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Plant biofuel related Novel biofuel Novel ways to enhance biofuel production Biophotovoltaics Photosynthesis related Enhancing light harvesting Enhancing carbon capture Carboxysomes in higher plants Carbonic anhydrase C4 rice Plant biotechnology related Plantibodies Other useful products made in plants Bioremediation Heavy metals Pesticides
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Agriculture related Improving nutritional value by GMO or wide-breeding Vitamins Essential amino acids Iron Other nutrients Reducing fertilizer needs Selecting for water-use efficiency Selecting for efficiency of other nutrients Moving N-fixation to other species Improving mycorrhizae GMO for weed and pest control Round-up resistance BT toxin Treating viruses, viroids, etc by GMO
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Light regulation of Plant Development
Plants use light as food and information Use information to control development
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Light regulation of growth
Plants sense Light quantity Light quality (colors) Light duration Direction it comes from Have photoreceptors that sense specific wavelengths
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Light regulation of growth
Red light (666 nm) promotes germination Far red light (>700 nm) blocks germination After alternate R/FR color of final flash decides outcome Seeds don't want to germinate in the shade! Pigment is photoreversible
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Phytochrome Made as inactive cytoplasmic Pr that absorbs at 666 nm or in blue Converts to active Pfr that absorbs far red (730nm)
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Types of Phytochrome Responses
Two categories based on speed Rapid biochemical events Morphological changes
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Types of Phytochrome Responses
3 classes based on fluence (amount of light needed) VLF:induced by 0.1 nmol/m-2 , 50nmol/m-2 2. LF: induced by 1 µmol/m-2, µmol/m-2 3. HIR: require prolonged exposure to higher fluence Effect is proportional to Fluence
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Types of Phytochrome Responses
3 classes based on fluence (amount of light needed) VLF:induced by 0.1 nmol/m-2 , 50nmol/m-2 2. LF: induced by 1 µmol/m-2, µmol/m-2 3. HIR: require prolonged exposure to higher fluence Different responses = Different phytochromes: 3 in rice, 5 in Arabidopsis
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Types of Phytochrome Responses
Different responses = Different phytochromes: 3 in rice, 5 in Arabidopsis PHYA mediates VLF and HIR due to FR Very labile in light 2. PHYB mediates LF and HIR due to R Stable in light
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Types of Phytochrome Responses
PHYA & PHYB are often antagonistic. In sunlight PHYB mainly controls development In shade PHYA 1st controls development, since FR is high But PHYA is light-labile; PHYB takes over & stem grows "shade-avoidance"
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Phytochrome Pr has cis-chromophore
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Phytochrome Pr has cis-chromophore Red converts it to trans = active shape
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Phytochrome Pr has cis-chromophore Red converts it to trans = active shape Far-red reverts it to cis
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Phytochrome Pfr is a protein kinase: acts by kinasing key proteins some stays in cytoplasm & activates ion pumps
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Phytochrome Pfr is a protein kinase: acts by kinasing key proteins some stays in cytoplasm & activates ion pumps Rapid responses are due to changes in ion fluxes
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Phytochrome Pfr is a protein kinase: acts by kinasing key proteins some stays in cytoplasm & activates ion pumps Rapid responses are due to changes in ion fluxes Increase growth by activating PM H+ pump
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Phytochrome Pfr is a protein kinase: acts by kinasing key proteins some stay in cytoplasm & activate ion pumps Rapid responses are due to changes in ion fluxes most enter nucleus and kinase transcription factors
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Phytochrome some stay in cytoplasm & activate ion pumps Rapid responses are due to changes in ion fluxes most enter nucleus and kinase transcription factors Slow responses are due to changes in gene expression
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Phytochrome most enter nucleus and kinase transcription factors Slow responses are due to changes in gene expression Many targets of PHY are transcription factors, eg PIF3
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Phytochrome most enter nucleus and kinase transcription factors Slow responses are due to changes in gene expression Many targets of PHY are transcription factors, eg PIF3 Activate cascades of genes for photomorphogenesis
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Phytochrome Slow responses are due to changes in gene expression Many targets of PHY are transcription factors, eg PIF3 Activate cascades of genes for light responses Some overlap, and some are unique to each phy
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Phytochrome Slow responses are due to changes in gene expression Many targets of PHY are transcription factors, eg PIF3 Activate cascades of genes for light responses Some overlap, and some are unique to each phy 20% of genes are light-regulated
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Phytochrome 20% of genes are light-regulated Protein degradation is important for light regulation
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Phytochrome 20% of genes are light-regulated Protein degradation is important for light regulation Cop mutants can’t degrade specific proteins
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Phytochrome Protein degradation is important for light regulation Cop mutants can’t degrade specific proteins COP1/SPA targets specific transcription factors for degradation
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Phytochrome Protein degradation is important for light regulation Cop mutants can’t degrade specific proteins COP1/SPA targets specific TF for degradation DDA1/DET1/COP10 target other proteins for degradation
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Phytochrome Protein degradation is important for light regulation Cop mutants can’t degrade specific proteins COP1/SPA targets specific TF for degradation DDA1/DET1/COP10 target other proteins for degradation Other COPs form part of COP9 signalosome
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Phytochrome Protein degradation is important for light regulation Cop mutants can’t degrade specific proteins COP1/SPA targets specific TF for degradation DDA1/DET1/COP10 target other proteins Other COPs form part of COP9 signalosome W/O COPs these TF act in dark
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Phytochrome COPs target specific TF for degradation W/O COPs they act in dark In light COP1 is exported to cytoplasm so TF can act Tags PHYA by itself on the way out!
