Purification of legumin-like proteins from Coffea arabica and Coffea racemosa seeds and their insecticidal properties toward cowpea weevil ( Callosobruchus maculatus ) (Coleoptera: Bruchidae).
Legumin-like proteins from seeds of Coffea arabica (CaL-1 and CaL-2) and Coffea racemosa (CrL-1 and CrL-2) were characterized and isolated by gel filtration and reverse-phase chromatography. The insecticidal properties of the purified proteins were tested against Callosobruchus maculatus using artificial diets. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analyses indicated that CaL-1 is composed of two subunits of 33 and 24 kDa, while CaL-2, CrL-1, and CrL-2 were monomeric with a single band of 14 kDa. The LD(50) values were 0.5% (w/w) for CaL-1 and 0.3% (w/w) for CaL-2, CrL-1, and CrL-2. ED(50) at 0.3% was assessed for all protein concentrations. The legumin-like proteins were not digested by midgut homogenates of C. maculatus until 8 h of incubation. CaL-1 and CaL-2 ( C. arabica ) and CrL-1 and CrL-2 ( C. racemosa ) are chitin-binding proteins, and their insecticidal properties toward C. maculatus larvae might be related to their capacity to bind chitin present in the larval gut and their associated low digestibility.
Coelho
Mirela Batista
MB
Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, CP 6109, 13083-970, Campinas, SP, Brazil.
Macedo
Maria Lígia Rodrigues
ML
Marangoni
Sérgio
S
Silva
Desiree Soares da
DS
Cesarino
Igor
I
Mazzafera
Paulo
P
D000818:Animals; D002846:Chromatography, Affinity; D002851:Chromatography, High Pressure Liquid; D003069:Coffee / Q000737:chemistry* / Q000196:embryology; D004591:Electrophoresis, Polyacrylamide Gel; D007306:Insecticides; D010940:Plant Proteins / Q000737:chemistry / Q000302:isolation & purification*; D012639:Seeds / Q000737:chemistry*; D048889:Weevils
D003069:Coffee; D007306:Insecticides; D010940:Plant Proteins