Conidia play important roles in primary and secondary infections of airborne fungal pathogens. In this study, an insertional mutant with reduced capacity for conidiation was isolated from the rice blast fungus Magnaporthe oryzae. The mutant has a T-DNA insertion that disrupts a gene named MoCPS1. The deduced MoCps1 protein contains three AMP-binding domains. Gene complementation and gene knockout assays confirmed that MoCPS1 is important for conidiation. Conidia produced by the MoCPS1 deletion mutants are much more slender and longer than those produced by the wild-type strain. The Mocps1 mutants are less efficient in both appressorial penetration and invasive growth of infection hyphae, resulting in attenuated virulence toward host plants. MoCPS1 is highly expressed in a mature appressorium. Interestingly, the expression levels of several genes related to conidiation and pathogenicity have been significantly altered in the MoCPS1 deletion mutants. Taken together, our results indicated that MoCPS1 is important for conidiogenesis, conidial morphogenesis, and pathogenesis in the rice blast fungus.

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The formation of columbite-group mineral phases in peraluminous granite has not been demonstrated to date. Here, a nanoscale study of the columbite-tantalite mineral in the Zhaojinggou Nb-Ta deposit in North China Craton elucidated its formation mechanism and the role of fluids in Nb-Ta mineralization. Transmission electron microscopy (TEM) analysis of a focused ion beam cut of the columbite-tantalite mineral revealed a comparatively well-ordered mineral structure. Energy-dispersive X-ray spectroscopy (EDS) revealed the presence of Nb, Ta, Mn, W, Fe, Sn, and Pb in the columbite-tantalite mineral. Furthermore, detailed TEM images depicted the nanoscale hydrothermal fluid occurring within the columbite-group mineral grain as well as between columbite-tantalite mineral and quartz grains. K, Al, Si, and O were found to be enriched in the hydrothermal fluid that was present between the quartz grains and the columbite-tantalite mineral. It did not react with the mineral grains of the columbite group. The ultrastructure of the columbite-tantalite mineral suggested the columbite-group mineral in the Zhaojinggou Nb-Ta deposit formed during magmatic crystallization rather than from hydrothermal fluids. Furthermore, HR-TEM images provided the first nanoscale observations of the fluid-mediated mineral dissolution and amorphous phase formation. This study also revealed that the mineral dissolution, element transport, and reprecipitation were significantly influenced by the fluid amorphous phase in the Nb-Ta deposits.

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