Induction, Purification And Antifungal Activity Of β-1,3-glucanase From Wheat

1,3-glucanase is an important matter in the antifiingi of plant.lt can be induced by many biofactors and nonbiofactors. ?-1,3-glucanase can inhibit the growth and reproduction of plant fungal pathogens. P -1, 3- glucanase can hydrolyze P -1,3-ghican and P -1,3-1,6-glucan of fungal cell walls,and the degrading products are a source of elicitors for plant systematic defense response.Treatment with mercuric chloride (0.01%), salicylic acid(10.0 u g/ m L)or riboflavin(l mmol/L)induced the P -1,3- glucanase activity in all the three wheat varieties i.e. 331, Kangdao 680 and Lumai 23 tested, with the strongest inductive effect on variety 331 by treatment with mercuric chloride (0.01%) for 24 h. From leaves of variety 331 treated with mercuric chloride (0.01%) for 24 h, a kind of P -1,3-glucanase was purified by fractional precipitation with ammonium sulphate, Phenyl-Sepharose chromatography (Phenyl-Sepharose Fast Flow), ion-exchange chromatography (DEAE-Sepharose Fast Flow), and gel- filtration chromatography (Sephacryl S-100).Through SDS-PAGE and gel filtration, the molecular weight of the purified P -1,3-glucanase was determined to be about 52.0-53.6 kD. The purified P'-1,3-glucanase showed antifungal activity against both Alternaria longipes and Rhizoctonia cerealis on tested plates,and inhibited the germ tube elongation and spore germination of Verticillium dahliae and Fusariwn omysporum f.sp. cucumerinum. P -1,3-glucanase has an optimum PH of 4.5~5.0 and an optimum temprature of 35 .Different metal ions show different effects on the P -1,3-glucanase acticity, Na2+. K.+ Ba2+ Mn2+ enhance activity, whereas Fe2+ Ag+. Cu3+ . Zn2+cause obvious inhibition.