Metarhizium robertsii Produces an Extracellular Invertase (MrINV) That Plays a Pivotal Role in Rhizospheric Interactions and Root Colonization |
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| Authors: | Xinggang Liao Weiguo Fang Liangcai Lin Hsiao-Ling Lu Raymond J. St. Leger |
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| Affiliation: | 1. Department of Entomology, University of Maryland, College Park, Maryland, United States of America.; 2. Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China.; 3. Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.; Universidade de Sao Paulo, Brazil, |
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| Abstract: | ![]()
As well as killing pest insects, the rhizosphere competent insect-pathogenic fungus Metarhizium robertsii also boosts plant growth by providing nitrogenous nutrients and increasing resistance to plant pathogens. Plant roots secrete abundant nutrients but little is known about their utilization by Metarhizium spp. and the mechanistic basis of Metarhizium-plant associations. We report here that M. robertsii produces an extracellular invertase (MrInv) on plant roots. Deletion of MrInv (⊿MrInv) reduced M. robertsii growth on sucrose and rhizospheric exudates but increased colonization of Panicum virgatum and Arabidopsis thaliana roots. This could be accounted for by a reduction in carbon catabolite repression in ⊿MrInv increasing production of plant cell wall-degrading depolymerases. A non-rhizosphere competent scarab beetle specialist Metarhizium majus lacks invertase which suggests that rhizospheric competence may be related to the sugar metabolism of different Metarhizium species. |
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