Chen Keping

Progress in understanding resistance of Bombyx mori to nucleopolyhedrovirus

Bombyx mori nucleopolyhedrovirus (BmNPV) causes an important viral infectious disease in sericulture, and is responsible for 60% of the total cocoon production loss caused by various silkworm diseases. Horizontal resistance of silkworms to BmNPV is well known but we have identified a local line, named NB, whose LD50 is more than 1000 times higher than that of susceptible strains, and that has the highest resistance to BmNPV out of 344 silkworm lines. Through 10 years of crossbreeding and systematic selective breeding using line NB, we have constructed a commercial variety of Bombyx mori that is highly resistant to BmNPV. These genetic studies indicate the existence of BmNPV resistance genes in silkworm, and a pair of dominant genes has been implicated. Recently, we constructed a BmNPV-resistant near-isogenic line (NIL) via interspecific hybridization and backcrossing. Using this model and molecular techniques, such as fluorescent differential display-PCR, suppression subtractive hybridization, DNA microarray and proteomic analyses, we have identified molecules involved in BmNPV resistance. This review summarizes the current research status of BmNPV resistance in silkworms and discusses molecules involved in anti-BmNPV processes.