Abstract
BackgroundIn most angiosperms, the inheritance of the mitochondria takes place in a typical maternal manner. However, very less information is available about if the existence of structural variations or not in mitochondrial genomes (mitogenomes) between maternal parents and their progenies.ResultsIn order to find the answer, a stable rice backcross inbred line (BIL) population was derived from the crosses of Oryza glaberrima/Oryza sativa//Oryza sativa. The current study presents a comparative analysis of the mitogenomes between maternal parents and five BILs. There were recorded universal structural variations such as reversal, translocation, fusion, and fission among the BILs. The repeat-mediated recombination and non-homologous end-joining contributed virtually equal to the rearrangement of mitogenomes. Similarly, the relative order, copy-number, expression level, and RNA-editing rate of mitochondrial genes were also extensively varied among BILs.ConclusionsThese novel findings unraveled an unusual mystery of the maternal inheritance and possible cause for heterogeneity of mitogenomes in rice population. The current piece of work will greatly develop our understanding of the plant nucleo-cytoplasmic interaction and their potential role in plant growth and developmental processes.
Highlights
In most angiosperms, the inheritance of the mitochondria takes place in a typical maternal manner
In order to prove this hypothesis, we developed a stable rice BC2F12 backcross inbred line (BIL) population which inherited their mitochondrial genomes from the same maternal parent (O. glaberrima × O. sativa 93– 11)
Backcross inbred lines derived from crosses of O. glaberrima and O. sativa showed different mitotypes from the maternal line In the quest for the existence of dynamic inheritance of rice mitogenome, two sets of BC2F12 backcross inbred lines (BIL) were constructed by crossing O. sativa 93–11 with O. glaberrima line 675 as maternal line, and introgressed using 93–11 and O. glaberrima as the paternal line, respectively, in an attempt to simulate the natural evolutionary process of rice (Fig. 1a)
Summary
The inheritance of the mitochondria takes place in a typical maternal manner. Recent genomic research suggests that both indica, as well as japonica rice, were originated from O. rufipogon simultaneously [16, 17] It indicates that the mitogenomes of indica and japonica varieties are well-differentiated and show a narrow diversity in each subspecies if their mitogenomes strictly persist in stable maternal inheritance. The mitogenomes of 224 worldwide landraces of rice were analyzed using 32 mitotypespecific molecular markers [19], all the landraces were classified into 20 subgroups, and the indica and japonica lines were found evenly distributed in each clade (Supplementary Fig. S1), implying a strong differentiation of rice mitogenomes [15, 17] Such characteristics make rice as an apt model plant for the investigation of mitogenome inheritance and evolution patterns
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