Plant mitochondria – past, present and future

Abstract

The study of plant mitochondria started in earnest around 1950 with the first isolations of mitochondria from animal and plant tissues. The first 35 years were spent establishing the basic properties of plant mitochondria and plant respiration using biochemical and physiological approaches. A number of unique properties (compared to mammalian mitochondria) were observed: (i) the ability to oxidize malate, glycine and cytosolic NAD (P)H at high rates; (ii) the partial insensitivity to rotenone, which turned out to be due to the presence of a second NADH dehydrogenase on the inner surface of the inner mitochondrial membrane in addition to the classical Complex I NADH dehydrogenase; and (iii) the partial insensitivity to cyanide, which turned out to be due to an alternative oxidase, which is also located on the inner surface of the inner mitochondrial membrane, in addition to the classical Complex IV, cytochrome oxidase. With the appearance of molecular biology methods around 1985, followed by genomics, further unique properties were discovered: (iv) plant mitochondrial DNA (mtDNA) is 10-600 times larger than the mammalian mtDNA, yet it only contains approximately 50% more genes; (v) plant mtDNA has kept the standard genetic code, and it has a low divergence rate with respect to point mutations, but a high recombinatorial activity; (vi) mitochondrial mRNA maturation includes a uniquely complex set of activities for processing, splicing and editing (at hundreds of sites); (vii) recombination in mtDNA creates novel reading frames that can produce male sterility; and (viii) plant mitochondria have a large proteome with 2000-3000 different proteins containing many unique proteins such as 200-300 pentatricopeptide repeat proteins. We describe the present and fairly detailed picture of the structure and function of plant mitochondria and how the unique properties make their metabolism more flexible allowing them to be involved in many diverse processes in the plant cell, such as photosynthesis, photorespiration, CAM and C4 metabolism, heat production, temperature control, stress resistance mechanisms, programmed cell death and genomic evolution. However, it is still a challenge to understand how the regulation of metabolism and mtDNA expression works at the cellular level and how retrograde signaling from the mitochondria coordinates all those processes.

Mitochondrial genome of Garcinia mangostana L. variety Mesta

“…The large repeats (> 1 kb) might cause homologous recombination and eventually lead to the different configuration of the mitogenomes 43 . Apart from large repeats, both direct and inverse repeats also contribute to the subgenomic molecules 6 . Repeats detected in Mesta mitogenome using web-based REPuter was low (5.8%) compared to C. melo (42.7%) 44 , V. vinifera (6.8%) 45 , and N. colorata (48.89%) 15 but higher than P. dactylifera (2.3%) 27 .…”

Impacts of Mn, Fe, and Oxidative Stressors on MnSOD Activation by AtMTM1 and AtMTM2 in Arabidopsis

“…The plant mitochondrial carrier family (MCF) contains approximately 60 proteins that coordinate metabolic and ionic homeostasis between the cytosol and mitochondria [ 36 , 37 , 38 , 39 ]. The mitochondrial MCF proteins, AtMTM1 and AtMTM2, are Mn-specific carrier proteins involved in MnSOD activation in Arabidopsis [ 30 , 31 ].…”

Mitochondrial Genome of Garcinia mangostana L. variety Mesta

“…The large repeats (>1 kb) might cause homologous recombination and eventually lead to the different configuration of the mitogenomes 37 . Apart from large repeats, both direct and inverse repeats also contribute to the subgenomic molecules 7 . Repeats detected in Mesta mitogenome using web-based REPuter was low (5.8%) compared to C. melo (42.7%) 38 , V. vinifera (6.8%) 39 , and N. colorata (48.89%) 40 but higher than P. dactylifera (2.3%) 21 .…”