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Other Phytochrome Responses
In shade avoidance FR stimulates IAA synthesis from trp! Occurs in < 1 hour
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Other Phytochrome Responses
In shade avoidance FR stimulates IAA synthesis from trp! Occurs in < 1 hour Also occurs in response to endogenous ethylene!
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Other Phytochrome Responses
Flowering under short days is controlled via protein deg COP & CUL4 mutants flower early
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Other Phytochrome Responses
Flowering under short days is controlled via protein deg COP & CUL4 mutants flower early Accumulate FT (Flowering locus T) mRNA early FT mRNA abundance shows strong circadian rhythm
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Other Phytochrome Responses
Circadian rhythms Many plant responses, some developmental, some physiological, show circadian rhythms
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Circadian rhythms Many plant responses, some developmental, some physiological, show circadian rhythms Leaves move due to circadian ion fluxes in/out of dorsal & ventral motor cells
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Circadian rhythms Many plant responses show circadian rhythms Once entrained, continue in constant dark
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Circadian rhythms Many plant responses show circadian rhythms Once entrained, continue in constant dark, or light
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Circadian rhythms Many plant responses show circadian rhythms Once entrained, continue in constant dark, or light! Gives plant headstart on photosynthesis, other processes that need gene expression
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Circadian rhythms Many plant responses show circadian rhythms Once entrained, continue in constant dark, or light! Gives plant headstart on photosynthesis, other processes that need gene expression eg elongation at night!
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Circadian rhythms Gives plant headstart on photosynthesis, other processes that need gene expression eg elongate at night! Endogenous oscillator is temperature-compensated, so runs at same speed at all times
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Circadian rhythms Endogenous oscillator is temperature-compensated, so runs at same speed at all times Is a negative feedback loop of transcription-translation Light & TOC1 activate LHY & CCA1 at dawn
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Circadian rhythms Light & TOC1 activate LHY & CCA1 at dawn LHY & CCA1 repress TOC1 in day, so they decline too
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Circadian rhythms Light & TOC1 activate LHY & CCA1 at dawn LHY & CCA1 repress TOC1 in day, so they decline too At night TOC1 is activated (not enough LHY & CCA1)
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Circadian rhythms Light & TOC1 activate LHY & CCA1 at dawn LHY & CCA1 repress TOC1 in day, so they decline too At night TOC1 is activated (not enough LHY & CCA1) Phytochrome entrains the clock
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Circadian rhythms Light & TOC1 activate LHY & CCA1 at dawn LHY & CCA1 repress TOC1 in day, so they decline too At night TOC1 is activated (not enough LHY & CCA1) Phytochrome entrains the clock So does blue light
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Blue Light Responses Circadian Rhythms
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Blue Light Responses Circadian Rhythms Solar tracking
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Blue Light Responses Circadian Rhythms Solar tracking Phototropism
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Blue Light Responses Circadian Rhythms Solar tracking Phototropism Inhibiting stem elongation
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Blue Light Responses Circadian Rhythms Solar tracking Phototropism Inhibiting stem elongation Chloroplast movement
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Blue Light Responses Circadian Rhythms Solar tracking Phototropism Inhibiting stem elongation Chloroplast movement Stomatal opening
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Blue Light Responses Circadian Rhythms Solar tracking Phototropism Inhibiting stem elongation Chloroplast movement Stomatal opening Gene expression
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Blue Light Responses Circadian Rhythms Solar tracking Phototropism Inhibiting stem elongation Chloroplast movement Stomatal opening Gene expression Flowering in Arabidopsis
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Blue Light Responses Circadian Rhythms Solar tracking Phototropism Inhibiting stem elongation Chloroplast movement Stomatal opening Gene expression Flowering in Arabidopsis Responses vary in their fluence requirements
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Blue Light Responses Circadian Rhythms Solar tracking Phototropism Inhibiting stem elongation Chloroplast movement Stomatal opening Gene expression Flowering in Arabidopsis Responses vary in their fluence requirements & lag times
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Blue Light Responses Responses vary in their fluence requirements & lag time Stomatal opening is reversible by green light; others aren’t
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Blue Light Responses Responses vary in their fluence requirements & lag time Stomatal opening is reversible by green light; others aren’t Multiple blue receptors with different functions!
