Course Plan We will study effects of soil and stresses on plant secondary products and see where it leads us 1.Learn more about plant secondary products Why do they make them? When do they make them? Where do they make them?

Pick some plants to study Capsicum (Chiles) = capsaicin Nicotiana (Tobacco) = nicotine Onions (Allium cepa)?= syn-Propanethial-S-oxide Garlic (Allium sativum)?= Alliin Radishes (Raphanus sativus) = glucosinolatesRaphanus Mustard (Brassica juncea) = glucosinolates Basil (Ocimum basilicum) = eugenol (and others) Cilantro (Coriandrum sativum) = lots of candidates! Peppermint (Mentha × piperita) = menthol + many Catnip (Nepeta cataria) = nepetalactone Dill = dillapiole Purslane (Portulaca oleracea)= omega-3 fatty acids Brassica rapa = glucosinolates

Plant Stress Won Senator Proxmire’s “Golden Fleece” award for wasteful government spending 1.Water? 2.Nutrients? 3.Environment? Temp? Pollution? Ozone, other gases? Herbicides, eg Round-Up, Atrazine? Insects and other herbivores? Pathogens = bacteria, viruses, fungi

Plant Stress Next assignment: presenting a plant stressor, what is known about it, and why it might affect plant 2˚ compounds in an ~ 10 minute presentation? Alternative: presenting another good plant/stressor response to study and why we should choose it over the ones already presented.

Mineral Nutrition Macronutrients: CHOPKNSCaFeMgBNaCl Ca: signaling, middle lamella, cofactor Fe: cofactor Mg: cofactor mobile in plant, so shows first in old leaves

Mineral Nutrition Micronutrients: BNaCl others include Cu, Zn, Mn B: cell elongation. NA metabolism Na: PEP regeneration, K substitute Cl: water-splitting, osmotic balance Cu: cofactor immobile in plant, so shows first in young leaves

Plant food 2.6% ammoniacal nitrogen 4.4% nitrate nitrogen 9% phosphorus 5% potassium calcium (2%) magnesium (0.5%) sulfur (0.05%) boron (0.02%) chlorine (0.1%) cobalt (0.0015%) copper (0.05%) iron (0.1%) manganese (0.05%) molybdenum (0.0009%) nickel (0.0001%) sodium (0.10%) zinc (0.05%)

Mineral Nutrition Soil nutrients Amounts & availability vary PSU extension Text

Mineral Nutrition Soil nutrients Amounts & availability vary Many are immobile, eg P, Fe

Mineral Nutrition Soil nutrients Amounts & availability vary Many are immobile, eg P, Fe Mobile nutrients come with soil H 2 O

Mineral Nutrition Soil nutrients Amounts & availability vary Many are immobile, eg P, Fe Mobile nutrients come with soil H 2 O Immobiles must be “mined” Root hairs get close

Mineral Nutrition Immobile nutrients must be “mined” Root hairs get close Mycorrhizae get closer

Mineral Nutrition Immobile nutrients must be mined Root hairs get close Mycorrhizae get closer Solubility varies w pH

Mineral Nutrition Solubility varies w pH 5.5 is best compromise

Mineral Nutrition Solubility varies w pH 5.5 is best compromise Plants alter roots to aid uptake

Mineral Nutrition Nutrients in soil Plants alter roots to aid uptake Also use symbionts Mycorrhizal fungi help: especially with P

Mineral Nutrition Also use symbionts Mycorrhizal fungi help: especially with P P travels poorly: fungal hyphae are longer & thinner

Mineral Nutrition Also use symbionts Mycorrhizal fungi help: especially with P P travels poorly: fungal hyphae are longer & thinner Fungi give plants nutrients

Mineral Nutrition Also use symbionts Mycorrhizal fungi help: especially with P P travels poorly: fungal hyphae are longer & thinner Fungi give plants nutrients Plants feed them sugar

Mineral Nutrition Also use symbionts Mycorrhizal fungi help: especially with P P travels poorly: fungal hyphae are longer & thinner Fungi give plants nutrients Plants feed them sugar Ectomycorrhizae surround root: only trees, esp. conifers

Mineral Nutrition Ectomycorrhizae surround root: only trees, esp. conifers release nutrients into apoplast to be taken up by roots

Mineral Nutrition Ectomycorrhizae surround root: trees release nutrients into apoplast to be taken up by roots Endomycorrhizae invade root cells: Vesicular/Arbuscular Most angiosperms, especially in nutrient-poor soils

