Fatty Acid Desaturase Bmdesat5, Suppressed in the Salivary Glands by Domestication, is Involved in Regulation of Food Intake in Silkworms.

Understanding the evolutionary genetics of food intake regulation in domesticated animals has relevance to evolutionary biology, animal improvement, and obesity treatment. Here, we observed that the fatty acid desaturase gene (Bmdesat5), which regulates food intake, is suppressed in domesticated silkworms, but expressed in the salivary glands of the wild silkworm Bombyx mandarina. The content of its catalytic product, cis-vaccenic acid, was related to the expression levels of Bmdesat5 in the salivary glands of domesticated and wild silkworm strains. These two strains also showed significant differences in food intake. Using orally administering cis-vaccenic acid and transgenic-mediated overexpression, we verified that cis-vaccenic acid functions as a satiation signal, regulating food intake and growth in silkworms. Selection analysis showed that Bmdesat5 experienced selection, especially in the potential promoter, 5'-untranslated, and intron regions. This study highlights the importance of the decrement of satiety in silkworm domestication and provides new insights into the potential involvement of salivary glands in the regulation of satiety in animals, by acting as a supplement to gut-brain nutrient signaling.

Genome-wide identification and expression analysis of the growth regulating factor (GRF) family in Jatropha curcas.

GRF genes have been confirmed to have important regulatory functions in plant growth, development and response to abiotic stress. Although the genome of Jatropha curcas is sequenced, knowledge about the identification of the species' GRF genes and their expression patterns is still lacking. In this study, we characterized the 10 JcGRF genes. A detailed investigation into the physic nut GRF gene family is performed, including analysis of the exon-intron structure, conserved domains, conserved motifs, phylogeny, chromosomal locations, potential small RNA targets and expression profiles under both normal growth and abiotic stress conditions. Phylogenetic analysis indicated that the 10 JcGRF genes were classified into five groups corresponding to group I, II, III, IV and V. The analysis of conserved domains showed that the motifs of JcGRF genes were highly conserved in Jatropha curcas. Expression analysis based on RNA-seq and qRT-PCR showed that almost all JcGRF genes had the highest expression in seeds, but very low expression was detected in the non-seed tissues tested, and four JcGRF genes responded to at least one abiotic stress at at least one treatment point. Our research will provide an important scientific basis for further research on the potential functions of JcGRF genes in Jatropha curcas growth and development, and response to abiotic stress, and will eventually provide candidate genes for the breeding of Jatropha curcas.