1. 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

2. Nutrient transport in roots
Move from soil to endodermis in apoplast
Move from endodermis to xylem in symplast

3. Nutrient transport in roots
Transported into xylem by H+ antiporters, channels,pumps

4. Transport to shoot
Nutrients move up
plant in xylem sap

5. Nutrient transport in leaves
Xylem sap moves through apoplast
Leaf cells take up what
they want

6. Nutrient assimilation
Assimilating N and S is
very expensive!
Reducing NO3- to NH4+
costs 8 e- (1 NADPH +
6 Fd)

7. 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-

8. 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-

9. 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

10. 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!

11. Nutrient assimilation
Most explosives are based on N or S!
Most nutrient assimilation occurs in source leaves!

12. 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+

13. 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

14. 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

15. 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

16. 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!

17. N assimilation by non-N fixers
Regulated at NO3- reductase; always << NO2- reductase
NO2- is toxic!
NR induced by light & nitrate

18. 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

19. NH4 assimilation
GS -> GOGAT
Glutamate + NH4+ + ATP <=> Glutamine + ADP +Pi

20. GS -> GOGAT
Glutamate + NH4+ + ATP <=> Glutamine + ADP +Pi
Glutamine + a-ketoglutarate + NADH/2 Fdred <=>
2 Glutamate + NAD+/ 2 Fdox

21. 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

22. GS -> GOGAT
Fd GOGAT lives in source cp
NADH GOGAT lives in sinks

23. 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

24. GS -> GOGAT
3. Use glutamate to make other a.a. by transamination
Glutamate, aspartate & alanine can be converted to the other a.a.

25. S assimilation
SO42- comes from weathering or from rain: now an important source! Main thing that makes rain acid!

26. S assimilation
S is used in cysteine & methionine

27. S assimilation
S is used in cysteine & methionine
Also used in CoA, S-adenosylmethionine

28. S assimilation
S is used in cysteine & methionine
Also used in CoA, S-adenosylmethionine
Also used in sulphoquinovosyl-diacylglycerol

29. 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)

30. 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

31. 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!

32. 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

33. S assimilation
SO4 2- is taken up by roots &
transported to leaves in xylem
Most is reduced in cp

34. 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

35. S assimilation
add SO4 2- to ATP -> APS
Transfer S to Glutathione -> S-sulfoglutathione

36. S assimilation
add SO4 2- to ATP -> APS
Transfer S to Glutathione -> S-sulfoglutathione
S-sulfoglutathione + GSH -> SO32- + GSSG

37. S assimilation
add SO4 2- to ATP -> APS
Transfer S to Glutathione -> S-sulfoglutathione
S-sulfoglutathione + GSH -> SO32- + GSSG
Sulfite + 6 Fd -> Sulfide

38. 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

39. S assimilation
Most cysteine is converted to
glutathione or methionine

40. S assimilation
Most cysteine is converted to
glutathione or methionine
Glutathione is main form
exported

41. S assimilation
Most cysteine is converted to
glutathione or methionine
Glutathione is main form
exported
Also used to make many other
S-compounds

42. 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

43. S assimilation
Most cysteine is converted to glutathione or methionine
Cys + homoserine -> cystathione

44. S assimilation
Most cysteine is converted to glutathione or methionine
Cys + homoserine -> cystathione
Cystathione -> homocysteine + Pyruvate + NH4+

45. 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

46. S assimilation
Most cysteine is converted to glutathione or methionine
Glutathione is made enzymatically!
Glutamate + Cysteine -> g-glutamyl cysteine

47. S assimilation
Glutathione (GluCysGly) is made enzymatically!
Glutamate + Cysteine -> g-glutamyl cysteine
g-glutamyl cysteine + glycine -> glutathionine

48. 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

49. 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

50. Plant Growth
Size & shape depends on cell # & cell size

51. Plant Growth
Size & shape depends on cell # & cell size
Decide when,where and which way to divide

52. Plant Growth
Size & shape depends on cell # & cell size
Decide which way to divide & which way to elongate
Periclinal = perpendicular to surface

53. Plant Growth
Size & shape depends on cell # & cell size
Decide which way to divide & which way to elongate
Periclinal = perpendicular to surface: get longer

54. 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

55. 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

56. 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

57. 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

58. Plant Cell Walls and Growth
Carbohydrate barrier
surrounding cell
Protects & gives cell shape

59. Plant Cell Walls and Growth
Carbohydrate barrier
surrounding cell
Protects & gives cell shape
1˚ wall made first
mainly cellulose
Can stretch!

60. 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

61. 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

62. 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)

63. 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

64. 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

65. 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

66. 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

67. 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

68. 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

69. 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

70. Plant Cell Walls and Growth
Cellulose pattern is tightly controlled
6 CES enzymes form a “rosette”: each makes 6 chains -> 36/fiber

71. 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

72. 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

73. 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

74. 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

75. 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