Help needed for the Art & Science Day at the Chester Street Elementary school 110 Chester St, Kingston 12- 3:30 on Tuesday, March 22.

Plant Growth & Development
3 stages Embryogenesis Fertilization to seed Plant Growth & Development 3 stages Embryogenesis Fertilization to seed 2. Vegetative growth Juvenile stage Germination to adult "phase change" marks transition 3. Reproductive development Make flowers, can reproduce sexually

Senescence Shoot apical meristem now starts making new organ: flowers, with many new structures & cell types Eventually petals, etc senesce = genetically programmed cell death: controlled by specific genes

Senescence Eventually petals, etc senesce = genetically programmed cell death: controlled by specific genes Also seen in many other cases: deciduous leaves in fall, annual plants, older trees

Senescence Induce specific senescence-associated genes ; eg DNAses, proteases, lipases Also seen during xylem formation: when cell wall is complete cell kills itself

Senescence Also seen during xylem formation: when cell wall is complete cell kills itself Also seen as wound response: hypersensitive response Cells surrounding the wound kill themselves

Senescence Also seen during xylem formation: when cell wall is complete cell kills itself Also seen as wound response: hypersensitive response Cells surrounding the wound kill themselves Some mutants do this w/o wound -> is controlled by genes!

Light regulation of Plant Development
Plants use light as food and information Use information to control development

Plants use light as food and information Use information to control development germination

Plants use light as food and information Use information to control development Germination Photomorphogenesis vs skotomorphogenesis

Plants use light as food and information Use information to control development Germination Photomorphogenesis vs skotomorphogenesis Sun/shade & shade avoidance

Germination Morphogenesis Sun/shade & shade avoidance Flowering

Germination Morphogenesis Sun/shade & shade avoidance Flowering Senescence

Light regulation of growth
Plants sense Light quantity

Plants sense Light quantity Light quality (colors)

Plants sense Light quantity Light quality (colors) Light duration

Plants sense Light quantity Light quality (colors) Light duration Direction it comes from

Plants sense Light quantity Light quality (colors) Light duration Direction it comes from Have photoreceptors that sense specific wavelengths

Early work: Darwins showed blue light controls phototropism

Early work: Darwins : blue light controls phototropism Duration = photoperiodism (Garner and Allard,1920) Maryland Mammoth tobacco flowers in the S but not in N

Early work: Darwins : blue light controls phototropism Duration = photoperiodism (Garner and Allard,1920) Maryland Mammoth tobacco flowers in the S but not in N = short-day plant (SDP)

Duration = photoperiodism (Garner and Allard,1920) Maryland Mammoth tobacco flowers in the S but not in N = short-day plant (SDP) Measures night! 30" flashes during night stop flowers

Duration = photoperiodism (Garner and Allard,1920) Maryland Mammoth tobacco flowers in the S but not in N = short-day plant (SDP) Measures night! 30" flashes during night stop flowers LDP plants such as Arabidopsis need long days to flower

Duration = photoperiodism (Garner and Allard,1920) Maryland Mammoth tobacco flowers in the S but not in N = short-day plant (SDP) Measures night! 30" flashes during night stop flowers LDP plants such as Arabidopsis need long days to flower SDP flower in fall, LDP flower in spring, neutral flower when ready

Measures night! 30" flashes during night stop flowers LDP plants such as Arabidopsis need long days to flower SDP flower in fall, LDP flower in spring, neutral flower when ready Next : color matters! Red light works best for flowering

Next : color matters! Red light (666 nm) works best for flowering & for germination of many seeds!

Next : color matters! Red light (666 nm) works best for flowering & for germination of many seeds! But, Darwins showed blue works best for phototropism!

Next : color matters! Red light (666 nm)works best for flowering & for germination of many seeds! But, Darwin showed blue works best for phototropism! Different photoreceptor!

