Plant defense responses to herbivores involve recognition of independent herbivore-associated molecular patterns in rice
T. SHINYA (1), Y. Hojo (2), Y. Desaki (3), J. Christeller (4), K. Okada (5), N. Shibuya (3), I. Galis (2) (1) Institute of Plant Science and Resources, Okayama University, Japan; (2) Institute of Plant Science and Resources, Okayama University, Japan; (3) Department of Life Sciences, Meiji University, Japan; (4) The New Zealand Institute for Plant & Food Research, New Zealand; (5) Biotechnology Research Center, The University of Tokyo, Japan

Wounding and/or perception of herbivore-associated molecular patterns (HAMPs) contained in their oral secretions (OS) and/or saliva trigger various defense responses against insect herbivores in plants. Elicitor activities of two OS types isolated from Mythimna loreyi (rice generalist herbivore) and Parnara guttata (specialist) insect larvae were directly compared in the current study. Both OS showed substantial elicitor activity in the rice cell system that was optimized and used for detection of early (accumulation of ROS) and late (accumulation of secondary metabolites) defense responses in rice. OS from M. loreyi contained large amounts of previously reported insect HAMPs known as fatty acid-amino acid conjugates (FACs). Interestingly, FACs were absent in the elicitor-active P. guttata’s OS, suggesting the presence of another yet unknown and FAC-independent elicitor. As one candidate, we identified a novel elicitor active high molecular mass fraction within the M. loreyi and P. guttata OS samples that were subjected to separation by dialysis. This novel elicitor strongly promoted both ROS and metabolite accumulations in rice cells, and its activity was further enhanced by FAC co-application. Our data suggest that plants may sense and integrate various independent signals to respond to herbivores under natural conditions.

Abstract Number: P17-610
Session Type: Poster