DEVELOPMENT OF ARBUSCULAR MYCORRHIZAL FUNGI IN THE PRESENCE OF DIFFERENT PATTERNS OF Trifolium repens SHOOT FLAVONOIDS

SCERVINO J.M; PONCE M.A.; DELLA MONICA I,; VIERHEILIG H.; OCAMPO J.A.; GODEAS A.

REVISTA DE LA CIENCIA DEL SUELO Y NUTRICIóN VEGETAL

SOC CHILENA CIENCIA SUELO

Año: 2009 p. 102 - 115

0717-635X

We tested the effects of the flavonoid 3-methoxi-5,6,7,8-hydroxy-4’hydroxy flavone(NMHTV) isolated from shoots of non arbuscular mycorrhizal (AM) inoculated clover,and of the flavonoids 5,6,7,8-hydroxy-3-methoxy flavone (MH-1); 5,6,7,8-hydroxy-4’-hydroxy flavone (MH-2); and 5,7-hydroxy-3,4’-methoxy flavone (MH-3); isolated fromAM clover (Trifolium repens) shoots, on spore germination, hyphal length, hyphalbranches and the number of cluster of auxiliary cells or the number of secondary spores(Presymbiotic stage) and on the number of entry points and the percentage of AMcolonized root of tomato (Lycopersicum esculentum) by the AM fungi Gigaspora rosea,Giaspora margarita, Glomus mosseae and Glomus intraradices (Symbiotic stage). Nonsignificant effects of the flavonoids isolated from the shoot of mycorrhizal colonizedclover on the presymbiotic and symbiotic stages of Gigaspora and Glomus endophyteswere found. The flavonoid NMHTV isolated from non AM clover shoot, did not affectthe percentage of germination of spores but significantly increased (P < 0.05) the othersteps of the presymbiotic stage of Gi. margarita spores when 2 μM concentration wasused. The symbiotic stage of Gi. margarita was also significantly increased when 2 μMof the flavonoid NMHTV was applied. This flavonoid had no effect on the presymbioticdevelopment of G. mosseae, G. intraradices and Gi. rosea except when 8 μMconcentration was used, which inhibited the hyphal length of Gi. rosea. These resultssuggest the possible implication of the flavonoid NMHTV in the susceptibility oftomato roots to the AM formation by Gi. margarita. The absence of stimulation of theAM presymbiotic and symbiotic stages in tomato by exogenous application of the newlysynthesized flavonoids MH-1, MH-2, and MH-3, in clover shoots after AMcolonization, indicated that the autorregulation of the AM symbiosis can be, at leastpartially, due to the disappearance of flavonoids in AM colonized plants that stimulatedthe AM symbiosis.