Module 5: Cell Signaling: 5 Signaling in Plants Flashcards
Plants coordinate their activities in response to changing conditions of: (3)
- light
- dark
- temperature
The plant’s cycle of growth, flowering, and fruiting involves signaling among (what parts of the plant): (3)
- roots
- stems
- leaves
Signaling in plants includes understanding how plant cells communicate with one another and respond to __.
light
evolved independently in plants and animals.
- Multicellularity
- cell communication
Plants and animals share the use of __, __, __, and __ for signaling.
- nitric oxide (NO)
- cyclic GMP
- Ca²⁺
- Rho family GTPases
The genome of __ does not encode homologs of the nuclear receptor family, Ras, JAK, STAT, TGFβ, Notch, Wnt, or Hedgehog signaling pathways.
Arabidopsis thaliana
The genome of Arabidopsis thaliana does not encode homologs of the __ (8) signaling pathways.
- nuclear receptor family
- Ras
- JAK
- STAT
- TGFβ
- Notch
- Wnt
- Hedgehog
Plants do not use __ for signaling.
cyclic AMP
- Cell-surface receptors in plants are __. (what type)
- They include transmembrane receptor __.
- These receptors have a __ and an __ . (what domains)
- enzyme-coupled
- serine/threonine kinases
- serine/threonine kinase cytoplasmic domain
- extracellular ligand-binding domain
a type of cell-surface receptor in plants.
Leucine-rich repeat (LRR) receptor kinases
There are __ (how many) LRR receptor kinases identified in Arabidopsis thaliana, including __, which is part of a cell-surface steroid hormone receptor.
- 175
- Bri1
regulate the growth and differentiation of plants
Brassinosteroids
The binding of __ to a Br1 cell-surface receptor kinase leads to the __ of specific transcription regulatory proteins.
- brassinosteroids
- degradation
- __, also known as __ or __, help to coordinate plant development.
- These are small molecules produced by most plant cells and can diffuse readily through cell walls.
- can act locally or be transported to influence cells located further away.
- Plant hormones
- phytohormones
- plant growth regulators
Major types of plant hormones include: (6)
- ethylene
- auxin
- cytokinin
- gibberellins
- abscisic acid
- brassinosteroids
- a small gas molecule that plays several roles in plant physiology.
- promotes fruit ripening, leaf abscission, and plant senescence and acts as a stress signal in response to wounding, infection, and flooding.
ethylene
Ethylene promotes __, __, and __.
- fruit ripening
- leaf abscission
- plant senescence
Ethylene acts as a stress signal in response to __, __, and __.
- wounding
- infection
- flooding
In plants, it is located in the endoplasmic reticulum and consists of dimeric, multipass transmembrane proteins.
Ethylene receptors
In plants, it has a copper-containing ethylene binding domain that interacts with cytoplasmic regions.
CTR1
Ethylene Signaling Pathway:
- __ stimulates the ubiquitylation and degradation of the nuclear transcription regulator __ in proteasomes.
- The binding of __ activates the receptors, altering their conformation, which prevents them from activating certain genes.
- Once released from degradation, __ can now activate the transcription of a large number of __.
- CTR1
- EIN3
- ethylene
- EIN3
- ethylene-responsive genes
It promotes growth toward light, upward growth rather than branching out, and downward root growth.
Auxin
Auxin is also known as
indole-3-acetic acid
Auxin promotes growth toward __, __ growth, and __ root growth.
- light
- upward
- downward
- It is involved in the initiation and positioning of various plant structures, aiding in flowering and fruiting.
- It influences gene expression by controlling the degradation of transcription regulators.
Auxin
stimulates the ubiquitylation and degradation of repressor proteins that block the transcription of auxin target genes in unstimulated cells.
Auxin
Auxin stimulates the ubiquitylation and degradation of repressor proteins that block the transcription of __ in unstimulated cells.
auxin target genes
Auxin has its transport system within plant cells.
The transport system includes plasma-membrane-bound __ and __. (what proteins)
- influx transporter proteins
- efflux transporter proteins
In the transport system of auxin, it can be distributed asymmetrically in the plasma membrane, affecting auxin distribution within the plant.
efflux transporters
- The localization of __ and the direction of __ are highly dynamic and regulated.
- This regulation is achieved by controlling the traffic of __.
- Auxin also inhibits __.
- auxin transporters
- auxin flow
- vesicles
- root-cell elongation
- Light-sensitive proteins are known as __.
- These proteins have a covalently attached light-absorbing __, which changes shape in response to light, inducing a change in the protein’s conformation.
- photoproteins
- chromophore
- involved in sensing red light (activates) and far-red light (inactivates).
- can phosphorylate themselves and then phosphorylate one or more proteins in the cell.
- They translocate into the nucleus and activate transcription regulators.
Phytochromes
Phytochromes are involved in sensing __ light (activates) and __ light (inactivates).
- can __ themselves and then __ one or more proteins in the cell.
- They translocate into the __ and activate __.
- red
- far-red
- phosphorylate
- phosphorylate
- nucleus
- transcription regulators
detected by __ and __.
- phototropin
- cryptochromes
responsible for phototropism, the tendency of plants to grow toward light.
Phototropin
flavoproteins that are sensitive to blue light.
Cryptochromes
- These proteins are involved in the repair of ultraviolet-induced DNA damage.
- also found in animals and play an important role in circadian clocks.
Cryptochromes
