Plant organellar genomes: much done, much more to do

• Published in: Trends in plant science 2024-07, Vol.29 (7), p.754-769
• Main Authors: Wang, Jie, Kan, Shenglong, Liao, Xuezhu, Zhou, Jiawei, Tembrock, Luke R., Daniell, Henry, Jin, Shuangxia, Wu, Zhiqiang
• Format: Article
• Language: English
• Subjects: genome editing; mitochondria; organellar genome; plastid transformation; structural variation
• ISSN: 1360-1385; 1878-4372; 1878-4372
• DOI: 10.1016/j.tplants.2023.12.014

Advances in technology have led to a large increase in the number of plant organellar sequences, but sampling remains uneven.Most land-plant mitogenomes are difficult to assemble accurately due to alternative structural configurations and interference from transferred sequences.Pan-organellar genomes have provided new evolutionary insights and have provided targets for editing to study changes in gene function during lineage divergence.Organellar genome editing – such as mitochondrially targeted transcription activator-like effector nucleases (TALENs) and double-stranded DNA-specific cytidine deaminase (DddA)-derived cytosine base editors – enables the functional verification of open reading frames (ORFs) and non-coding regions.Plastid transformation has been used in an array of modifications – such as to improve photosynthetic efficiency, and the biosynthesis of vaccines – while mitochondrial transformation lags far behind due to technical challenges. Plastids and mitochondria are the only organelles that possess genomes of endosymbiotic origin. In recent decades, advances in sequencing technologies have contributed to a meteoric rise in the number of published organellar genomes, and have revealed greatly divergent evolutionary trajectories. In this review, we quantify the abundance and distribution of sequenced plant organellar genomes across the plant tree of life. We compare numerous genomic features between the two organellar genomes, with an emphasis on evolutionary trajectories, transfers, the current state of organellar genome editing by transcriptional activator-like effector nucleases (TALENs), transcription activator-like effector (TALE)-mediated deaminase, and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas), as well as genetic transformation. Finally, we propose future research to understand these different evolutionary trajectories, and genome-editing strategies to promote functional studies and eventually improve organellar genomes. Plastids and mitochondria are the only organelles that possess genomes of endosymbiotic origin. In recent decades, advances in sequencing technologies have contributed to a meteoric rise in the number of published organellar genomes, and have revealed greatly divergent evolutionary trajectories. In this review, we quantify the abundance and distribution of sequenced plant organellar genomes across the plant tree of life. We compare numerous genomic features betwe