title: A fungal insecticide engineered for fast per os killing of caterpillars has high field efficacy and safety in full-season control of cabbage insect pests.
abstract: Fungal insecticides developed from filamentous pathogens of insects are notorious for their slow killing action through cuticle penetration, depressing commercial interest and practical application. Genetic engineering may accelerate their killing action but cause ecological risk. Here we show that a Beauveria bassiana formulation, HV8 (BbHV8), engineered for fast per os killing of caterpillars by an insect midgut-acting toxin (Vip3Aa1) overexpressed in conidia has both high field efficacy and safety in full-season protection of cabbage from the damage of an insect pest complex dominated by Pieris rapae larvae, followed by Plutella xylostella larvae and aphids. In two fields repeatedly sprayed during summer, BbHV8 resulted in overall mean efficacies of killing of 71% and 75%, which were similar or close to the 70% and 83% efficacies achieved by commercially recommended emamectin benzoate but much higher than the 31% and 48% efficacies achieved by the same formulation of the parental wild-type strain (WT). Both BbHV8 and WT sprays exerted no adverse effect on a nontarget spider community during the trials, and the sprays did not influence saprophytic fungi in soil samples taken from the field plots during 4 months after the last spray. Strikingly, BbHV8 and the WT showed low fitness when they were released into the environment because both were decreasingly recovered from the field lacking native B. bassiana strains (undetectable 5 months after the spray), and the recovered isolates became much less tolerant to high temperature and UV-B irradiation. Our results highlight for the first time that a rationally engineered fungal insecticide can compete with a chemical counterpart to combat insect pests at an affordable cost and with low ecological risk.
authors: Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China.
authors: Yong-Jie
authors: YJ
authors: Liu
authors: Jing
authors: J
authors: Liu
authors: Sheng-Hua
authors: SH
authors: Ying
authors: Shu-Sheng
authors: SS
authors: Liu
authors: Ming-Guang
authors: MG
authors: Feng
mesh_terms: D000818:Animals; D052982:Beauveria / Q000235:genetics / Q000378:metabolism*; D001937:Brassica / Q000469:parasitology*; D005658:Fungi / Q000378:metabolism*; D007306:Insecticides / Q000378:metabolism / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects; D007915:Lepidoptera / Q000187:drug effects*; D009183:Mycotoxins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D010572:Pest Control, Biological / Q000379:methods; D012621:Seasons; D016019:Survival Analysis
chemical_list: D007306:Insecticides; D009183:Mycotoxins
references: J Invertebr Pathol. 2012 Jan;109(1):105-9
references: 22024554
references: Appl Environ Microbiol. 2010 Jul;76(14):4611-8
references: 20495052
references: Biotechnol Lett. 2006 Jun;28(11):799-804
references: 16786244
references: Mycopathologia. 2009 Sep;168(3):145-52
references: 19390989
references: Nat Biotechnol. 2007 Dec;25(12):1455-6
references: 17994009
references: Proc Natl Acad Sci U S A. 2011 Dec 20;108(51):20449-54
references: 22143757
references: Poult Sci. 2005 Mar;84(3):503-12
references: 15782922
references: Nat Biotechnol. 2005 Jan;23(1):57-62
references: 15637622
references: Appl Environ Microbiol. 2005 Jan;71(1):363-70
references: 15640210
references: Mycol Res. 2009 Jan;113(Pt 1):93-9
references: 18804165
references: Food Chem Toxicol. 2007 Jul;45(7):1179-85
references: 17320261
references: J Invertebr Pathol. 2009 Oct;102(2):155-9
references: 19666027
references: PLoS One. 2012;7(8):e43069
references: 22912789
references: Appl Microbiol Biotechnol. 2008 Dec;81(3):515-22
references: 18800183
references: Proc Natl Acad Sci U S A. 1996 Jun 25;93(13):6349-54
references: 8692818
references: J Invertebr Pathol. 2008 Oct;99(2):220-6
references: 18597773
references: Science. 2011 Feb 25;331(6020):1074-7
references: 21350178
references: Appl Environ Microbiol. 2007 Jan;73(1):295-302
references: 17085713
references: Appl Microbiol Biotechnol. 2010 May;86(5):1543-53
references: 20094711
references: Microb Biotechnol. 2013 Jan;6(1):27-35
references: 22639846