MULTICHROMOSOMAL STRUCTURE AND FOREIGN MITOCHONDRIAL GENES IN Ombrophytum subterraneum

PONCE G.; ROULET ME.; GARCIA LE.; GANDINI LC.

Mendoza

Congreso; XVII Congreso Latinoamericano de Genética (ALAG); 2019

Vascular connections between parasitic plants and their hosts allow the passage of water, nutrients, and nucleic acids. Consequently, parasitic relationships facilitate the exchange of genetic information, a process known as horizontal gene transfer (HGT). Most cases of plant-to-plant HGT involve the mitochondrial and nuclear genomes. In this study, we sequenced and analyzed the mitochondrial genome (mtDNA) of the angiosperm holoparasite Ombrophytum subterraneum (Balanophoraceae). Total DNA extraction and massive sequencing with Illumina technology were performed. The mtDNA assembly was carried out based on information of the Illumina paired-end reads. The genome is composed of 54 independent circular chromosomes (4-27kb) totaling 713,777 bp. This multipartite chromosomal architecture was recently described in a close relative, Lophophytum mirabile. Maximum Likelihood phylogenetic analyses were performed to assess the evolutionary history of each gene and BLAST searches to unveil the origin of intergenic regions. About 25% of the genes were associated with species of the Family Asteraceae, indicating that they were transferred from asterid hosts. Most foreign genes co-exist with native homologs in the mitochondrial genome of O. subterraneum. Additional studies are required to understand which copy is functional. The presence of introns and foreign intergenic regions flanking foreign genes support the mitochondrial fusion compatibility model via mitochondrion-to-mitochondrion horizontal transfer.