Mineral Nutrition Endomycorrhizae invade root cells: Vesicular/Arbuscular Most angiosperms, especially in nutrient-poor soils May deliver nutrients into symplast

Rhizosphere Endomycorrhizae invade root cells: Vesicular/Arbuscular Most angiosperms, especially in nutrient-poor soils May deliver nutrients into symplast Or may release them when arbuscule dies

Rhizosphere Endomycorrhizae invade root cells: Vesicular/Arbuscular Most angiosperms, especially in nutrient-poor soils Deliver nutrients into symplast or release them when arbuscule dies Also find bacteria, actinomycetes, protozoa associated with root surface = rhizosphere

Rhizosphere Also find bacteria, actinomycetes, protozoa associated with root surface = rhizosphere Plants feed them lots of C!

Rhizosphere Also find bacteria, actinomycetes, protozoa associated with root surface = rhizosphere Plants feed them lots of C! They help make nutrients available

Rhizosphere Also find bacteria, actinomycetes, protozoa associated with root surface = rhizosphere Plants feed them lots of C! They help make nutrients available N-fixing bacteria supply N to many plant spp

N assimilation by N fixers Exclusively performed by prokaryotes Dramatically improve the growth of many plants

N assimilation by N fixers Exclusively done by prokaryotes Most are free-living in soil or water

N assimilation by N fixers Exclusively done by prokaryotes Most are free-living in soil or water Some form symbioses with plants

N assimilation by N fixers Exclusively done by prokaryotes Most are free-living in soil or water Some form symbioses with plants Legumes are best-known, but many others including mosses, ferns, lichens

N assimilation by N fixers Exclusively done by prokaryotes Most are free-living in soil or water Some form symbioses with plants Legumes are best-known, but many others including mosses, ferns, lichens Also have associations where N-fixers form films on leaves or roots and are fed by plant

N assimilation by N fixers Exclusively done by prokaryotes Also have associations where N-fixers form films on leaves or roots and are fed by plant All must form O 2 -free environment for nitrogenase

N assimilation by N fixers All must form O 2 -free environment for nitrogenase O 2 binds & inactivates electron -transfer sites

N assimilation by N fixers O 2 binds & inactivates electron -transfer sites Heterocysts lack PSII, have other mechs to lower O 2

N assimilation by N fixers Heterocysts lack PSII, have other mechs to lower O 2 Nodules have special structure + leghemoglobin to protect from O 2

Nodule formation Nodules have special structure + leghemoglobin to protect from O 2 Bacteria induce the plant to form nodules

Nodule formation Bacteria induce the plant to form nodules 1.Root hairs secrete chemicals that attract N-fixers

Nodule formation Bacteria induce the plant to form nodules 1.Root hairs secrete chemicals that attract N-fixers 2.Bacteria secrete Nod factors that induce root hair to coil up. Nod factors determine species-specificity

Nodule formation 1.Root hairs secrete chemicals that attract N-fixers 2.Bacteria secrete Nod factors that induce root hair to coil up. Nod factors determine species-specificity 3.Nod factors induce degradation of root cell wall

Nodule formation 3.Nod factors induce degradation of root cell wall 4.Plant forms "infection thread"=internal protusion of plasma membrane that grows into cell 5.When reaches end of cell bacteria are released into apoplast and repeat the process on inner cells

Nodule formation 5.When reaches end of cell bacteria are released into apoplast and repeat the process on inner cells 6.Cortical cells near xylem form a nodule primordium

Nodule formation 5.When reaches end of cell bacteria are released into apoplast and repeat the process on inner cells 6.Cortical cells near xylem form a nodule primordium 7.When bacteria reach these cells the infection thread breaks off, forming vesicles with bacteria inside

Nodule formation 7.When bacteria reach these cells the infection thread breaks off, forming vesicles with bacteria inside 8.Vesicles fuse, form the peribacteroid membrane and bacteria differentiate into bacteroids.

Nodule formation 8.Vesicles fuse, form the peribacteroid membrane and bacteria differentiate into bacteroids. 9.Plant cells differentiate into nodules

Nodule formation 8.Vesicles fuse, form the peribacteroid membrane and bacteria differentiate into bacteroids. 9.Plant cells differentiate into nodules: have layer of cells to exclude O2 & vasculature to exchange nutrients

Nodule formation Plant cells differentiate into nodules: have layer of cells to exclude O2 & vasculature to exchange nutrients Complex process that is difficult to engineer: 21 non- legume plant genera have N-fixers

Nitrogen fixation N 2 + 8H + + 8e − + 16 ATP → 2NH 3 + H ADP + 16 Pi Catalysed by nitrogenase, a very complex enzyme!

