Voltage-Dependent Anion-Selective Channels and Other Mitochondrial Membrane Proteins Form Diverse Complexes in Beetroots Subjected to Flood-Induced Programmed Cell Death

Abstract

In plants, programmed cell death (PCD) is involved in both the development and the response to biotic and abiotic aggressions. In early stages of PCD, mitochondrial membranes are made permeable by the formation of permeability transition pores, whose protein composition is debated. Cytochrome c (cyt c) is then released from mitochondria, inducing the degradation of chromatin characteristic of PCD. Since flooding stress can produce PCD in several plant species, the first goal of this study was to know if flooding stress could be used to induce PCD in Beta vulgaris roots. To do this, 2-month-old beet plants were flood-stressed from 1 to 5 days, and the alterations indicating PCD in stressed beetroot cells were observed with a confocal fluorescence microscope. As expected, nuclei were deformed, and chromatin was condensed and fragmented in flooded beetroots. In addition, cyt c was released from mitochondria. After assessing that flood stress induced PCD in beetroots, the composition of mitochondrial protein complexes was observed in control and flood-stressed beetroots. Protein complexes from isolated mitochondria were separated by native gel electrophoresis, and their proteins were identified by mass spectrometry. The spectra count of three isoforms of voltage-dependent anion-selective channels (VDACs) increased after 1 day of flooding. In addition, the size of the complexes formed by VDAC was higher in flood-stressed beetroots for 1 day (∼200 kDa) compared with non-stressed ones (∼100 kDa). Other proteins, such as chaperonin CPN60-2, also formed complexes with different masses in control and flood-stressed beetroots. Finally, possible interactions of VDAC with other proteins were found performing a cluster analysis. These results indicate that mitochondrial protein complexes formed by VDAC could be involved in the process of PCD in flood-stressed beetroots. Data are available via ProteomeXchange with identifier PXD027781.

Proteomic Studies of Roots in Hypoxia-Sensitive and -Tolerant Tomato Accessions Reveal Candidate Proteins Associated with Stress Priming

“…VDAC are most abundant in the outer mitochondrial membrane and are also involved in programmed cell death as a response to biotic and abiotic stresses. An increase in VDAC was noted for flood stressed Beta vulgaris roots [62].…”

A review on the analysis of nutritional composition of beetroot powder

“…Beetroot grows well in deep and well-drained, loose, loamy, sandy soils with a temperature ranging from 4.5 to 30 °C for seed germination. Beetroot needs a pH of 5.8 to 7.0 and it can tolerate a pH of up to 7.6 [33] . The advantage of fertilizers based on soil testing is an vital tool to prescribe nutrient doses for beetroot.…”

“…The advantage of fertilizers based on soil testing is an vital tool to prescribe nutrient doses for beetroot. The quantity of fertilizers that could be contributed to beetroot is 40 kg nitrogen (N), 21 kg phosphorus pentoxide, and 30 kg potassium oxide [33] . Beetroot can be harvested from early summer through to mid-autumn, which is normally ready for harvest between 75 and 90 days in summer and 100 and 120 days in winter [34] .…”

Mitochondrial Peroxiredoxin-IIF (PRXIIF) Activity and Function during Seed Aging

“…During seed aging, ROS and redox changes alter gene expression that in cases of severe redox disequilibria initiate programmed cell death (PCD). As in other plant cells and tissues, redox-dependent activation of the voltage-dependent anion-selective channel (VDAC) may allow for release of cytochrome c from the mitochondrial intermembrane space and induce PCD [ 11 ]. Accompanied DNA fragmentation leads to the ladder structure of DNA, and contraction of the cytoplasm.…”