Stress responses/stress avoidance Plan C We will pick a problem in plant biology and see where it takes us. Plant products Climate/CO2 change Stress responses/stress avoidance

Stresses Chosen Climate change Temperature Increased pCO2 Drought pH Nutrient deprivation Metal toxicity (a result of low pH) Predation Shaking

Friday Present a plant stressor, what is known about it, and why it might affect plant 2˚ compounds in an ~ 10 minute presentation. Alternative: present another good plant/stressor response to study and why we should choose it over the ones already chosen.

John Austin: Jared Nicholoff: Maria Chinikaylo: David Pupaza: Fungal attack Cassia Cole: Kyle Schimmel: Christina Gambino: Drought Nathan Seabridge: Andrew Hasuga: Kenneth Werkheiser: Kelvin Mejia: Matt Yatison: UV radiation Alexis Morgan: Michael Yucha: Catherin Morocho: Atrazine? Cold? Shaking?Nutrient deprivation? Bact? Ozone? Smog? Heavy metals? Predation?Heat? Tom Nawrocki:

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

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

Natural Products 1˚ metabolites are essential for growth & development therefore present in all plants 2˚ metabolites “not” required for growth & development therefore not present in all plants Often only found in one or a few spp. Derived from 1˚ metabs

Natural Products 2˚ metabolites not present in all plants Often only found in one or a few spp. Derived from 1˚ metabs, can be hard to draw line Can be up to 3% of dry weight: very expensive to the the plant!

Natural Products >100,000 types; tremendous variety of functions Defense Attractant Protecting from UV metal uptake and transport Hardening cell walls

Natural Products >100,000 types; 3 main groups Terpenoids Alkaloids Phenolics

Natural Products >100,000 types; 3 main groups >30,000 terpenoids: made from isoprene units

Natural Products >100,000 types; 3 main groups >30,000 terpenoids: made from isoprene units Some with N, most w/o Monoterpenoids mostly essential oils

Natural Products >100,000 types; 3 main groups >30,000 terpenoids: made from isoprene units Some with N, most w/o Monoterpenoids mostly essential oils Longer ones have diverse functions Pigments Signals Defense

Natural Products >100,000 types; 3 main groups >30,000 terpenoids: made from isoprene units Longer ones have diverse functions Pigments Signals Defense Phytoecdysterones mimic ecdysone & cause molting

Natural Products >100,000 types; 3 main groups >30,000 terpenoids: made from isoprene units >12,000 Alkaloids: derived from amino acids: contain N

Natural Products >100,000 types; 3 main groups >30,000 terpenoids: made from isoprene units >12,000 Alkaloids: derived from amino acids: contain N Many drugs!

Natural Products >100,000 types; 3 main groups >30,000 terpenoids: made from isoprene units >12,000 Alkaloids: derived from amino acids: contain N Many drugs! Mainly for defense.

Natural Products >100,000 types; 3 main groups >30,000 terpenoids: made from isoprene units >12,000 Alkaloids: derived from amino acids: contain N >8,000 phenolics: contain phenol ring

Natural Products >100,000 types; 3 main groups >30,000 terpenoids: made from isoprene units >12,000 Alkaloids: derived from amino acids: contain N >8,000 phenolics: contain phenol ring Crucial for moving onto land! Strengthen cell wall enough to support wt on land & transport water

Phenolics >8,000 phenolics: contain phenol ring Crucial for moving onto land! Strengthen cell wall enough to support wt on land & transport water Comprise ~40% of organic C in the biosphere (most in cell walls)

Phenolics >8,000 phenolics: contain phenol ring Crucial for moving onto land! Strengthen cell wall enough to support wt on land & transport water Comprise ~40% of organic C in the biosphere (most in cell walls) Many serve other functions: Pigments

Phenolics >8,000 phenolics: contain phenol ring Crucial for moving onto land! Strengthen cell wall enough to support wt on land & transport water Comprise ~40% of organic C in the biosphere (most in cell walls) Many serve other functions: Pigments Signals

Phenolics >8,000 phenolics: contain phenol ring Crucial for moving onto land! Strengthen cell wall enough to support wt on land & transport water Comprise ~40% of organic C in the biosphere (most in cell walls) Many serve other functions: Pigments Signals Defense

Phenolics >8,000 phenolics: contain phenol ring Most are derived from phenypropanoid

Other natural products ~ 100 cyanogenic glycosides Release cyanide when plant is damaged Found in seeds of apricots, cherries, other fruits Laetrile

Other natural products > 100 glucosinolates: contain S and N

Other natural products > 100 glucosinolates: contain S and N Mainly found in Brassicaceae (crucifers)

Other natural products > 100 glucosinolates: contain S and N Mainly found in Brassicaceae (crucifers) Made from modified amino acids bonded to glucose

Other natural products > 100 glucosinolates: contain S and N Mainly found in Brassicaceae (crucifers) Made from modified amino acids bonded to glucose Function in defense