Nitrogen fixation N 2 + 8H + + 8e − + 16 ATP → 2NH 3 + H ADP + 16 Pi Catalysed by nitrogenase, a very complex enzyme! Also catalyzes many other reactions Usually assayed by acetylene reduction

Nitrogen fixation N 2 + 8H + + 8e − + 16 ATP → 2NH 3 + H ADP + 16 Pi Usually assayed by acetylene reduction Sequentially adds 2 H per cycle until reach NH 3

Nitrogen fixation Sequentially adds 2 H per cycle until reach NH 3 May then be exported to cytosol & assimilated by GS/GOGAT or assimilated inside bacteroid

Nitrogen fixation Sequentially adds 2 H per cycle until reach NH 3 May then be exported to cytosol & assimilated by GS/GOGAT or assimilated inside bacteroid Are then converted to amides or ureides & exported to rest of plant in the xylem!

Nutrient uptake Most nutrients are dissolved in water

Nutrient uptake Most nutrients are dissolved in water Enter root through apoplast until hit endodermis

Nutrient uptake Most nutrients are dissolved in water Enter root through apoplast until hit endodermis Then must cross plasma membrane

Crossing membranes A) Diffusion through bilayer B) Difusion through protein pore C) Facilitated diffusion D) Active transport E) Bulk transport 1) Exocytosis 2) Endocytosis Selective Active

Nutrient uptake Then must cross plasma membrane Gases, small uncharged & non-polar molecules diffuse

Nutrient uptake Then must cross plasma membrane Gases, small uncharged & non-polar molecules diffuse down their ∆ [ ] Important for CO 2, auxin & NH 3 transport

Nutrient uptake Then must cross plasma membrane Gases, small uncharged & non-polar molecules diffuse down their ∆ [ ] Polar chems must go through proteins!

Selective Transport 1) Channels integral membrane proteins with pore that specific ions diffuse through

Selective Transport 1) Channels integral membrane proteins with pore that specific ions diffuse through depends on size & charge

Channels integral membrane proteins with pore that specific ions diffuse through depends on size & charge O in selectivity filter bind ion (replace H2O)

Channels integral membrane proteins with pore that specific ions diffuse through depends on size & charge O in selectivity filter bind ion (replace H2O) only right one fits

Channels O in selectivity filter bind ion (replace H2O) only right one fits driving force? electrochemical 

Channels driving force : electrochemical  “non-saturable”

Channels driving force : electrochemical  “non-saturable” regulate by opening & closing

Channels regulate by opening & closing ligand-gated channels open/close when bind specific chemicals

Channels ligand-gated channels open/close when bind specific chemicals Stress-activated channels open/close in response to mechanical stimulation

Channels Stress-activated channels open/close in response to mechanical stimulation voltage-gated channels open/close in response to changes in electrical potential

Channels Old model: S4 slides up/down Paddle model: S4 rotates

Channels Old model: S4 slides up/down Paddle model: S4 rotates 3 states 1.Closed 2.Open 3. Inactivated

Selective Transport 1) Channels 2) Facilitated Diffusion (carriers) Carrier binds molecule

Selective Transport Facilitated Diffusion (carriers) Carrier binds molecule carries it through membrane & releases it inside

Selective Transport Facilitated Diffusion (carriers) Carrier binds molecule carries it through membrane & releases it inside driving force = ∆ [ ]

Selective Transport Facilitated Diffusion (carriers) Carrier binds molecule carries it through membrane & releases it inside driving force = ∆ [ ] Important for sugar transport

Selective Transport Facilitated Diffusion (carriers) Characteristics 1) saturable 2) specific 3) passive: transports down ∆ []

Selective Transport 1) Channels 2) Facilitated Diffusion (carriers) Passive transport should equalize [ ] Nothing in a plant cell is at equilibrium!

