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Published byViolet Paul Modified over 6 years ago
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Pathogens Agrobacterium tumefaciens: Greg Agrobacterium rhizogenes Pseudomonas syringeae Pseudomonas aeruginosa: Mike Viroids: Bryant DNA viruses RNA viruses: Rob Fungi : Connor oomycetes Nematodes: Chris Symbionts N-fixers Endomycorrhizae Ectomycorrhizae
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Nutrient transport in roots
Move from soil to endodermis in apoplast Move from endodermis to xylem in symplast
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Nutrient transport in roots
Transported into xylem by H+ antiporters, channels,pumps
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Transport to shoot Nutrients move up plant in xylem sap
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Nutrient transport in leaves
Xylem sap moves through apoplast Leaf cells take up what they want
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Nutrient assimilation
Assimilating N and S is very expensive! Reducing NO3- to NH4+ costs 8 e- (1 NADPH + 6 Fd)
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Nutrient assimilation
Assimilating N and S is very expensive! Reducing NO3- to NH4+ costs 8 e- (1 NADPH + 6 Fd) Assimilating NH4+ into amino acids also costs ATP + e-
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Nutrient assimilation
Assimilating N and S is very expensive! Reducing NO3- to NH4+ costs 8 e- (1 NADPH + 6 Fd) Assimilating NH4+ into amino acids also costs ATP + e- Nitrogen fixation costs 16 ATP + 8 e-
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Nutrient assimilation
Assimilating N and S is very expensive! Reducing NO3- to NH4+ costs 8 e- (1 NADPH + 6 Fd) Assimilating NH4+ into amino acids also costs ATP + e- Nitrogen fixation costs 16 ATP + 8 e- SO42- reduction to S2- costs 8 e- + 2ATP
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Nutrient assimilation
Assimilating N and S is very expensive! Reducing NO3- to NH4+ costs 8 e- (1 NADPH + 6 Fd) Assimilating NH4+ into amino acids also costs ATP + e- Nitrogen fixation costs 16 ATP + 8 e- SO42- reduction to S2- costs 8 e- + 2ATP S2- assimilation into Cysteine costs 2 more e- Most explosives are based on N or S!
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Nutrient assimilation
Most explosives are based on N or S! Most nutrient assimilation occurs in source leaves!
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N cycle Must convert N2 to a form that can be assimilated N2 -> NO3- occurs in atmosphere: lightning (8%) & Photochemistry (2%) of annual total fixed Remaining 90% comes from biological fixation to NH4+
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N cycle Soil bacteria denitrify NO3- & NH4+ back to N2 Plants must act fast! Take up NO3- & NH4+ but generally prefer NO3- Main form available due to bacteria
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N assimilation by non-N fixers
Nitrate reductase in cytoplasm reduces NO3- to NO2- NO3- + NADPH = NO2- + NADP+ large enzyme with FAD & Mo cofactors NO2- is imported to plastids & reduced to NH4+ by nitrite reductase
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N assimilation by non-N fixers
NO2- is imported to plastids & reduced to NH4+ by nitrite reductase NO Fdred + 8 H+ = NH Fdox + 2 H2O
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N assimilation by non-N fixers
NO2- is imported to plastids & reduced to NH4+ by nitrite reductase NO Fdred + 8 H+ = NH Fdox + 2 H2O Regulated at NO3- reductase; always << NO2- reductase NO2- is toxic!
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N assimilation by non-N fixers
Regulated at NO3- reductase; always << NO2- reductase NO2- is toxic! NR induced by light & nitrate
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N assimilation by non-N fixers
Regulated at NO3- reductase; always << NO2- reductase NO2- is toxic! NR induced by light & nitrate Regulated by kinase in dark, dephosphorylation in day
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NH4 assimilation GS -> GOGAT Glutamate + NH4+ + ATP <=> Glutamine + ADP +Pi
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GS -> GOGAT Glutamate + NH4+ + ATP <=> Glutamine + ADP +Pi Glutamine + a-ketoglutarate + NADH/2 Fdred <=> 2 Glutamate + NAD+/ 2 Fdox
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GS -> GOGAT Glutamate + NH4+ + ATP <=> Glutamine + ADP +Pi Glutamine + a-ketoglutarate + NADH/2 Fdred <=> 2 Glutamate + NAD+/ 2 Fdox 3. Fd GOGAT lives in source cp
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GS -> GOGAT Fd GOGAT lives in source cp NADH GOGAT lives in sinks
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GS -> GOGAT Glutamate + NH4+ + ATP <=> Glutamine + ADP +Pi Glutamine + a-ketoglutarate + NADH/2 Fdred <=> 2 Glutamate + NAD+/ 2 Fdox 3. Use glutamate to make other a.a. by transamination
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GS -> GOGAT 3. Use glutamate to make other a.a. by transamination Glutamate, aspartate & alanine can be converted to the other a.a.