But, Darwin showed blue works best for phototropism! Different photoreceptor! Red light (666 nm) promotes germination Far red light (>700 nm) blocks germination

Red light (666 nm) promotes germination Far red light (>700 nm) blocks germination After alternate R/FR flashes last flash decides outcome

Red light (666 nm) promotes germination Far red light (>700 nm) blocks germination After alternate R/FR flashes last flash decides outcome Seeds don't want to germinate in the shade!

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

Red light (666 nm) promotes germination Far red light (730 nm) blocks germination After alternate R/FR color of final flash decides outcome Pigment is photoreversible! -> helped purify it! Looked for pigment that absorbs first at 666 nm, then 730

Phytochrome Red light (666 nm) promotes germination Far red light (730 nm) blocks germination After alternate R/FR color of final flash decides outcome Pigment is photoreversible! -> helped purify it! Looked for pigment that absorbs first at 666 nm, then 730

Phytochrome Red light (666 nm) promotes germination Far red light (730 nm) blocks germination After alternate R/FR color of final flash decides outcome Pigment is photoreversible! -> helped purify it! Looked for pigment that absorbs first at 666 nm, then 730 Made as inactive cytoplasmic Pr that absorbs at 666 nm

Phytochrome Made as inactive cytoplasmic Pr that absorbs at 666 nm or in blue Converts to active Pfr that absorbs far red (730nm)

Types of Phytochrome Responses
Two categories based on speed Rapid biochemical events Morphological changes

Two categories based on speed Rapid biochemical events Morphological changes Lag time also varies from minutes to weeks

Two categories based on speed Rapid biochemical events Morphological changes Lag time also varies from minutes to weeks: numbers of steps after Pfr vary

Lag time also varies from minutes to weeks: numbers of steps after Pfr vary "Escape time" until a response can no longer be reversed by FR also varies

Lag time also varies from minutes to weeks: numbers of steps after Pfr vary "Escape time" until a response can no longer be reversed by FR also varies: time taken for Pfr to do its job Conclusions: phytochrome acts on many processes in many ways

Two categories based on speed 3 classes based on fluence (amount of light needed) VLF:induced by 0.1 nmol/m-2 , 50nmol/m-2

Two categories based on speed 3 classes based on fluence (amount of light needed) VLF:induced by 0.1 nmol/m-2 , 50nmol/m-2 Changes 0.02% of Pr to Pfr

3 classes based on fluence (amount of light needed) VLF:induced by 0.1 nmol/m-2 , 50nmol/m-2 Changes 0.02% of Pr to Pfr Are not FR-reversible!

3 classes based on fluence (amount of light needed) VLF:induced by 0.1 nmol/m-2 , 50nmol/m-2 Changes 0.02% of Pr to Pfr Are not FR-reversible! But action spectrum same as Pr

3 classes based on fluence (amount of light needed) VLF:induced by 0.1 nmol/m-2 , 50nmol/m-2 Changes 0.02% of Pr to Pfr Are not FR-reversible! But action spectrum same as Pr Induced by FR!

3 classes based on fluence (amount of light needed) VLF:induced by 0.1 nmol/m-2 , 50nmol/m-2 Changes 0.02% of Pr to Pfr Are not FR-reversible! But action spectrum same as Pr Induced by FR! Obey law of reciprocity: 1 nmol/m-2 x 100 s = 100 nmol/m-2 x 1 sec

3 classes based on fluence (amount of light needed) VLF:induced by 0.1 nmol/m-2 , 50nmol/m-2 Changes 0.02% of Pr to Pfr Are not FR-reversible! But action spectrum same as Pr Induced by FR! Obey law of reciprocity: 1 nmol/m-2 x 100 s = 100 nmol/m-2 x 1 sec Examples: Cab gene induction, oat coleoptile growth

3 classes based on fluence (amount of light needed) VLF:induced by 0.1 nmol/m-2 , 50nmol/m-2 Changes 0.02% of Pr to Pfr Are not FR-reversible! But action spectrum same as Pr Induced by FR! Obey law of reciprocity: 1 nmol/m-2 x 100 s = 100 nmol/m-2 x 1 sec Examples: Cab gene induction, oat coleoptile growth 2. LF: induced by 1 µmol/m-2, 1000 µmol/m-2

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 Are FR-reversible!

