Author(s): Xie Yongli; Chen Gang; Gao Xuewen
Linked Author(s):
Keywords: Bacillus; Extreme environment; Molecular identification; Diversity analysis; Lipopeptide compound analysis
Abstract: Significant microbiological research applications have been undertaken into microbe resources in extreme environment in recent years. This exploratory study documents specific Bacillus strains with stress-resistant spore, isolated from the rhizosphere of plants found in unique enviro nmental conditions on the Qinghai-Tibetan Plateau, known as the third pole of the world. Based upon morphological classification, 29 isolates were chosen for phenotypic analysis and molecular identification methods, including ERIC-PCR and BOX-PCR fingerprints analysis, 16S rDNA and gyrB partial sequence analysis. Identified isolates included: Bacillus simplex (7 isolates), B. malacitensis (1 isolate), B. subtitles (4 isolates), B. megatherium (1 isolate), B. amyloliquefaciens (7 isolates), B. axarquiensis (1 isolate), B. atrophies (1 isolate), B. mojavensis (3 isolates) and Bacillus sp. (4 isolates). From these, 24 of the 29 Bacillus strains were screened with high antagonistic activity to Sclerotinia sclerotiorum and Xanthomonas oryzae pv. Using Oryzae in Bacillus for biocontrol applications could be suit in these stressful environmental conditions such as low-temperature, dry or salt-resistance. MALDI-TOF-MS analysis results showed that antagonistic strains could produced lipopeptide compounds such as fengycin, surfactin, iturinA, bacillomycins D, suggesting that the biocontrol efficacy of strains were probably related to the antifungal lipopeptide compounds produced by the strains themselves. The research provided biocontrol Bacillus resource for further developing and application of biofertilizer research adapting in the Qinghai-Tibet Plateau environment.
Year: 2013