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Copyright of Journal of Nanjing Agricultural University / Nanjuing Nongye Daxue Xuebao is the property of Journal of Nanjing Agricultural University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Nanjing Agricultural University / Nanjuing Nongye Daxue Xuebao is the property of Journal of Nanjing Agricultural University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Objectives] The main purpose of this study is to screen the Bacillus spp. with high antimicrobial activity from the rhizosphere soil of Malaysia. The lipopeptides produced by the Bacillus strains were identified, and biocontrol activities of these strains were evaluated.[Methods] The analysis of antagonistic activity was used to screen the Bacillus spp. with strong antagonistic activities against Xanthomonas oryzae pv.oryzae or Sclerotinia sclerotiorum. The phylogenetic tree based on the sequences of 16S rDNA and gyrB gene was used to identify the isolated Bacillus spp. strains. The matrix-assisted laser desorption/ionization-time of fligh mass spectrometry(MALDI-TOF-MS)was used to analyze the lipopeptide compound produced by the isolated strains. The greenhouse expriments were performed to evaluate the biocontrol effect on rice bacterial leaf blight of Bacillus spp. strains.[Results] The results of antagonistic activities showed that six isolated Bacillus strains(D15, W3, Klu7, YM16, D1 and PLZ26)have significant inhibitory activities against Xanthomonas oryzae pv.oryzae or Sclerotinia sclerotiorum, and among these strains, D15 and W3 have inhibitory activities to both of them. Phylogenetic tree indicated that these six isolates were identified to be most closely related to Bacillus amyloliquefaciens(D15 and W3), B. pumilus(Klu7), B. cereus(YM16)and B. thuringiensis(D1 and PLZ26). Lipopeptide compound analysis via MALDI-TOF-MS showed that PLZ26 and Klu7 produced Surfactin, and strains D15 and W3 produced Iturin A. The evaluation of the biocontrol effect showed that PLZ26 has good control effect on bacterial blight of rice.[Conclusions] This study provided the bacterial resources for the research and exploitation of biopesticides. [ABSTRACT FROM AUTHOR]

[Objectives] In our previous study, two HrpZ proteins, HrpZpSgS1 and HrpZpsgA1, were identified from Pseudomonas syringae pv. glycinea A1 and S1 strains, and the HR elicitation activity of HrpZpsgs1 in tobacco was stronger than that of HrpZp5gA1- Compara­tive analysis of their amino sequences showed that three different regions mainly existed in C-terminal. In order to clarify the relation­ship of these differential regions of HrpZ proteins and the ability in eliciting the HR and disease resistance，we constructed 6 recom­binant proteins by respectively exchanging three differential regions between HrpZpsgs1 and HrpZp5gA1. [ Methods] After expression and purification，6 recombinant proteins about 41 x 103 were got，and HR elicition ability and Tobacco Mosaic Virus ( TMV) disease resistance ability were detected. [ Results] HrpZs(s2→A2) and HrpZA(A3→s3) could induce stronger HR in tobacco compared with the wild-type proteins，furthermore，all of 6 recombinant proteins could reduce the phenotype caused by inoculation with TMV better than wild-type proteins，and among them HrpZA(A3→s3) and HrpZs(s3-A3) showed the best effects. [ Conclutions] These results showed that the 7,8,9 a-helices were the main regulatory regions of HR，and thse 8,9 a-helices were also related to the disease resistance. This study provides the theoretical basis for molecular modification of HrpZ harpin protein in the future. [ABSTRACT FROM AUTHOR]