Microbiologie médicale et diagnostic

Comparison study on host plant growth promotion by different Metarhizium species

Abstract

Xinggang Liao, Zebin Meng and Yanfen Huang

Metarhizium spp. is a kind of important entomopathogenic fungi, which has been widely applied as biological control agents in China and rest of the world. Besides killing target insects, these fungi could also survive in soils in natural environment. Partial strains could even colonize host plant root during saprophytic phase and some of them are able to promote host plants growth. Here, we tested the rhizosphere competence among different Metarhizium species (M. robertsii - Mr2575, Mr23 and Mr1046, M. anisopliae - Ma808, Ma932 and Ma939, M. brunneum - Mb820, Mb1187 and Mb2974 and M. acridum - Mac324) and their effects on corn growth, which is one of the primary cereal crops in Guizhou province. All strains colonized corn roots but Mb1187 and Mac324 had less rhizospheric populations than other strains during the one-month pot trial. In addition, Mb1187 and Mac324 failed to promote corn growth possibly due to their poor rhizosphere competence. In contrast, rhizospheric populations and growth promotion by rest of the strains were significantly increased. The Mr23, Ma939 and Mb820 strains demonstrated maximal increase in corn vegetative growth such as leaf collar formation and stalk growth, and thereafter were selected as qualified candidates for further virulence test on some indigenous underground pests.