Rubisco Evolution in C4 Eudicots: An Analysis of Amaranthaceae Sensu Lato

摘要: BACKGROUND: Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase) catalyses the key reaction in photosynthetic assimilation of CO₂. In C₄ plants CO₂ is supplied to by an auxiliary CO₂-concentrating pathway that helps maximize carboxylase activity enzyme while suppressing its oxygenase activity. As a consequence, exhibits higher maximum velocity but lower substrate specificity compared with C₃ enzyme. Specific amino-acids are associated photosynthesis monocots, it not known whether selection has acted on similar way eudicots. METHODOLOGY/PRINCIPAL FINDINGS: We investigated evolution Amaranthaceae sensu lato (including Chenopodiaceae), third-largest family plants, using phylogeny-based likelihood and Bayesian methods detect Darwinian chloroplast rbcL gene sample 179 species. Two residues, 281 309, were found be under positive multiple parallel replacements alanine serine at position methionine isoleucine 309. Remarkably, both have been detected other plant groups, such as illustrating striking parallelism molecular evolution. CONCLUSIONS/SIGNIFICANCE: Our findings illustrate how simple genetic changes can contribute strengthen hypothesis amino-acid adaptive Rubisco.