Other natural products > 100 glucosinolates: function in defense When damaged release Isothiocyanates nitriles and elemental sulfur Thiocyanates oxazolidine-thiones epithionitriles

Other natural products The genus Allium produces sulfoxides derived from cysteine

Other natural products The genus Allium produces sulfoxides derived from cysteine When plants are damaged they are converted to pungent volatiles

Seeds Seeds are unique feature of plants

Seeds Seeds are unique feature of plants Plant dispersal units

Seeds Seeds are unique feature of plants Plant dispersal units Must survive unfavorable conditions until they reach suitable place (and time) to start next generation

Seeds Seeds are unique feature of plants Plant dispersal units Must survive unfavorable conditions until they reach suitable place (and time) to start next generation Are dormant

Seeds Seeds are unique feature of plants Plant dispersal units Must survive unfavorable conditions until they reach suitable place (and time) to start next generation Are dormant; dehydration is key

Seeds Seeds are unique feature of plants Plant dispersal units Must survive unfavorable conditions until they reach suitable place (and time) to start next generation Are dormant; dehydration is key Germinate when conditions are right

Seeds Germinate when conditions are right Need way to sense conditions while dormant

Seeds Germinate when conditions are right Need way to sense conditions while dormant Need reserves to nourish seedling until it is established

Seeds (Usually) required for fruit development!

Seeds (Usually) required for fruit development! Role of fruit is to aid seed dispersal!

Seed Development (Usually) required for fruit development! Role of fruit is to aid seed dispersal! Unfertilized flowers don’t develop fruit

Seed Development (Usually) required for fruit development! Role of fruit is to aid seed dispersal! Unfertilized flowers don’t develop fruits The growth regulators GA, auxin or cytokinin can all induce parthenocarpy

Seed Development (Usually) required for fruit development! Role of fruit is to aid seed dispersal! Unfertilized flowers don’t develop fruits The growth regulators GA, auxin or cytokinin can all induce parthenocarpy GA + auxin or GA + cytokinin work best

Seed Development (Usually) required for fruit development! Role of fruit is to aid seed dispersal! Unfertilized flowers don’t develop fruits The growth regulators GA, auxin or cytokinin can all induce parthenocarpy GA + auxin or GA + cytokinin work best Hormones from embryo stimulate fruit development

Seed Development Hormones from embryo stimulate fruit development Other floral organs make inhibitor that blocks fruit development until they abscise

Seed Development Hormones from embryo stimulate fruit development Other floral organs make inhibitor that blocks fruit development until they abscise Divide seed development into three phases of ± equal time

Seed Development Divide seed development into three phases of ± equal time Morphogenesis

Seed Development Divide seed development into three phases of ± equal time Morphogenesis Maturation

Seed Development Divide seed development into three phases of ± equal time Morphogenesis Maturation Dehydration and dormancy

Seed Development End result is seed with embryo packaged inside protective coat

Seed Development End result is seed with embryo packaged inside protective coat Seed coat is maternal tissue!

Seed Development End result is seed with embryo packaged inside protective coat Seed coat is maternal tissue! Derived from epidermal tissue surrounding ovule

Seed Development Seed coat is maternal tissue! Derived from epidermal tissue surrounding ovule Determines shape of the seed!

Seed Development Seed coat is maternal tissue! Derived from epidermal tissue surrounding ovule Determines shape of the seed! Testa mutants have odd-shaped seeds

Seed Development Seed coat is maternal tissue! Derived from epidermal tissue surrounding ovule Determines shape of the seed! Testa mutants have odd-shaped seeds embryo grows to fill shape set by testa!

Seed Development End result is seed with embryo packaged inside protective coat Endosperm feeds developing embryo (3n grows faster)

Seed Development End result is seed with embryo packaged inside protective coat Endosperm feeds developing embryo (3n grows faster) In many dicots endosperm is absorbed as seed develops

Seed Development End result is seed with embryo packaged inside protective coat Endosperm feeds developing embryo (3n grows faster) In many dicots endosperm is absorbed as seed develops Often leave a thin layer of endosperm just inside testa

Seed Development End result is seed with embryo packaged inside protective coat Endosperm feeds developing embryo (3n grows faster) In many dicots endosperm is absorbed as seed develops Often leave a thin layer of endosperm just inside testa Seeds have three different genetic compositions!

