Studies On Harpin Effervescent Tablet And Using It Control An New Corn Diseases

Harpin proteins that produced by Gram-negative plant pathogenic bacteria have elicitor function,its encoding genes is hrp gene cluster member.Meanwhile,Harpins have similar biological and physical characteristics,including rich in Glycine(Gly),not contain Cysteine(Cys),thermal stability and sensitive to protease.Harpin has a variety of beneficial biological effects such as insect resistance,disease resistance,drought resistance and promote plant growth.This study was to research the stability and biological activity of the Harpin proteins effervescent tablets,as well as control effect on new corn bacterial diseases.The rearch is to provide the foundation for the application of Harpin protein biological pesticide.In this experiment,Harpin is derived from recombination strain BL21/pET30a(+)-hrf2 that was induced expression by 0.1 mM IPTG.We obtained Harpin crude protein by breaking up of boiling water and ultrasonic disruption.We purified the crude protein derived from breaking up of ultrasonic disruption.After cryogenic freeze drying of Harpin crude protein and Harpin pure protein,we used a way of acid-base separation granulation tableting to make pure-protein Harpin effervescent tablets and crude-protein Harpin effervescent tablets.Through testing concentration and activity of pure-protein Harpin effervescent tablets and crude-protein Harpin effervescent tablets in three different periods.we found that the effect of pure-protein Hapin effervescent tablets are much less than crude-protein Harpin effervescent tablets.Why have this kind of phenomenon,we suspect that pure-protein Harpin effervescent tablets easily absorbing moisture and lead to protein degradation.So in later prevention and control effect tests,we only use the crude-protein Harpin effervescent tablets.For corn's good adaptability to the environment,corn has become the world's first big food crops.Corn is also widely distributed in our country,there are 31 national provinces and autonomous regions have corn,which play an increasingly important role in national economy.In this experiment,we collected three bacteria which were isolated from corn plant diseases in four areas in hebei(Wu Yi,Xianxian,fucheng and YongNian).According to the result of 16s rDNA matched they identified as Pantoea ananatis,Pantoea agglomerans and Pantoea dispersa.But according to the result of gyrB matched they identified as Pantoea ananatis and Pantoea dispersa.Meanwhile it has not reported that Pantoea dispersa can caused corn disease so far.According to the laws of Koch's validation,Pantoea ananatis and Pantoea dispersa collected from hebei are proved to be the pathogenic bacteria of corn disease.And greenhouse experiment found that Pantoea dispersa can cause more severe disease in corn than Pantoea ananatis.In order to control the new disease,we only studied the control effect of Pantoea dispersa by crude-protein effervescent tablets in this research.In Control effect experiment,we used water as control.The result shows that crude-protein Harpin effervescent tablets(50 ug/ml)have good control effect,which reached to 37.5%.