Biological and molecular characterization of silkworm strains from the Brazilian germplasm bank of Bombyx mori

Abstract

ABSTRACT. Brazil has only one public genetic pool of Bombyx mori strains, which was established in 2005 at Universidade Estadual de Maringá, Maringá, Paraná State. This genetic bank has been maintained, and the strains have been characterized using genetic and morphological tools. The quantitative and qualitative traits, directly or indirectly related to productivity, were evaluated in 14 silkworm strains. In addition to biological and productivity analyses, DNA markers related to susceptibility to the B. mori nucleopolyhedrovirus (BmNPV) were analyzed. BmNPV is a major cause of production loss and is a serious problem for Paraná sericulture. The silkworm strains from diverse geographic origins were found to have different characteristics, including body weight, larval stage duration, cocoon weight, and other biological traits. In terms of productivity, the raw silk percentages were almost uniform, with an overall average of 16.28%. Overall, the Chinese strain C37 gave the best performance in many of the quantitative traits, and it surpassed the other strains in productivity Genetic characterization of Brazilian B. mori germplasm bank traits. Therefore, it can be used as one of the strains that compose the elite germplasm for silkworm breeding programs. Additionally, genetic molecular markers were efficient in discriminating between B. mori strains that had been identified based on their geographical origin. We found that all Japanese strains produced a 400-bp molecular marker that has been associated with susceptibility to BmNPV.

Low Genetic Polymorphism at the Cytochrome C Oxidase I in Silkworm Strains of the Brazilian Germplasm Bank

“…It was possible to characterize these strains into three distinct groups. More recently, [4] evaluated and characterized 14 Chinese and Japanese strains (AS3, AS31, C75, C36, C37, E8, F6, JK, M8, M11-2, M18, M11, B82 and B106) of UBGB based on several biological and productive characters. Furthermore, the use of molecular data (RAPD) allowed the characterization of the strains, dividing them into three groups according to their geographical origin.…”

“…Despite external morphological aspects of larvae and silk moths are often very similar among silkworm strains, B. mori strains have been described based on morphological, biological and/or productive characteristics [2]- [4]. However, these characteristics are highly variable and influenced by the environment.…”

Implications of genetic diversity in the improvement of silkworm Bombyx mori L.

“…Regarding the specific use of markers, Moorthy et al (2013) indicate that RAPD can discriminate and differentiate between B. mori breeds depending on the silk content and that using voltinism characteristics would allow the identification, conservation and subsequent use in improving performance and maximizing productivity in breeding programs. Pereira et al (2013) meanwhile assert that analysis with RAPD has proved to be an efficient technique for detecting variability and can further be used to identify materials susceptible to the BmNPV baculovirus. Elsewhere, Awasthi et al (2008) state that specific primers, such as RFLP and sequence-tagged sites (STS), and non-specific primers, such as RAPD and ISSR, can be used effectively to decipher genetic relationship problems in both improved populations and B. mori mutants.…”

Detection of Contamination and Analysis of Vertical Transmission of BmNPV in Eggs and Moths of <i>Bombyx mori</i>

“…Genomic DNA of six female moths, of each strain, was isolated according to [17]. After isolation, DNA was purified with phenol and chloroform (1:1) and precipitated with 2 volumes of ethanol.…”