Seed Development End result is seed with embryo packaged inside protective coat Endosperm feeds developing embryo (3n grows faster) In many dicots endosperm is absorbed as seed develops In many monocots endosperm is seedling food

Seed Development Embryogenesis Maturation: cell division ± ceases, but cells still expand

Seed Development Embryogenesis Maturation: cell division ± ceases, but cells still expand Controlled by different genes: viviparous mutants have normal morphogenesis but don’t mature

Seed Development Embryogenesis Maturation: cell division ± ceases, but cells still expand Controlled by different genes: viviparous mutants have normal morphogenesis but don’t mature Many morphogenesis mutants show normal maturation

Seed Development Maturation: cell division ± ceases, but cells still expand Activate new genes for making storage compounds

Seed Development Maturation: cell division ± ceases, but cells still expand Activate new genes for making storage compounds ABA made by maternal tissue initiates this process

Seed Development Maturation: cell division ± ceases, but cells still expand Activate new genes for making storage compounds ABA made by maternal tissue initiates this process Seed [ABA] increases as enter maturation phase

Seed Development Maturation: cell division ± ceases, but cells still expand Activate new genes for making storage compounds ABA made by maternal tissue initiates this process Seed [ABA] increases as enter maturation phase Switch to ABA synthesis by embryo & endosperm during maturation

Seed Development Maturation: cell division ± ceases, but cells still expand Activate new genes for making storage compounds Storage compounds are key for seedlings and crops

Seed Development Maturation: cell division ± ceases, but cells still expand Activate new genes for making storage compounds Storage compounds are key for seedlings and crops Proteins, lipids & carbohydrates but vary widely

Seed Development Maturation: cell division ± ceases, but cells still expand Activate new genes for making storage compounds Storage compounds are key for seedlings and crops Proteins, lipids & carbohydrates but vary widely Many 2˚ metabolites

Seed Development Maturation: cell division ± ceases, but cells still expand Activate new genes for making storage compounds Storage compounds are key for seedlings and crops Proteins, lipids & carbohydrates but vary widely Next prepare for desiccation as ABA made by embryo (+endosperm) increases

Seed Development Next prepare for desiccation as ABA made by embryo (+endosperm) increases ABA peaks at mid-maturation, then declines (but not to 0)

Seed Development Next prepare for desiccation as ABA made by embryo (+endosperm) increases ABA peaks at mid-maturation, then declines (but not to 0) Blocks vivipary during maturation

Seed Development Next prepare for desiccation as ABA made by embryo (+endosperm) increases Make proteins & other molecules (eg trehalose) that help tolerate desiccation

Seed Development Next prepare for desiccation as ABA made by embryo (+endosperm) increases Make proteins & other molecules (eg trehalose) that help tolerate desiccation Next dehydrate (to 5% moisture content) and go dormant

Seed Development Next dehydrate (to 5% moisture content) and go dormant Very complex: 2 classes of dormancy Coat-imposed embryo dormancy

Seed Development Coat-imposed dormancy (maternal effect) Preventing water uptake.

Seed Development Coat-imposed dormancy (maternal effect) Preventing water uptake. Mechanical constraint

Seed Development Coat-imposed dormancy (maternal effect) Preventing water uptake. Mechanical constraint Interference with gas exchange.

Seed Development Coat-imposed dormancy (maternal effect) Preventing water uptake. Mechanical constraint Interference with gas exchange Retaining inhibitors (ABA)

Seed Development Coat-imposed dormancy (maternal effect) Preventing water uptake. Mechanical constraint Interference with gas exchange Retaining inhibitors (ABA) Inhibitor production (ABA)

Seed Development Coat-imposed dormancy (maternal effect) Preventing water uptake. Mechanical constraint Interference with gas exchange Retaining inhibitors (ABA) Inhibitor production (ABA) Embryo dormancy (Zygotic effect)

Seed Development Coat-imposed dormancy (maternal effect) Embryo dormancy (Zygotic effect) Making inhibitors (ABA?)

Seed Development Coat-imposed dormancy (maternal effect) Embryo dormancy (Zygotic effect) Making inhibitors (ABA?) Absence of activators (GA)

Seed Development Coordinated with fruit ripening: fruit’s job is to protect & disperse seed Seeds remain dormant until sense appropriate conditions: some Lotus germinated after 2000 years!

Seed germination Seeds remain dormant until sense appropriate conditions: some Lotus germinated after 2000 years! Water

Seed germination Seeds remain dormant until sense appropriate conditions: some Lotus germinated after 2000 years! Water Temperature: some seeds require vernalization = prolonged cold spell

Seed germination Seeds remain dormant until sense appropriate conditions: some Lotus germinated after 2000 years! Water Temperature: some seeds require vernalization = prolonged cold spell May break down hydrophobic seed coat

Seed germination Seeds remain dormant until sense appropriate conditions: Water Temperature: some seeds require vernalization = prolonged cold spell May break down hydrophobic seed coat May allow inhibitor (eg ABA) to go away

Seed germination Seeds remain dormant until sense appropriate conditions: Water Temperature: some seeds require vernalization = prolonged cold spell May break down hydrophobic seed coat May allow inhibitor (eg ABA) to go away May allow synthesis of specific RNAs

Seed germination Seeds remain dormant until sense appropriate conditions: Water Temperature: some seeds require vernalization = prolonged cold spell May break down hydrophobic seed coat May allow inhibitor (eg ABA) to go away May allow synthesis of specific RNAs Many require light: says photosynthesis is possible

Seed germination Seeds remain dormant until sense appropriate conditions: Water Temperature: some seeds require vernalization = prolonged cold spell Many require light: says photosynthesis is possible often small seeds with few reserves