基金Acknowledgments We wish to thank Prof GZ Zhang and Prof ZF Zhang at the Sericultural Research Institute of the Chinese Academy of Agricultural Sciences for B. mori strain and silkworm artificial diet, respectively. This work was supported by the National Natural Science Foundation of China (30670659, 30771086, 30721064), the Major State Basic Research Development Program of China (973 Program) (2006CB500700, 2006CB910700, 2010CB833705), and the National High Technology Research and Development Program of China (863 Program) (2006AA10A119).