1-methylcyclopropene without alteration in volicitin-induced JA levels. N availability influences plant responses to insect-derived elicitors through changes in E sensitivity and E-independent JA kinetics.
Schmelz
Eric A
EA
Center of Medical, Agricultural, and Veterinary Entomology, U.S. Department of Agriculture, Agricultural Research Service, Gainesville, FL 32608, USA. eschmelz@gainesville.usda.ufl.edu
Alborn
Hans T
HT
Engelberth
Juergen
J
Tumlinson
James H
JH
D000818:Animals; D003517:Cyclopentanes / Q000378:metabolism*; D005030:Ethylenes / Q000494:pharmacology*; D005973:Glutamine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D007113:Immunity, Innate; D007313:Insecta / Q000254:growth & development; D009584:Nitrogen / Q000172:deficiency / Q000494:pharmacology*; D054883:Oxylipins; D010935:Plant Diseases / Q000469:parasitology; D012717:Sesquiterpenes / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013314:Stress, Mechanical; D014835:Volatilization / Q000187:drug effects; D003313:Zea mays / Q000187:drug effects / Q000378:metabolism* / Q000469:parasitology; D017962:alpha-Linolenic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology*
D003517:Cyclopentanes; D005030:Ethylenes; D054883:Oxylipins; D012717:Sesquiterpenes; C419781:volicitin; D017962:alpha-Linolenic Acid; D005973:Glutamine; C011006:jasmonic acid; C036216:ethylene; D009584:Nitrogen