Extrachromosomal circular DNA: A neglected nucleic acid molecule in plants

Throughout the years, most plant genomic studies were focused on nuclear chromosomes. Extrachromosomal circular DNA (eccDNA) has largely been neglected for decades since its discovery in 1965. While initial research showed that eccDNAs can originate from highly repetitive sequences, recent findings show that many regions of the genome can contribute to the eccDNA pool. Currently, the biological func-tions of eccDNAs, if any, are a mystery but recent studies have indicated that they can be regulated by different genomic loci and contribute to stress response and adaptation. In this review, we outline current relevant technological developments facilitating eccDNA identification and the latest discoveries about eccDNAs in plants. Finally, we explore the probable functions and future research directions that could be under-taken with respect to different eccDNA sources.

Automated summary

Most plant genomic studies have focused on nuclear chromosomes, neglecting research on extrachromosomal circular DNA (eccDNA). Recent findings show that eccDNAs can originate from various regions of the genome and play a role in stress response and adaptation in plants. This review outlines current technological developments for identifying eccDNA and discusses the functions and future research directions regarding different sources of eccDNA.