Molecular Structures In Plant Respiration Revealed By Scientists
All plants and animals release energy from food through respiration. This process occurs in mitochondria at the cellular level. But how plants extract energy from sources is different from that of animals. We can bring a revolutionary change in agriculture if we discover those differences.
For growth and biomass accumulation, plant respiration is a crucial process, said Maria Maldonado, a postdoctoral researcher in the lab of James Letts, College of Biological Sciences. Biomass and the interplay between photosynthesis and respiration are correlated to the extent of growth in crops.
Letts and colleagues provide the first-ever, 3-D structure of the largest protein complex (complex I) involved in the plant mitochondrial electron transport chain at an atomic level in a study published in eLife.
The higher resolution structures of the complete electron transport chain and even supercomplexes were available for mammals or years, but for plants, nothing was available till now.
Researchers could improve agriculture, and even better pesticides could be designed if the structure and functionality of these plant protein complexes were known. There are many pesticides that target the electron transport chain complexes of the pest’s mitochondria. By understanding the structures of
the plant’s complexes, better fungicide or pesticides could be designed that would kill the pest or fungus but not the plants or humans that eat them.Plants conduct photosynthesis using chloroplast to make their food. But for scientists studying the molecular minutiae of the mitochondrial electron transport chain, the chloroplast could pose a problem. The chloroplasts and mitochondria in plants have a similar size and physical properties. Due to these similarities, it is hard to separate mitochondria from chloroplasts in a laboratory.
To resolve this, scientists grew mung beans (Vigna radiate) in the dark, preventing chloroplasts from developing. Mung beans store energy in the form of seed oils, and the oil is burnt like fuel during sprouting. The photosynthesis is limited in them without chloroplasts, which limits their energy streams.
The scientists obtained a clearer structural image of complex I and its subcomplexes by separating mitochondria from chloroplasts. To solve the structure of the complexes after purifying them from mitochondrial samples, they used single-particle cryoelectron microscopy.
Scientists were able to see at an atomic level how the building block proteins of complex I are assembled with the help of these structures, and they understood how the assembly differed from that of bacteria, yeast, and mammals.
The researchers think that the unique modular structure of complex I offer plants the flexibility to thrive as immobile organisms.
Researchers can now plan to conduct functional experiments with the molecular structure of complex I involved in plant respiration in hand. And it is possible to open a new doorway to making crop plants more energy efficient by further understanding complex I’s functionality.
