Comparative genomics analysis unravels lineage-specific bursts of gene duplications related to the emergence of specialized pathways. The CYP76C subfamily of cytochrome P450 enzymes is specific to Brassicaceae. Two of its members were recently associated with monoterpenol metabolism. This prompted us to investigate the CYP76C subfamily genetic and functional diversification. Our study revealed high rates of CYP76C gene duplication and loss in Brassicaceae, suggesting the association of the CYP76C subfamily with species-specific adaptive functions. Gene differential expression and enzyme functional specialization in Arabidopsis thaliana, including metabolism of different monoterpenols and formation of different products, support this hypothesis. In addition to linalool metabolism, CYP76C1, CYP76C2, and CYP76C4 metabolized herbicides belonging to the class of phenylurea. Their ectopic expression in the whole plant conferred herbicide tolerance. CYP76Cs from A. thaliana. thus provide a first example of promiscuous cytochrome P450 enzymes endowing effective metabolism of both natural and xenobiotic compounds. Our data also suggest that the CYP76C gene family provides a suitable genetic background for a quick evolution of herbicide resistance.Although extensive monoterpenol (especially linalool) oxidative metabolism has been described in many plant species, leading to fragrant and bioactive compounds as diverse as alcohols, aldehydes, acids, and epoxides

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Fusarium verticillioides and F. graminearum cause ear rots in maize (Zea mays L.) that reduce yield and contaminate the grain with mycotoxins produced by the fungi. To map QTLs for resistance to these ear rots, a F 5 mapping population, consisting of 298 recombinant inbreds obtained by randomly selfing of the cross between LP4637 (moderately resistant) and L4674 (susceptible), was genotyped with 250 single nucleotide polymorphism markers and phenotyped 2 years for disease severity after silk inoculation with conidial suspensions of F. verticillioides and F. graminearum. Four QTLs were mapped in chromosomes 2, 3 and 5, bins 2.03, 3.05, 3.07 and 5.07, explaining ranges of 11.2-11.8, 3.4-5.1, 6.2-7.6 and 3.8-5.0 of phenotypic variances (%), respectively, depending on year and fungus. Additive effects of each QTL ranged from 5.0 to 11.9 % of ear area covered by mold and no epistatic interactions were observed. The four QTLs were effective for both Fusarium species and environments indicating that LP4637 is a source of broad resistance to Fusarium stable across environments. These results are consistent with previous research reporting QTLs for ear rot resistance in the same chromosome regions from sources of resistance growing in North America, Africa, Europe and China.