Solar UV-B radiation and ethylene play a key role in modulating effective defenses against herbivore insects in field-grown soybean.

ZAVALA J. A

Hangzhou

Congreso; The 10th Conference of Asia-Pacific Association of Chemical Ecologists.; 2019

APACE

Solar UV-B radiation has been reported to enhance plant defenses against herbivore insects in many species. However, the mechanism and traits involved in the UV-B mediated increment of plant resistance are largely unknown in crops species, such as soybean. Here we determined in undamaged and damaged leaves by Anticarsia gemmatalis larvae and in pods by stink bugs of two soybean cultivars (cv.) grown under attenuated or full solar UV-B radiation changes in jasmonates, ethylene, salicylic acid, trypsin protease inhibitor activity, flavonoids and mRNA expression of genes related with defenses. Ethylene emission induced by herbivory was synergistically increased in plants grown under solar UV-B radiation and was positively correlated with malonyl genistin concentration, TPI activity and expression of IFS2 and the defensive protein PR2, while was negatively correlated with leaf consumption and stink bug damage. The precursor of ethylene ACC applied exogenously to soybean was enough to strongly induce leaf isoflavonoids. Our results showed that in field-grown soybean isoflavonoids were regulated by both herbivory and solar UV-B inducible ET, while flavonols were regulated by solar UV-B radiation and not by herbivory or ET. Our study suggests that although ET can modulate UV-B-mediated priming of inducible plant defenses, some plant defenses, such as isoflavonoids are regulated by ET alone.