The Evolutionary Basis of Translational Accuracy in Plants

Area of Science:

• Evolutionary biology
• Molecular biology
• Genetics

Background:

• Mistranslation errors in protein synthesis reduce organismal fitness by producing nonfunctional proteins.
• Natural selection acts to minimize these errors, particularly at critical sites for protein structure and function, by selecting for accurately translated codons.

Purpose of the Study:

• To investigate the factors driving selection for translational accuracy in plant genes across different clades.
• To understand how synonymous codon bias and its underlying determinants vary among Brassicaceae, Fabidae, and Poaceae.

Main Methods:

• Analysis of synonymous codon bias at evolutionarily conserved sites in plant genes.
• Examination of the correlation between codon bias and tRNA abundance.
• Investigation of the influence of protein domains and mRNA secondary structures on codon choice and translational accuracy.

Main Results:

• Signatures of translational selection were observed across diverse plant species, but the contributing factors differed in nature and intensity.
• Synonymous codon bias varied among plant clades but was uniform within clades, with little correlation to tRNA abundance.
• Codon choice was influenced by site-specific selection pressure, protein domain participation, and mRNA secondary structures, with distinct impacts across plant clades.

Conclusions:

• Factors beyond tRNA pools significantly influence codon choice and translational accuracy in plants.
• Protein domain structure and GC content play distinct roles in modulating translational accuracy across different plant lineages (dicots and monocots).
• Evolutionary pressures on translational accuracy are complex and clade-specific.