Abstract Maize(Zea mays L.) is the crop that has the highest area and yield in China since 2012. The incidence and prevalence of corn diseases affecting maize yield, especially southern corn rust and rough dwarf disease which broadly distribute southeast of China and Huanghuaihai maize zone, cause great losses. It is important to use the resistant germplasms for maize breeding. The bacterial arti?cial chromosome (BAC) cloning system is an invaluable tool in the cloning of disease resistance genes and in conducting structural and functional analyses. A BAC library for Qi319, the key source for disease-resistant maize breeding in China, was constructed in this study. Based on the modifications consisted of using etiolated cotyledon from 7 to 9 d growing plants as the DNA preparation source and addition of PVP-40 and β-mercaptoethanol in the extraction-washing buffer, we used 100 to 200 kb partial digested DNA fragments for 233 transformations. The fragments were ligated into CopyControl pCC1. The library contains 270 720 clones with an average insert size of 90 kb. Up to 1.33% of clones had no insert. Based on a haploid genome size of 2 300 Mb, the coverage of the library is about 10.43 genome equivalents, providing 99.99% possibility to isolate any maize gene or sequence in the library. No visible changes from the EcoRⅠ restriction patterns of four BAC clones between 20 and 100 generations indicated the stability of the BACs. In the future, the BAC library will serve as both a giant gene resource and an invaluable tool for map-based gene isolation, physical mapping and comparative genome analysis.
Xiu-Qing Zhang. Construction and Characterization of a Bacterial Arti?cial Chromosome Library of Maize(Zea mays L.) Inbred Line Qi319[J]. , 2013, 21(11): 1389-1395.
