Transcript No Slide Title

Some mt & cp proteins contain subunits encoded by organelle’s
genome
Plant mtDNA encodes ~13 proteins, also rRNA & tRNA
• subunits of ATP synthase & complexes I, II, III & IV
• some mRNA are trans-spliced from 2 diff transcripts!
• some mRNA are edited: bases changed after synthesis!
Plant mtDNA
mtDNA recombines to form new genes, some poison pollen
development to create cytoplasmic male sterility
Pollen don't transmit mito!
CMS
A long noncoding RNA regulates photoperiod-sensitive male sterility,
an essential component of hybrid rice(2012) doi:
10.1073/pnas.1121374109
A non-coding RNA locus mediates environment-conditioned male
sterility in rice. (2012) Cell Research 22:791–792.
doi:10.1038/cr.2012.43
Comparative expression profiling of miRNA during anther
development in genetic male sterile and wild type cotton. (2013) BMC
Plant Biology 13:66
Differential Proteomic Analysis of Anthers between Cytoplasmic
Male Sterile and Maintainer Lines in Capsicum annuum L.(2013) Int.
J. Mol. Sci. 14(11), 22982-22996; doi:10.3390/ijms141122982
Transcriptome map of plant mitochondria reveals islands of
unexpected transcribed regions (2011) BMC Genomics 12: 279.
Heterozygous alleles restore male fertility to cytoplasmic male-sterile
radish (Raphanus sativus L.): a case of overdominance(2013) J. Exp.
Bot. 64: 2041-2048.
CMS
have major increase in respiration and # mitochondria after meiosis
40 x increase in mt/ cell in tapetum
20x in sporogenous cells
Often arise due to recombination
creating weird fusion encoding
defective protein: poisons respiration
Not enough energy to make good pollen
CMS
RF genes often encode protein which restores good mRNA eg. by
splicing fusion in Hong-Lian cms rice
Or by blocking WA352 expression in Wild Abortive CMS rice
Constant battle: mito evolve way to kill pollen and nucleus evolves
way to overcome it.
Mitochondria and the immune system
Mitochondria are involved in many
aspects of innate immunity
•Pathogens and damaged mito
trigger very similar responses
•pathogen-associated molecular
patterns (PAMPs) are bound by
pattern-recognition receptors (PRRs)
that trigger inflammatory responses
•damage-associated molecular
patterns (DAMPs) released by broken
mito bind the same receptors & trigger
same responses.
Mitochondria and the immune system
Mitochondria are involved in many aspects of innate immunity
•Mito play important role in recognizing & fighting viruses
•Via RLR (retinoic acid-inducible receptors) pathway that detects
dsRNA
Mitochondria and the immune system
•Mito play important role in recognizing & fighting viruses
•Via RLR (retinoic acid-inducible receptors) pathway that detects
dsRNA
•MAVS (mitochondrial antiviral
signaling) protein on MOM is key
Mitochondria and the immune system
• Mito play important role in recognizing & fighting viruses
• Via RLR (retinoic acid-inducible receptors) pathway that detects
dsRNA
• MAVS (mitochondrial antiviral
signaling) protein on MOM is key
• dsRNA receptors bind MAVS &
trigger interferon & cytokine
synthesis
Mitochondria and the immune system
•MAVS (mitochondrial antiviral signaling) protein on MOM is key
•dsRNA receptors bind MAVS & trigger interferon & cytokine
Synthesis
•Viruses also interact with mt in countless specific ways
Mitochondria and the immune system
•Viruses also interact with mt in countless specific ways
•Many involve blocking Programmed Cell Death pathways
Mitochondria and cell death
Cells die many ways, but
mito are often involved
Programmed cell death vs necrosis
Necrosis:
progressive loss of membrane integrity
swelling of cytoplasm, release of cell constituents
Often follows irreversible injury
Passive
Indiscriminate
PCD
Active
Orderly process mediated by
intracellular death programs
May or may not be due to an
external factor
Nuclear condensation
Condensation of PM
Types of programmed cell death
Apoptosis
Autophagy
Pyroptosis
Ferroptosis
Plant programmed cell death
Necroptosis
Apoptosis
Occurs as normal part of development
e.g. patterning of hands/feet
Apoptosis
Occurs as normal part of development
Ordered process that breaks cell into easily recycled
pieces
Apoptosis
Occurs as normal part of development
Is also triggered by many kinds of damage
Especially to DNA
Many cancer cells do not commit apoptosis
Apoptosis
Occurs as normal part of development
Ordered process that breaks cell into easily recycled pieces
Caspases digest proteins
Apoptosis
Ordered process that breaks cell into easily recycled pieces
Caspases digest proteins
CAD digests DNA
Apoptosis
Occurs as normal part of development
Two basic steps: commitment and execution
Apoptosis
Occurs as normal part of development
Two basic steps: commitment and execution
Commitment depends on interplay between various signals
Bax & Bcl2 have opposite effects
Apoptosis
Two basic steps: commitment and execution
Commitment depends on interplay between various signals
Bax & Bcl2 have opposite effects
2 main pathways: extrinsic & intrinsic