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Abstract The incidence and prevalence of corn disease are limiting factors, which can cause the decrease of corn yield. The maize(Zea mays L.) bacterial spot disease is currently one of potentially harmful diseases in China, has made some progress in the inheritance of resistance genes and chromosomal localization researches, but the progress in gene cloning and function identification researches is relatively slow. At present, using constructed fosmid library to clone the resistance candidate genes is one of efficient and effective methods. The construction of a genomic fosmid library of maize and screening of 2 receptor-like kinase genes (Psy1 and Psy2) were described in this study. The constructed maize fosmid library contained 3.7 × 105 clones, with an average inserts size of 32 kb, achieving the coverage probability of 4.73 fold maize genome, and screening probability of any gene or sequence reached 99.12%. Subsequently, using different primer combinations screening the library, 14 positive clones were obtained, of which 4 clones contained the complete Psy2 gene and Psy1 gene partial fragment, and 3 clones contained the complete Psy1 gene. Two positive clones 13-12F-23 and 32-4A-6 were sequenced, and the results showed that 2 exogenous fragments, one was 10.0 kb DNA fragment and the other was 13.5 kb DNA fragment, were inserted into the promoter and intron of Psy1 gene, respectively. The 13.5 kb DNA fragment was Huck LTR retrotransposon, and the 10.0 kb DNA fragment was a complicated retrotransposon containing helitron transposable element. Nevertheless, there was still a full-length cDNA of Psy1 gene was amplified, indicating that these 2 types of retrotransposon insertion did not make the Psy1 gene inactivation. This study provides a feasible research approach for gene cloning and functional analysis of maize.
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Received: 26 March 2014
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