ZmGns,a maize class I β-1,3-glucanase,is induced by biotic stresses and possesses strong antimicrobial activity

Plant b-1,3-glucanases are members of the pathogenesis-related protein 2(PR-2) family,which is one of the 17 PR protein families and plays important roles in biotic and abiotic stress responses.One of the differentially expressed proteins(spot 842) identified in a recent proteomic comparison between five pairs of closely related maize(Zea mays L.) lines differing in aflatoxin resistance was further investigated in the present study.Here,the corresponding cDNA was cloned from maize and designated as ZmGns.ZmGns encodes a protein of338 amino acids containing a potential signal peptide.The expression of Zm Gns was detectible in all tissues studied with the highest level in silks.ZmGns was significantly induced by biotic stresses including three bacteria and the fungus Aspergillus flavus.ZmGns was also induced by most abiotic stresses tested and growth hormones including salicylic acid.In vivo,ZmGns showed a significant inhibitory activity against thebacterial pathogen Pseudomonas syringae pv.tomato DC3000 and fungal pathogen Botrytis cinerea when it overexpressed in Arabidopsis.Its high level of expression in the silk tissue and its induced expression by phytohormone treatment,as well as by bacterial and fungal infections,suggest it plays a complex role in maize growth,development,and defense.     

Selective Removal of Nitrogen from Quinoline and Petroleum by Pseudomonas ayucida IGTN9m

Enrichment culture experiments employing soil and water samples obtained from petroleum-contaminated environments succeeded in the isolation of a pure culture possessing the ability to utilize quinoline as a sole nitrogen source but did not utilize quinoline as a carbon source. This culture was identified as Pseudomonas ayucida based on a partial 16S rRNA gene sequence, and the strain was given the designation IGTN9m. Examination of metabolites using thin-layer chromatography and gas chromatography-mass spectrometry suggests that P. ayucida IGTN9m converts quinoline to 2-quinolinone and subsequently to 8-hydroxycoumarin. Resting cells of P. ayucida IGTN9m were shown to be capable of selectively removing about 68% of quinoline from shale oil in a 16-h treatment time. These results suggest that P. ayucida IGTN9m may be useful in petroleum biorefining for the selective removal of organically bound nitrogen from petroleum.