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 Are FR-reversible! Need > 3% Pfr

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 Are FR-reversible! Need > 3% Pfr Obey law of reciprocity

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 Are FR-reversible! Need > 3% Pfr Obey law of reciprocity Examples : Lettuce seed Germination, mustard photomorphogenesis, inhibits flowering in SDP

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 Are FR-reversible! Need > 3% Pfr Obey law of reciprocity Examples : Lettuce seed Germination, mustard photomorphogenesis, inhibits flowering in SDP 3. HIR: require prolonged exposure to higher fluence

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

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 Disobey law of reciprocity Are not FR-reversible!

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 Disobey law of reciprocity Are not FR-reversible! Some are induced by FR!

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 Disobey law of reciprocity Are not FR-reversible! Some are induced by FR! Examples: inhibition of hypocotyl elongation in many seedlings, Anthocyanin synthesis

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 Disobey law of reciprocity Are not FR-reversible! Some are induced by FR! Examples: inhibition of hypocotyl elongation in many seedlings, Anthocyanin synthesis Different responses = Different phytochromes

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

Different responses = Different phytochromes: 3 in rice, 5 in Arabidopsis PHYA mediates VLF and HIR due to FR

Different responses = Different phytochromes: 3 in rice, 5 in Arabidopsis PHYA mediates VLF and HIR due to FR Very labile in light

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

PHYA mediates VLF and HIR due to FR Very labile in light 2. PHYB mediates LF and HIR due to R Stable in light 3. Roles of PHYs C, D & E not so clear

PHYA mediates VLF and HIR due to FR Very labile in light 2. PHYB mediates LF and HIR due to R Stable in light 3. Roles of PHYs C, D & E not so clear PHYA & PHYB are often antagonistic.

PHYA & PHYB are often antagonistic. In sunlight PHYB mainly controls development

PHYA & PHYB are often antagonistic. In sunlight PHYB mainly controls development In shade PHYA 1st controls development, since FR is high

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"

Phytochrome Pr has cis-chromophore

Phytochrome Pr has cis-chromophore Red converts it to trans = active shape

Phytochrome Pr has cis-chromophore Red converts it to trans = active shape Far-red reverts it to cis

Phytochrome Pfr is a protein kinase: acts by kinasing key proteins some stays in cytoplasm & activates ion pumps

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

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

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

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

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

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

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

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

Phytochrome 20% of genes are light-regulated Protein degradation is important for light regulation

Phytochrome 20% of genes are light-regulated Protein degradation is important for light regulation Cop mutants can’t degrade specific proteins

Phytochrome Protein degradation is important for light regulation Cop mutants can’t degrade specific proteins COP1/SPA targets specific transcription factors for degradation

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

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

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

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!

Other Phytochrome Responses
In shade avoidance FR stimulates IAA synthesis from trp! Occurs in < 1 hour

In shade avoidance FR stimulates IAA synthesis from trp! Occurs in < 1 hour Also occurs in response to endogenous ethylene!

Flowering under short days is controlled via protein deg COP & CUL4 mutants flower early

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

Circadian rhythms Many plant responses, some developmental, some physiological, show circadian rhythms

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

Circadian rhythms Many plant responses show circadian rhythms Once entrained, continue in constant dark

Circadian rhythms Many plant responses show circadian rhythms Once entrained, continue in constant dark, or light

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

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!

