Complete Plastid and Mitochondrial Genomes of <i>Aeginetia indica</i> Reveal Intracellular Gene Transfer (IGT), Horizontal Gene Transfer (HGT), and Cytoplasmic Male Sterility (CMS)

• Main Authors: Kyoung-Su Choi, Seonjoo Park
• Format: Article
• Language: English
• Published: MDPI AG 2021-06-01
• Series: International Journal of Molecular Sciences
• Subjects: <i>Aeginetia indica</i>; Orobanchaceae; plastid; mitogenome; intracellular gene transfer (IGT); horizontal gene transfer (HGT)
• Online Access: https://www.mdpi.com/1422-0067/22/11/6143
• ISSN: 1661-6596; 1422-0067

Orobanchaceae have become a model group for studies on the evolution of parasitic flowering plants, and <i>Aeginetia indica</i>, a holoparasitic plant, is a member of this family. In this study, we assembled the complete chloroplast and mitochondrial genomes of <i>A. indica</i>. The chloroplast and mitochondrial genomes were 56,381 bp and 401,628 bp long, respectively. The chloroplast genome of <i>A. indica</i> shows massive plastid genes and the loss of one IR (inverted repeat). A comparison of the <i>A. indica</i> chloroplast genome sequence with that of a previous study demonstrated that the two chloroplast genomes encode a similar number of proteins (except <i>atpH</i>) but differ greatly in length. The <i>A. indica</i> mitochondrial genome has 53 genes, including 35 protein-coding genes (34 native mitochondrial genes and one chloroplast gene), 15 tRNA (11 native mitochondrial genes and four chloroplast genes) genes, and three rRNA genes. Evidence for intracellular gene transfer (IGT) and horizontal gene transfer (HGT) was obtained for plastid and mitochondrial genomes. ψ<i>ndhB</i> and ψ<i>cemA</i> in the <i>A. indica</i> mitogenome were transferred from the plastid genome of <i>A. indica</i>. The <i>atpH</i> gene in the plastid of <i>A. indica</i> was transferred from another plastid angiosperm plastid and the <i>atpI</i> gene in mitogenome <i>A. indica</i> was transferred from a host plant like <i>Miscanthus siensis</i>. <i>Cox2</i> (<i>orf43</i>) encodes proteins containing a membrane domain, making ORF (Open Reading Frame) the most likely candidate gene for CMS development in <i>A. indica</i>.