The differential accumulation of endogenous flavonoids was recorded in soybean (G. max (L.) Merr. cv. “Nam Dan”) under infestation of cowpea aphid (Aphis craccivora Koch) and/or treatment of the crude extract of cyanobacterium strain Nostoc calcicola HN9-1a. During A. craccivora infestation, flavonoids in the aphid-infested leaves were strongly induced to high contents, which were – - fold higher than that observed in control. | Journal of Science and Technology 54 (2C) (2016) 271-277 ACCUMULATION OF FLAVONOIDS IN SOYBEAN UNDER EFFECTS OF CYANOBACTERIAL CRUDE EXTRACT AND APHID INFESTATION Mai Van Chung1, *, Doan Manh Dung2, Do Ngoc Dai3 1 2 Vinh University, 182 Le Duan, Vinh city, Nghe An province Hue University of Science, 77Nguyen Hue, Hue city, Thua Thien Hue province 3 Nghe An College of Economics, 51 Ly Tu Trong, Vinh city, Nghe An province * Email: Received: 15 June 2016; Accepted for publication: 15 October 2016 ABSTRACT The differential accumulation of endogenous flavonoids was recorded in soybean (G. max (L.) Merr. cv. “Nam Dan”) under infestation of cowpea aphid (Aphis craccivora Koch) and/or treatment of the crude extract of cyanobacterium strain Nostoc calcicola HN9-1a. During A. craccivora infestation, flavonoids in the aphid-infested leaves were strongly induced to high contents, which were – - fold higher than that observed in control. Those bioactive substances were suppressed by the single treatment of N. calcicola crude extract, however, were enhanced by the cross-talk interactions of N. calcicola HN9-1a and A. craccivora. Flavonoids in the double factors-effected soybean leaves were remarkably increased to high level since 24 hours after cowpea aphid attack, having by - higher than that in control. It was the important evidences to suggest that flavonoids may function in the defense mechanism of soybean “Nam Dan” against A. craccivora; and N. cacicola HN9-1a crude extract improved the accumulation of flavonoids in soybean response to cowpea aphid infestation. Keywords: flavonoids, cyanobacteria, soybean “Nam Dan”, cowpea aphid. 1. INTRODUCTION Cyanobacteria are known to produce various kinds of bioactive compounds that affect many physiological processes within living cells. Species belonging to genus Nostoc are regarded as good candidate for producing secondary substances that influence the growth of plants [1]. A large
