Chemical defenses in soybean leaves: solar ultraviolet-B radiation modulate defense induction by Anticarsia gemmatalis attack

DILLON, F; CHLUDIL, H; ZAVALA J.A.

Buenos Aires

Simposio; 32nd New Phytologist Symposium; 2013

New Phytologist

Although it is well known that solar ultraviolet B (UV-B) radiation enhances plant defenses, there is less knowledge about what traits  define insect resistance at field in crop systems, such as soybean. Here we study the effects of solar ultraviolet B (UV-B) radiation on: a) the modulation of phenolic compounds and trypsin inhibitors in soybean leaves b) survival, consumption and mass gainof Anticarsia gemmatalis larvae in filed conditions. Cultivar (cv.) Williams and cv. Charata were planted at field under two treatments generated by thick plastics: ambient UV-B and attenuated UV-B. Exclusion of solar UV-B radiation reduced   flavonoid content in leaves of both cultivars, but this reduction was more intense in cv. Charata than in Williams. Genistein (an isoflavonoid) derivates and trypsin proteases inhibitors were induced by A. gemmatalis attack in leaves, but with higher levels in those that received solar UV-B radiation. Survivorship, consumption and mass gain of larvae were significantly increased in larvae that fed on cv. Charata leaves with attenuated UV-B radiation, while this increase was less intense in cv. Williams. Our results suggest that solar UV-B radiation modulate plant resistance to A.gemmatalis in cv Charata, , probably because of changes in total flavonoids.