Chloroplast competition is controlled by lipid biosynthesis in evening primroses

Area of Science:

• Plant Biology
• Genetics
• Evolutionary Biology

Background:

• Organellar genomes are typically maternally inherited in eukaryotes, but the underlying molecular mechanisms and evolutionary drivers remain poorly understood.
• Biparental inheritance can facilitate the spread of selfish cytoplasmic elements, such as aggressive plastids incompatible with the nuclear genome.

Purpose of the Study:

• To investigate the molecular basis of plastid competitiveness and its role in determining chloroplast inheritance patterns.
• To identify specific genes and genetic variations responsible for differential plastid competitiveness.

Main Methods:

• Analysis of rapidly evolving genes within the plastid genome of Oenothera.
• Investigating the role of repeats in regulatory regions of accD and ycf2 genes.
• Correlating genetic polymorphisms with metabolic phenotypes, lipid synthesis, and plastid envelope membrane composition.

Main Results:

• The competitive ability of plastids is a metabolic trait influenced by rapidly evolving genes in the plastid genome.
• Specific repeats in the regulatory regions of accD and ycf2 genes are linked to variations in plastid competitive behavior.
• Polymorphisms in these genes affect lipid synthesis and plastid envelope membrane profiles, influencing plastid division and turnover rates.

Conclusions:

• Identified cytoplasmic drive loci that control the outcome of biparental chloroplast transmission.
• Plastid competitiveness, driven by specific genes, dictates whether inheritance is uniparental or biparental.
• This study provides insights into the evolutionary forces shaping organellar inheritance.