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S assimilation SO42- comes from weathering or from rain: now an important source! Main thing that makes rain acid!
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S assimilation S is used in cysteine & methionine
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S assimilation S is used in cysteine & methionine Also used in CoA, S-adenosylmethionine
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S assimilation S is used in cysteine & methionine Also used in CoA, S-adenosylmethionine Also used in sulphoquinovosyl-diacylglycerol
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S assimilation S is used in cysteine & methionine Also used in CoA, S-adenosylmethionine Also used in sulphoquinovosyl-diacylglycerol And in many storage compounds: eg allicin (garlic)
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S assimilation SO42- comes from weathering or from rain: now an important source! Main thing that makes rain acid! Some bacteria use SO42- as e- acceptor -> H2S
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S assimilation SO42- comes from weathering or from rain: now an important source! Main thing that makes rain acid! Some bacteria use SO42- as e- acceptor -> H2S Some photosynthetic bacteria use reduced S as e- donor!
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S assimilation SO42- comes from weathering or from rain: now an important source! Main thing that makes rain acid! Some bacteria use SO42- as e- acceptor -> H2S Some photosynthetic bacteria use reduced S as e- donor! Now that acid rain has declined in N. Europe Brassica & wheat need S in many places
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S assimilation SO4 2- is taken up by roots & transported to leaves in xylem Most is reduced in cp
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S assimilation SO4 2- is taken up by roots & transported to leaves in xylem Most is reduced in cp 1. add SO4 2- to ATP -> APS
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S assimilation add SO4 2- to ATP -> APS Transfer S to Glutathione -> S-sulfoglutathione
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S assimilation add SO4 2- to ATP -> APS Transfer S to Glutathione -> S-sulfoglutathione S-sulfoglutathione + GSH -> SO32- + GSSG
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S assimilation add SO4 2- to ATP -> APS Transfer S to Glutathione -> S-sulfoglutathione S-sulfoglutathione + GSH -> SO32- + GSSG Sulfite + 6 Fd -> Sulfide
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S assimilation add SO4 2- to ATP -> APS Transfer S to Glutathione -> S-sulfoglutathione S-sulfoglutathione + GSH -> SO32- + GSSG Sulfite + 6 Fd -> Sulfide Sulfide + O-acetylserine -> cysteine + acetate O-acetylserine was made from serine + acetyl-CoA
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S assimilation Most cysteine is converted to glutathione or methionine
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S assimilation Most cysteine is converted to glutathione or methionine Glutathione is main form exported
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S assimilation Most cysteine is converted to glutathione or methionine Glutathione is main form exported Also used to make many other S-compounds
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S assimilation Most cysteine is converted to glutathione or methionine Glutathione is main form exported Also used to make many other S-compounds Methionine also has many uses besides protein synthesis
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S assimilation Most cysteine is converted to glutathione or methionine Cys + homoserine -> cystathione
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S assimilation Most cysteine is converted to glutathione or methionine Cys + homoserine -> cystathione Cystathione -> homocysteine + Pyruvate + NH4+
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S assimilation Most cysteine is converted to glutathione or methionine Cys + homoserine -> cystathione Cystathione -> homocysteine + Pyruvate + NH4+ Homocysteine + CH2=THF -> Met + THF 80% of met is converted to S-adenosylmethionine & used for biosyntheses
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S assimilation Most cysteine is converted to glutathione or methionine Glutathione is made enzymatically! Glutamate + Cysteine -> g-glutamyl cysteine
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S assimilation Glutathione (GluCysGly) is made enzymatically! Glutamate + Cysteine -> g-glutamyl cysteine g-glutamyl cysteine + glycine -> glutathionine
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S assimilation Glutathione (GluCysGly) is made enzymatically! Glutamate + Cysteine -> g-glutamyl cysteine g-glutamyl cysteine + glycine -> glutathionine Glutathione is precursor for many chemicals, eg phytochelatins
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S assimilation Glutathione (GluCysGly) is made enzymatically! Glutamate + Cysteine -> g-glutamyl cysteine g-glutamyl cysteine + glycine -> glutathionine Glutathione is precursor for many chemicals, eg phytochelatins SAM & glutathione are also precursors for many cell wall components
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Plant Growth Size & shape depends on cell # & cell size
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Plant Growth Size & shape depends on cell # & cell size Decide when,where and which way to divide
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Plant Growth Size & shape depends on cell # & cell size Decide which way to divide & which way to elongate Periclinal = perpendicular to surface
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Plant Growth Size & shape depends on cell # & cell size Decide which way to divide & which way to elongate Periclinal = perpendicular to surface: get longer
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Plant Growth Size & shape depends on cell # & cell size Decide which way to divide & which way to elongate Periclinal = perpendicular to surface: get longer Anticlinal = parallel to surface
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Plant Growth Size & shape depends on cell # & cell size Decide which way to divide & which way to elongate Periclinal = perpendicular to surface: get longer Anticlinal = parallel to surface: add more layers
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Plant Growth Decide which way to divide & which way to elongate Periclinal = perpendicular to surface: get longer Anticlinal = parallel to surface: add more layers Now must decide which way to elongate
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Plant Growth Decide which way to divide & which way to elongate Periclinal = perpendicular to surface: get longer Anticlinal = parallel to surface: add more layers Now must decide which way to elongate: which walls to stretch
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Plant Cell Walls and Growth
Carbohydrate barrier surrounding cell Protects & gives cell shape
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Plant Cell Walls and Growth
Carbohydrate barrier surrounding cell Protects & gives cell shape 1˚ wall made first mainly cellulose Can stretch!
