0000000000697625
AUTHOR
Rosario Egil
The link between independent acquisition of intracellular gamma-endosymbionts and concerted evolution in Tremblaya princeps
Many insect species establish mutualistic symbiosis with intracellular bacteria that complement their unbalanced diets. The betaproteobacterium "Candidatus Tremblaya" maintains an ancient symbiosis with mealybugs (Hemiptera: Pseudococcidae), which are classified in subfamilies Phenacoccinae and Pseudococcinae. Most Phenacoccinae mealybugs have "Candidatus Tremblaya phenacola" as their unique endosymbiont, while most Pseudococcinae mealybugs show a nested symbiosis (a bacterial symbiont placed inside another one) where every "Candidatus Tremblaya princeps" cell harbors several cells of a gammaproteobacterium. Genomic characterization of the endosymbiotic consortium from Planococcus citri, co…
Small genomes and the difficulty to define minimal translation and metabolic machineries
The notion of minimal life has sparked the interest of scientists in different fields, ranging from the origin-of-life research to biotechnology-oriented synthetic biology. Whether the interest is focused on the emergence of protocells out of prebiotic systems or the design of a cell chassis ready to incorporate new devices and functions, proposing minimal combinations of genes for life is not a trivial task. Using comparative genomics and biochemistry of endosymbionts (i.e., intracellular mutualistic symbionts) and intracellular parasites, a decade ago we proposed the core of a minimal gene set for a simple heterotrophic cell adapted to a chemically complex environment. In this work, we di…
Molecular evidence for ongoing complementarity and horizontal gene transfer in endosymbiotic systems of mealybugs
[EN] Intracellular bacterial supply of essential amino acids is common among sap-feeding insects, thus complementing the scarcity of nitrogenous compounds in plant phloem. This is also the role of the two mealybug endosymbiotic systems whose genomes have been sequenced. In the nested endosymbiotic system from Planococcus citri (Pseudococcinae), “Candidatus Tremblaya princeps” and “Candidatus Moranella endobia” cooperate to synthesize essential amino acids, while in Phenacoccus avenae (Phenacoccinae) this function is performed by its single endosymbiont “Candidatus Tremblaya phenacola.” However, little is known regarding the evolution of essential amino acid supplementation strategies in oth…