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Blue Light Responses Responses vary in their fluence requirements & lag time Stomatal opening is reversible by green light; others aren’t Multiple blue receptors with different functions! Identified by mutants
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Blue Light Responses Responses vary in their fluence requirements & lag time Stomatal opening is reversible by green light; others aren’t Multiple blue receptors with different functions! Identified by mutants, then clone the gene and identify the protein
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Blue Light Responses Responses vary in their fluence requirements & lag time Stomatal opening is reversible by green light; others aren’t Multiple blue receptors with different functions! Identified by mutants, then clone the gene and identify the protein Cryptochromes repress hypocotyl elongation
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Blue Light Responses Cryptochromes repress hypocotyl elongation Stimulate flowering
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Blue Light Responses Cryptochromes repress hypocotyl elongation Stimulate flowering Set the circadian clock (in humans, too!)
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Blue Light Responses Cryptochromes repress hypocotyl elongation Stimulate flowering Set the circadian clock (in humans, too!) Stimulate anthocyanin synthesis
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Blue Light Responses Cryptochromes repress hypocotyl elongation Stimulate flowering Set the circadian clock (in humans, too!) Stimulate anthocyanin synthesis 3 CRY genes
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Blue Light Responses 3 CRY genes All have same basic structure: Photolyase-like domain binds FAD and a pterin (MTHF) that absorbs blue & transfers energy to FAD in photolyase (an enzyme that uses light energy to repair pyr dimers)
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Blue Light Responses 3 CRY genes All have same basic structure: Photolyase-like domain binds FAD and a pterin (MTHF) that absorbs blue & transfers energy to FAD in photolyase (an enzyme that uses light energy to repair pyr dimers) DAS binds COP1 & has nuclear localization signals
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Blue Light Responses 3 CRY genes All have same basic structure: Photolyase-like domain binds FAD and a pterin (MTHF) that absorbs blue & transfers energy to FAD in photolyase (an enzyme that uses light energy to repair pyr dimers) DAS binds COP1 & has nuclear localization signals CRY1 & CRY2 kinase proteins after absorbing blue
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Blue Light Responses 3 CRY genes CRY1 & CRY2 kinase proteins after absorbing blue CRY3 repairs mt & cp DNA!
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Blue Light Responses 3 CRY genes CRY1 regulates blue effects on growth: light-stable Triggers rapid changes in PM potential & growth
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Blue Light Responses 3 CRY genes CRY1 regulates blue effects on growth: light-stable Triggers rapid changes in PM potential & growth Opens anion channels in PM
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Blue Light Responses 3 CRY genes CRY1 regulates blue effects on growth: light-stable Triggers rapid changes in PM potential & growth Opens anion channels in PM Stimulates anthocyanin synthesis
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Blue Light Responses 3 CRY genes CRY1 regulates blue effects on growth: light-stable Triggers rapid changes in PM potential & growth Opens anion channels in PM Stimulates anthocyanin synthesis Entrains the circadian clock
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Blue Light Responses 3 CRY genes CRY1 regulates blue effects on growth: light-stable Triggers rapid changes in PM potential & growth Opens anion channels in PM Stimulates anthocyanin synthesis Entrains the circadian clock Also accumulates in nucleus & interacts with PHY & COP1 to regulate photomorphogenesis, probably by kinasing substrates
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Blue Light Responses 3 CRY genes CRY1 regulates blue effects on growth: light-stable Triggers rapid changes in PM potential & growth Opens anion channels in PM Stimulates anthocyanin synthesis Entrains the circadian clock Also accumulates in nucleus & interacts with PHY & COP1 to regulate photomorphogenesis, probably by kinasing substrates 2. CRY2 controls flowering
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Blue Light Responses 3 CRY genes CRY1 regulates blue effects on growth: light-stable 2. CRY2 controls flowering: little effect on other processes Light-labile
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Blue Light Responses 3 CRY genes CRY1 regulates blue effects on growth: light-stable 2. CRY2 controls flowering: little effect on other processes Light-labile 3. CRY3 enters cp & mito, where binds & repairs DNA!
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Blue Light Responses 3 CRY genes CRY1 regulates blue effects on growth 2. CRY2 controls flowering: little effect on other processes CRY3 enters cp & mito, where binds & repairs DNA! Cryptochromes are not involved in phototropism or stomatal opening!
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Blue Light Responses Cryptochromes are not involved in phototropism or stomatal opening! Phototropins are!