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Plant Cell Walls and Growth
Carbohydrate barrier surrounding cell Protects & gives cell shape 1˚ wall made first mainly cellulose Can stretch! 2˚ wall made after growth stops Lignins make it tough
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Plant Cell Walls and Growth
1˚ wall made first mainly cellulose Can stretch! Control elongation by controlling orientation of cell wall fibers as wall is made
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Plant Cell Walls and Growth
1˚ wall made first mainly cellulose Can stretch! Control elongation by controlling orientation of cell wall fibers as wall is made 1˚ walls = 25% cellulose, 25% hemicellulose, 35% pectin, 5% protein (but highly variable)
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Plant Cell Walls and Growth
1˚ walls = 25% cellulose, 25% hemicellulose, 35% pectin, 5% protein (but highly variable) Cellulose: ordered chains made of glucose linked b 1-4
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Plant Cell Walls and Growth
1˚ walls = 25% cellulose, 25% hemicellulose, 35% pectin, 5% protein (but highly variable) Cellulose: ordered chains made of glucose linked b 1-4 Cross-link with neighbors to form strong, stable fibers
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Plant Cell Walls and Growth
Cellulose: ordered chains made of glucose linked b 1-4 Cross-link with neighbors to form strong, stable fibers Made by enzyme embedded in the plasma membrane
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Plant Cell Walls and Growth
Cellulose: ordered chains made of glucose linked b 1-4 Cross-link with neighbors to form strong, stable fibers Made by enzyme embedded in the plasma membrane Guided by cytoskeleton
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Plant Cell Walls and Growth
Cellulose: ordered chains made of glucose linked b 1-4 Cross-link with neighbors to form strong, stable fibers Made by enzyme embedded in the plasma membrane Guided by cytoskeleton Cells with poisoned µtubules are misshapen
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Plant Cell Walls and Growth
Cellulose: ordered chains made of glucose linked b 1-4 Cross-link with neighbors to form strong, stable fibers Made by enzyme embedded in the plasma membrane Guided by cytoskeleton Cells with poisoned µtubules are misshapen Other wall chemicals are made in Golgi & secreted
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Plant Cell Walls and Growth
Cellulose: ordered chains made of glucose linked b 1-4 Cross-link with neighbors to form strong, stable fibers Made by enzyme embedded in the plasma membrane Guided by cytoskeleton Cells with poisoned µtubules are misshapen Other wall chemicals are made in Golgi & secreted Only cellulose pattern is tightly controlled
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Plant Cell Walls and Growth
Cellulose pattern is tightly controlled 6 CES enzymes form a “rosette”: each makes 6 chains -> 36/fiber
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Plant Cell Walls and Growth
Cellulose pattern is tightly controlled 6 CES enzymes form a “rosette”: each makes 6 chains -> 36/fiber Rosettes are guided by microtubules
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Plant Cell Walls and Growth
Cellulose pattern is tightly controlled 6 CES enzymes form a “rosette”: each makes 6 chains Rosettes are guided by microtubules Deposition pattern determines direction of elongation
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Plant Cell Walls and Growth
Cellulose pattern is tightly controlled Deposition pattern determines direction of elongation New fibers are perpendicular to growth direction, yet fibers form a mesh
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Plant Cell Walls and Growth
New fibers are perpendicular to growth direction, yet fibers form a mesh Multinet hypothesis: fibers reorient as cell elongates Old fibers are anchored so gradually shift as cell grows
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Plant Cell Walls and Growth
New fibers are perpendicular to growth direction, yet fibers form a mesh Multinet hypothesis: fibers reorient as cell elongates Old fibers are anchored so gradually shift as cell grows Result = mesh
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