Temperature sensing in plants

Question 1

importance of temperature sensing

Answer 1

need to react to stuff like season, time changes
adaptation to extreme events
important for crops in a changing climate

Question 2

what happens at high temps

Answer 2

first, thermomorphogenesis, an avoidance response where leaves get bigger and roots extend deeper etc
heat stress- hinders reproductive development and photosynthesis, reduced growth rate
severe heat stress- plant die :( cell die :( (unles plant been primed!)

Question 3

generalised effects of temperature on cells

Answer 3

impacts metabolism- e.g. enzyme activity, RNA stability
cytoskeleton integrity and membrane fluidity affected
ROS production

Question 4

role of phytochromes in temp sensing

Answer 4

temp can change the state of phytochromes (Pr/Pfr)

Question 5

what counteracts thermomorphogenesis

Answer 5

PhyB- can bind to PIFs and prevent them from initiating thermomorphogenesis

Question 6

evening complex

Answer 6

transcriptional repressor which helps time growth appropriately- less association at higher temps, so less PIF activity at higher temps

Question 7

RNA thermometer

Answer 7

name for RNA-folding based heat sensing- PIF7 for example forms a hairpin in the 5’UTR, and an alternative conformation emerging at high temperatures leads to increased translation

Question 8

what can help with heat shock

Answer 8

heat shock proteins no WAYYY
> e.g. HSFA1, many heat detection mechanisms converge on this, leads to activation of other heat shock proteins, ROS detoxification enzymes

unfolded protein response- unfolded proteins caused by heat are detected at the ER, countermeasures can be triggered- e.g. degrading misfolded products

Question 9

responses to low temp

Answer 9

vernalisation pathways (repression of flowering), suppression of growth/leaf expansion

worse:
ice crystals and mechanical wounding, drought stress-like conditions, eventual death

Question 10

membrane-based cold sensing

Answer 10

idea that cold means memvrane fluidity is lowered, not certain on the signal- calcium channels?

Question 11

what do cold response adaptation genes do

Answer 11

lipid and cell wall modification
hormone signalling
osmoprotectant production

Question 12

what are CBFs and how might they be triggered

Answer 12

TFs which are transcribed early in cold conditions and induce adaptive genes

tranacriptional cascade, or epigenetic factors leading to enhanced CBF binding

Question 13

how to CBFs work

Answer 13

directly reduce growth as well as induce other things- reduce GA levels