Selective Transport Passive transport should equalize [ ] Nothing in a plant cell is at equilibrium! Solution: use energy to transport specific ions against their ∆ [ ]

Active Transport Integral membrane proteins use energy to transport specific ions against their ∆ [ ] allow cells to concentrate some chemicals, exclude others

Active Transport Characteristics 1) saturable molecules/s ions/s

Active Transport Characteristics 1) saturable 2) specific

Active Transport Characteristics 1) saturable 2) specific 3) active: transport up ∆ [ ] (or ∆ Em)

4 classes of Active transport ATPase proteins 1) P-type ATPases (P = “phosphorylation”) Na/K pump Ca pump in ER & PM H + pump in PM pumps H + out of cell

4 classes of Active transport ATPase proteins 1) P-type ATPases (P = “phosphorylation”) 2) V-type ATPases (V = “vacuole”) H + pump in vacuoles

4 classes of Active transport ATPase proteins 1) P-type ATPases (P = “phosphorylation”) 2) V-type ATPases (V=“vacuole”) 3) F-type ATPases (F = “factor”) a.k.a. ATP synthases mitochondrial ATP synthase chloroplast ATP synthase

4 classes of Active transport ATPase proteins 1) P-type ATPases (P = “phosphorylation”) 2) V-type ATPases (V = “vacuole”) 3) F-type ATPases (F = “factor”) 4) ABC ATPases (ABC = “ATP Binding Cassette”) multidrug resistance proteins

4 classes of Active transport ATPase proteins 1) P-type ATPases (P = “phosphorylation”) 2) V-type ATPases (V = “vacuole”) 3) F-type ATPases (F = “factor”) 4) ABC ATPases (ABC = “ATP Binding Cassette”) multidrug resistance proteins pump hydrophobic drugs out of cells very broad specificity

Secondary active transport Uses ∆ [ ] created by active transport to pump something else across a membrane against its ∆ [ ]

Secondary active transport Uses ∆ [ ] created by active transport to pump something else across a membrane against its ∆ [ ] Symport: both substances pumped same way

Secondary active transport Uses ∆ [ ] created by active transport to pump something else across a membrane against its ∆ [ ] Symport: both substances pumped same way Antiport: substances pumped opposite ways

Secondary active transport Uses ∆ [ ] created by active transport to pump something else across a membrane against its ∆ [ ] Symport: both substances pumped same way Antiport: substances pumped opposite ways

Nutrient uptake Gases enter/exit by diffusion down their ∆ [ ]

Nutrient uptake Gases enter/exit by diffusion down their ∆ [ ] Ions vary dramatically!

Nutrient uptake Gases enter/exit by diffusion down their ∆ [ ] Ions vary dramatically! H + is actively pumped out of cell by P-type H + -ATPase

Nutrient uptake Gases enter/exit by diffusion down their ∆ [ ] Ions vary dramatically! H + is actively pumped out of cell by P-type H + -ATPase and into vacuole by V-type!

Nutrient uptake H + is actively pumped out of cell by P-type H + -ATPase and into vacuole by V-type! Main way plants make membrane potential (∆Em)!

Nutrient uptake H + is actively pumped out of cell by P-type H + -ATPase and into vacuole by V-type! Main way plants make membrane potential (∆Em)! K + diffuses through channels down ∆Em

Nutrient uptake K + diffuses through channels down ∆Em Also taken up by transporters

Nutrient uptake K + diffuses through channels down ∆Em Also taken up by transporters some also transport Na +

Nutrient uptake K + diffuses through channels down ∆Em Also taken up by transporters some also transport Na + why Na + slows K + uptake?

Nutrient uptake K + diffuses through channels down ∆Em Also taken up by transporters some also transport Na + why Na + slows K + uptake? Na + is also expelled by H + antiport

Nutrient uptake K + diffuses through channels down ∆Em Also taken up by transporters some also transport Na + why Na + slows K + uptake? Na + is also expelled by H + antiport Enters through channels

Nutrient uptake Na + is also expelled by H + antiport Enters through channels Ca 2+ is expelled by P-type ATPases in PM

Nutrient uptake Na + is also expelled by H + antiport Enters through channels Ca 2+ is expelled by P-type ATPases in PM & pumped into vacuole by H + antiport

Nutrient uptake Na + is also expelled by H + antiport Enters through channels Ca 2+ is expelled by P-type ATPases in PM & pumped into vacuole by H + antiport enters cytosol via channels PO4, SO4, Cl & NO3 enter by H + symport

Nutrient uptake PO4, SO4, Cl & NO3 enter by H + symport also have anion channels of ABC type