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

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

Circadian rhythms Light & TOC1 activate LHY & CCA1 at dawn LHY & CCA1 repress TOC1 in day, so they decline too

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)

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

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

Blue Light Responses Circadian Rhythms

Blue Light Responses Circadian Rhythms Solar tracking

Blue Light Responses Circadian Rhythms Solar tracking Phototropism

Blue Light Responses Circadian Rhythms Solar tracking Phototropism Inhibiting stem elongation

Blue Light Responses Circadian Rhythms Solar tracking Phototropism Inhibiting stem elongation Chloroplast movement

Blue Light Responses Circadian Rhythms Solar tracking Phototropism Inhibiting stem elongation Chloroplast movement Stomatal opening

Blue Light Responses Circadian Rhythms Solar tracking Phototropism Inhibiting stem elongation Chloroplast movement Stomatal opening Gene expression

Blue Light Responses Circadian Rhythms Solar tracking Phototropism Inhibiting stem elongation Chloroplast movement Stomatal opening Gene expression Flowering in Arabidopsis

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

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

Blue Light Responses Responses vary in their fluence requirements & lag time Stomatal opening is reversible by green light; others aren’t

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!

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

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

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

Blue Light Responses Cryptochromes repress hypocotyl elongation Stimulate flowering

Blue Light Responses Cryptochromes repress hypocotyl elongation Stimulate flowering Set the circadian clock (in humans, too!)

Blue Light Responses Cryptochromes repress hypocotyl elongation Stimulate flowering Set the circadian clock (in humans, too!) Stimulate anthocyanin synthesis

Blue Light Responses Cryptochromes repress hypocotyl elongation Stimulate flowering Set the circadian clock (in humans, too!) Stimulate anthocyanin synthesis 3 CRY genes

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)

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

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

Blue Light Responses 3 CRY genes CRY1 & CRY2 kinase proteins after absorbing blue CRY3 repairs mt & cp DNA!

Blue Light Responses 3 CRY genes CRY1 regulates blue effects on growth: light-stable Triggers rapid changes in PM potential & growth

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

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

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

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

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

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

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!

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!

Blue Light Responses Cryptochromes are not involved in phototropism or stomatal opening! Phototropins are!

Blue Light Responses Phototropins are involved in phototropism & stomatal opening! Many names (nph, phot, rpt) since found by several different mutant screens

Phototropins Many names (nph, phot, rpt) since found by several different mutant screens Mediate blue light-induced growth enhancements

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

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

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

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

Phototropins After absorbing blue rapidly autophosphorylate & kinase other proteins 1 result = phototropism due to uneven auxin transport

Phototropins After absorbing blue rapidly autophosphorylate & kinase other proteins 1 result = phototropism due to uneven auxin transport Send more to side away from light!

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

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

Phototropins 2nd result = stomatal opening via stimulation of guard cell PM proton pump Also requires photosynthesis by guard cells!

Phototropins 2nd result = stomatal opening via stimulation of guard cell PM proton pump Also requires photosynthesis by guard cells & signaling from xanthophylls

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

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+

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+

Phototropins Basic idea: open when pump in K+ Close when pump out K+ Control is hideously complicated!

Phototropins Basic idea: open when pump in K+ Close when pump out K+ Control is hideously complicated! Mainly controlled by blue light

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

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

Phototropins Mainly controlled by blue light, but red also plays role Light intensity is also important due to effect on [photosynthate] in guard cells

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

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!

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

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!

Phototropins water stress overrides light: roots make Abscisic Acid: closes stomates & blocks opening regardless of other signals!

Help needed for the Art & Science Day at the Chester Street Elementary school 110 Chester St, Kingston 12- 3:30 on Tuesday, March 22.

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Help needed for the Art & Science Day at the Chester Street Elementary school 110 Chester St, Kingston 12- 3:30 on Tuesday, March 22.

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Presentation on theme: "Help needed for the Art & Science Day at the Chester Street Elementary school 110 Chester St, Kingston 12- 3:30 on Tuesday, March 22."— Presentation transcript:

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