Herbivore perception decreases photosynthetic carbon assimilation and reduces stomatal conductance by engaging 12-oxo-phytodienoic acid, mitogen-activated protein kinase 4 and cytokinin perception.

ZAVALA, J. A.; MELDAU, S; MEZA-CANALES ID; BALDWIN IT

PLANT, CELL AND ENVIRONMENT (PRINT)

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2017 vol. 40 p. 1039 - 1056

0140-7791

Herbivory-induced changes in photosynthesis have been documented inmany plant species, however the complexity of photosynthetic regulationand analysis has thwarted progress in understanding the mechanisminvolved, particularly those elicited by herbivore-specific elicitors. Here weanalyzed the early photosynthetic gas-exchange responses in Nicotianaattenuata plants after wounding and elicitation with Manduca sexta oralsecretions,and the pathways regulating these responses. Elicitation withM. sexta oral-secretions rapidly decreased photosynthetic carbonassimilation(AC) in treated and systemic (untreated, vascularly connected)leaves, which were associated with changes in stomatal conductance,rather than with changes in Rubisco activity and RuBP-turnover.Phytohormone profiling and gas-exchange-analysis of oral-secretionelicitedtransgenic plants altered in phytohormone regulation, biosynthesisand perception, combined with micrografting techniques, revealed that thelocal photosynthetic-responses were mediated by 12-oxo-phytodienoic acid(OPDA), while the systemic responses involved interactions amongjasmonates, cytokinins and abscisic acid signaling mediated by mitogenactivated protein kinase 4 (MPK4). The analysis also revealed a role forcytokinins interacting with MPK4 in CO 2-mediated stomatal regulation.Hence oral-secretions, while eliciting jasmonic acid-mediated defenseresponses, also elicits OPDA-mediated changes in stomatal conductanceand Ac, an observation illustrating the complexity and economy of thesignaling that regulates defense and carbon assimilation pathways in response to herbivore attack.