Sensitive and rapid detection of the insect pathogenic fungus Metarhizium anisopliae var. anisopliae by loop-mediated isothermal amplification.

A set of six specific primers was designed by targeting intergenic spacer region (IGS) sequences. With Bst DNA polymerase, the products could be clearly amplified for 60 min at 62 °C in a simple water bath. The sensitivity of the loop-mediated isothermal amplification (LAMP) for detecting Metarhizium anisopliae var. anisopliae was about 0.01 pg fungal DNA per reaction (equivalent to 27 conidia). LAMP products could be judged with agar gel or naked eye after addition of SYBR Green I. There were no cross reactions with other fungal isolates indicating high specificity of the LAMP. The LAMP could detect the presence of M. anisopliae var. anisopliae from soil. The detection limits for M. anisopliae var. anisopliae of LAMP reaction was 50 conidia per reaction in soil.