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Blue Light Responses Phototropins are involved in phototropism & stomatal opening! Many names (nph, phot, rpt) since found by several different mutant screens
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Phototropins Many names (nph, phot, rpt) since found by several different mutant screens Mediate blue light-induced growth enhancements
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Phototropins Many names (nph, phot, rpt) since found by several different mutant screens Mediate blue light-induced growth enhancement & blue light-dependent activation of the plasma membrane H+-ATPase in guard cells
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Phototropins Many names (nph, phot, rpt) since found by several different mutant screens Mediate blue light-induced growth enhancement & blue light-dependent activation of the plasma membrane H+-ATPase in guard cells Contain light-activated serine-threonine kinase domain and LOV1 (light-O2-voltage) and LOV2 repeats
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Phototropins Many names (nph, phot, rpt) since found by several different mutant screens Mediate blue light-induced growth enhancement & blue light-dependent activation of the plasma membrane H+-ATPase in guard cells Contain light-activated serine-threonine kinase domain and LOV1 (light-O2-voltage) and LOV2 repeats LOV1 & LOV2 bind FlavinMonoNucleotide cofactors
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Phototropins Many names (nph, phot, rpt) since found by several different mutant screens Mediate blue light-induced growth enhancement & blue light-dependent activation of the plasma membrane H+-ATPase in guard cells Contain light-activated serine-threonine kinase domain and LOV1 (light-O2-voltage) and LOV2 repeats LOV1 & LOV2 bind FlavinMonoNucleotide cofactors After absorbing blue rapidly autophosphorylate & kinase other proteins
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Phototropins After absorbing blue rapidly autophosphorylate & kinase other proteins 1 result = phototropism due to uneven auxin transport
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Phototropins After absorbing blue rapidly autophosphorylate & kinase other proteins 1 result = phototropism due to uneven auxin transport Send more to side away from light!
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Phototropins After absorbing blue rapidly autophosphorylate & kinase other proteins 1 result = phototropism due to uneven auxin transport Send more to side away from light! Phot 1 mediates LF
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Phototropins After absorbing blue rapidly autophosphorylate & kinase other proteins 1 result = phototropism due to uneven auxin transport Send more to side away from light! PHOT 1 mediates LF PHOT2 mediates HIR
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Phototropins 2nd result = stomatal opening via stimulation of guard cell PM proton pump Also requires photosynthesis by guard cells!
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Phototropins 2nd result = stomatal opening via stimulation of guard cell PM proton pump Also requires photosynthesis by guard cells & signaling from xanthophylls
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Phototropins 2nd result = stomatal opening via stimulation of guard cell PM proton pump Also requires photosynthesis by guard cells & signaling from xanthophylls npq mutants don’t make zeaxanthin & lack specific blue response
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Phototropins 2nd result = stomatal opening via stimulation of guard cell PM proton pump Also requires photosynthesis by guard cells & signaling from xanthophylls npq mutants don’t make zeaxanthin & lack specific blue response Basic idea: open when pump in K+
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Phototropins 2nd result = stomatal opening via stimulation of guard cell PM proton pump Also requires photosynthesis by guard cells & signaling from xanthophylls npq mutants don’t make zeaxanthin & lack specific blue response Basic idea: open when pump in K+ Close when pump out K+
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Phototropins Basic idea: open when pump in K+ Close when pump out K+ Control is hideously complicated!
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Phototropins Basic idea: open when pump in K+ Close when pump out K+ Control is hideously complicated! Mainly controlled by blue light
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Phototropins Basic idea: open when pump in K+ Close when pump out K+ Control is hideously complicated! Mainly controlled by blue light, but red also plays role
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Phototropins Basic idea: open when pump in K+ Close when pump out K+ Control is hideously complicated! Mainly controlled by blue light, but red also plays role Light intensity is also important
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Phototropins Mainly controlled by blue light, but red also plays role Light intensity is also important due to effect on [photosynthate] in guard cells
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Phototropins Mainly controlled by blue light, but red also plays role Light intensity is also important due to effect on [photosynthate] in guard cells PHOT1 &2 also help
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Phototropins Mainly controlled by blue light, but red also plays role Light intensity is also important due to effect on [photosynthate] in guard cells PHOT1 &2 also help Main GC blue receptor is zeaxanthin!
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Phototropins Mainly controlled by blue light, but red also plays role Light intensity is also important due to effect on [photosynthate] in guard cells PHOT1 &2 also help Main GC blue receptor is zeaxanthin! Reason for green reversal
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Phototropins Mainly controlled by blue light, but red also plays role Light intensity is also important due to effect on [photosynthate] in guard cells PHOT1 &2 also help Main GC blue receptor is zeaxanthin! Reason for green reversal water stress overrides light!
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Phototropins water stress overrides light: roots make Abscisic Acid: closes stomates & blocks opening regardless of other signals!
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