Mitochondrial genome of non-photosynthetic mycoheterotrophic plant Hypopitys monotropa,its structure, gene expression and RNA editing

Abstract

20 The plants that lost the ability to photosynthesis (heterotrophic) are characterized by a number of 21 changes at all levels of organization -morphological, physiological and genomic. Heterotrophic 22 plants divide into two large categories -parasitic and mycoheterotrophic. The question of to 23 what extent these changes are similar in these two categories is still open. Plastid genomes of 24 non-photosynthetic plants are well characterized and they demonstrate similar patterns of 25 reduction in both groups. In contrast, little is known about mitochondrial genomes of 26 mycoheterotrophic plants. We report the structure of the mitochondrial genome of Hypopitys 27 monotropa, a mycoheterotrophic member of Ericaceae, and the expression of mitochondrial 28 genes. In contrast to its highly reduced plastid genome, the mitochondrial genome of H. 29 monotropa is larger than that of its photosynthetic relative Vaccinium macrocarpon, its complete 30 size is ~810 Kbp. We found an unusually long repeat-rich structure of the genome that suggests 31 the existence of linear fragments. Despite this unique feature, the gene content of the H. 32 monotropa mitogenome is typical of flowering plants. No acceleration of substitution rates is 33 observed in mitochondrial genes, in contrast to previous observations on parasitic non-34 photosynthetic plants. Transcriptome sequencing revealed trans-splicing of several genes and 35 RNA editing in 33 genes of 38. Notably, we did not find any traces of horizontal gene transfer 36 from fungi, in contrast to plant parasites which extensively integrate genetic material from their 37 hosts. 38 Introduction 39 A

Mitochondrial Genome of Fagopyrum esculentum and the Genetic Diversity of Extranuclear Genomes in Buckwheat

“…This is true especially for the cases where the data are not limited by the shotgun short-read libraries but include mate pair libraries and/or long read data that allow resolving of long repeats. There are several reports of bipartite mitogenomes [15,16] including in Polygonaceae [7]. The higher number of circles is much rarer, in particular a number of circles more than 10 was found only in 4 out of 307 assembled plant mitochondrial genomes deposited in NCBI GenBank (as of 21 February of 2020).…”