Scientists reveal the evolutionary fate of missing genes in mitochondria of gymnosperms

Scientists reveal the evolutionary fate of missing genes in mitochondria of gymnosperms

Scientists reveal the evolutionary fate of missing genes in gymnosperms mitochondria

Recently, the team of Wang Xiaoquan, a researcher at the Institute of Botany, Chinese Academy of Sciences, performed high-throughput DNA and cDNA sequencing on representative species of all 13 families of gymnosperms, and spliced ​​their mitochondrial genomes, revealing changes in the mitochondrial gene content of gymnosperms.
The evolutionary fate of missing genes, combined with published land plant mitochondrial genome data, discussed the factors affecting the differences in land plant mitochondrial gene composition
.

Related research results were published in the international academic journal "Biomedical Center Biology"

Mitochondria lost a large number of genes after the initiation of endosymbiosis events and evolved into semi-autonomous organelles
.

The mitochondrial genomes of different biological lines are very different, especially compared to animals and other eukaryotes (the protein-coding gene content is relatively stable), the transfer/loss of mitochondrial genes in multiple branches of land plants often occurs

Gymnosperms represent the four major branches of the original five major branches of seed plants, and are sister groups of angiosperms, including about 1,000 species in 13 families
.

Previous studies have found that the mitochondrial gene composition of gymnosperms is very different between different branch lines, which provides a good system for exploring the evolutionary fate of mitochondrial missing genes

Researchers compared the sequencing depth of the gene and its relative copy number in the genome, structure, RNA editing site, evolution rate, GC content, and protein hydrophobicity.
The mitochondrial genome encodes all 41 protein-coding genes, while the number of mitochondrial genes in Conifer II (other conifers except Pinaceae) and Niteng plants has been greatly reduced
.

In Conifer II, mitochondrial gene transfer is very frequent, but direct loss rarely occurs; in Niteng plants, mitochondrial gene transfer and loss are very frequent

In addition, the researchers also found that compared with mitochondrial gene transfer/loss events in angiosperms (usually occurring in a certain genus or even a certain species), in gymnosperms (except Ephedra), most mitochondrial gene transfer /The loss event happened very early
.

Based on the distribution of the RNA editing site of the transferred gene and the difference in the number and phase of introns, the researchers speculated that the mitochondrial genes of Conifer II and Niteng plants may be transferred through a two-step transfer mechanism, that is, reverse transcription and subsequent DNA.

Based on the mitochondrial gene data of gymnosperms obtained in this study, the researchers combined with published land plant mitochondrial genomes to conduct a comprehensive analysis and found that gene length, GC content, hydrophobicity, and nucleotide substitution rate may be the same as those of land plant mitochondrial genomes.
The composition difference is related
.

Kan Shenglong, a doctoral student from the Institute of Botany, Chinese Academy of Sciences, is the first author of the paper.
Researchers Wang Xiaoquan and Ran Jinhua are co-corresponding authors
.

The research was supported by the Frontier Science Key Research Program of the Chinese Academy of Sciences , the National Key Research and Development Program, the National Natural Science Foundation of China, and the Youth Innovation Promotion Association of the Chinese Academy of Sciences

Chinese Academy of Sciences

Related paper information: https://doi.

https://doi.
org/10.
1186/s12915-021-01096-z