Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu, China.
The Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, Sericultural Research Institute, Chinese Academy of Agricultural Science, Zhenjiang, Jiangsu, China.
Arch Insect Biochem Physiol. 2020 May;104(1):e21663. doi: 10.1002/arch.21663. Epub 2020 Feb 19.
The life cycle of the holometabolous insect Bombyx mori (Linnaeus) consists of the embryo, larva, pupa, and adult stages with six larval molts. Ecdysone and juvenile hormones play important roles in the growth and development of the silkworms. The a42 silkworm mutant is recessive and homozygous lethal by exhibiting a dark-colored and small body size and fails to molt to second instar. We compared the gene expression of a42 mutants with normal individuals at the first larval molting stage to elucidate the physiological influence of the a42 mutation on the growth and development of silkworms. The transcriptomic sequencing results revealed that 1,411 genes are differentially expressed in a42 mutants, compared with wild-type control silkworms, in which 791 genes are upregulated and 620 genes are downregulated. Gene Ontology/Kyoto Encyclopedia of Genes and Genomes analyses identified differentially expressed genes (DEGs) assigned to biological pathways, such as pentose and glucoronate interconversions, glycerolipid metabolism, folate biosynthesis, amino sugar, and nucleotide sugar metabolism. Two hydroxylases of phenylalanine hydroxylase (BmPAH) and tyrosine hydroxylase (BmTh) are upregulated in a42 mutants. The influence of a42 mutation on these DEGs reveals that melanin metabolism plays an important role during the molting process in silkworms.
家蚕（Linnaeus）的完全变态生命周期包括胚胎、幼虫、蛹和成虫阶段，经历 6 次蜕皮。蜕皮激素和保幼激素在家蚕的生长发育中发挥着重要作用。a42 家蚕突变体是隐性纯合致死的，表现为体色深、体型小，无法蜕皮到 2 龄期。我们比较了 a42 突变体和正常个体在第一次幼虫蜕皮阶段的基因表达，以阐明 a42 突变对家蚕生长发育的生理影响。转录组测序结果表明，与野生型对照家蚕相比，a42 突变体中有 1411 个基因差异表达，其中 791 个基因上调，620 个基因下调。基因本体/京都基因与基因组百科全书分析确定了差异表达基因（DEGs）分配到生物途径，如戊糖和葡糖醛酸相互转化、甘油脂代谢、叶酸生物合成、氨基糖和核苷酸糖代谢。苯丙氨酸羟化酶（BmPAH）和酪氨酸羟化酶（BmTh）的两个羟化酶在 a42 突变体中上调。a42 突变对这些 DEGs 的影响表明，黑色素代谢在家蚕蜕皮过程中起着重要作用。
