Rapid hyperosmotic-induced Ca 2+ responses in Arabidposis thaliana exhibit sensory potentiation and implicate roles for plastidial KEA transporters

Question 1

Sensory potentiation

Answer 1

rapid & reversible Ca2+ responses to subsequent hyperosmotic stress

Question 2

Slow Vacuolar (SV) 
channel TPC1

Answer 2

mediate a Ca2+-induced Ca2+release mechanism; required for root-to-shoot propagation of Ca2+

Question 3

reduced hyperosmolality-induced [Ca2+]i increase 1 (OSCA1)

Answer 3

OSCA1 can form plasma membrane-localized Ca2+channels; mutants have impaired perception of hyperosmotic stress; DUF221-containing proteins

Question 4

CSC1

Answer 4

osmotically-sensitive Ca2+-permeable channel

Question 5

apoplast

Answer 5

(plants) free diffusional space outside the plasma membrane

Question 6

plastid stroma

Answer 6

analogous to cytoplasm; requires low resting Ca2+ levels due to the presence of phosphates; Ca2+ is partitioned within the thylakoid lumen

Question 7

plastidial KEA transporters

Answer 7

plastid-localized K+/H+ antiporters necessary for eliciting wildtype levels of rapid hyperosmotic-induced Ca2+; mutants were still largely capable of exhibiting sensory potentiation

Question 8

Wild-Type Col-0

Answer 8

Wild-type Arabidopsis seedlings of the ecotype Col-0 expressing aequorin under control of the strong and constitutive 35S promote

Question 9

aequorin

Answer 9

bioluminescent Ca2+reporter protein

Question 10

abscisic acid (ABA)

Answer 10

modulates ion channel activity and transcriptional reprogramming; biosynthesis is induced by osmotic stress

Question 11

two-way analysis of variance (ANOVA)

Answer 11

examines the influence of two different categorical independent variables on one continuous dependent variable; aims at assessing the main effect of each independent variable AND also if there is any interaction between them

Question 12

hexasulfanyl-ABA (HS-ABA)

Answer 12

analogue of ABA; binds the PYR/PYL family of ABA receptors and disrupt the receptor interactions with inhibitory PP2C proteins, thereby leading to constitutive repression of ABA signaling

Question 13

MCA1/2 & MSL4/5/6/9/10

Answer 13

higher-order mechanosensitive Ca2+ channels

Question 14

KEA1 and KEA2

Answer 14

localized at the innerplastid envelope membrane; Loss of function results in morphologically swollen plastids and decreased photosynthetic activity

Question 15

KEA3

Answer 15

localized at the thylakoid membrane; mutants show morphologically intact chloroplasts, but mutation results in altered photosynthetic energy absorption under dynamic light conditions

Question 16

Potentiated

Answer 16

Up-regulated

Question 17

“priming” or “memory”

Answer 17

enhancement of responses after experiencing stress

Question 18

sensory adaptation

Answer 18

return to Ca2+ baseline; suggests that negative feedback mechanisms must exist to inactivate the sensory machinery, including closing Ca2+ channels and removal of cytosolic Ca2+ by active transport; ensures that the system remains responsive to further relative changes in stimulus intensity

Question 19

transfer DNA (T-DNA)

Answer 19

the transferred DNA of the tumor-inducing (Ti) plasmid of some species of bacteria such as Agrobacterium tumefaciens; transferred from bacterium into the host plant’s nuclear DNA genome; the T-DNA is bordered by 25-base-pair repeats on each end; initiated at the right border and terminated at the left border and requires the vir genes of the Ti plasmid