Construction of Beauveria bassiana T-DNA insertion mutant collections and identification of thermosensitive and osmosensitive mutants

Abstract:

Abstract: [Objective] This study was to identify genes involved in thermotolerance and osmotolerance of Beauveria bassiana. [Methods] A collection of T-DNA random insertion mutagenesis was constructed and thermosensitive and osmosensitive mutants were screened. The DNA fragments flanking to inserted T-DNA sequence in the mutants were isolated by using Y-shaped adaptor dependent extension (YADE) method. [Results] Five mutants impaired in thermotolerance or osmotolerance were identified and characterized. Mutant 212 and 2550 could not grow at 32oC, while mutants 139, 2737 and 2812 showed depressed growth under osmotic stress. Conidial viabilities of 212 was decreased by 23%, 52% and 21% after stressed by ultraviolet, heat shock, and H2O2 oxidation, respectively, compared to the wild-type strain. Virulence of mutant 212 and 2737 against aphids Myzus persicae were reduced by 12% and 40%, respectively. Sequencing analysis indicated that two function-unknown genes were interrupted by insertion of T-DNA in mutant 212 and 2737. In other three mutants, the insertions are located in the non-encoding regions. [Conclusion] The results demonstrate the successful use of T-DNA insertion mutagenesis in identification of genes involved in thermotolerance and osmotolerance of B. bassiana.