mRNA
Transcription
FP gene
(i) Transcriptional biosensors
DR5:reporter system
(ii) Translational biosensors
uNIP5;1 system
(iii) Degron-based biosensors
DII-VENUS, Jas9-Venus
(iv) Direct intrinsic/extrinsic biosensors
Yellow cameleon, GCaMP,
FLIP, ABACUS, GPS1
TF
Analyte
Fig. 1 Types of genetically encoded fluorescent biosensors. Fluorescent biosensors can be roughly distinguished into four groups: (i) transcriptional biosensors, monitoring analytes through transcriptional activity;
(ii) translational biosensors, monitoring analytes through mRNA stability/translational activity; (iii) degronbased biosensors, monitoring analytes through stability of FP; and (iv) direct intrinsic/extrinsic biosensors,
monitoring analytes through change of protein conformation (extrinsic biosensors) or protonation states of FPs
(intrinsic biosensors)
Table 1
Genetically encoded fluorescent biosensors used in plants
Target/analyte
Biosensor
Sensor type
Ref.
H
+ (pH)
pHluorin
Single FP intrinsic
[34]
Ratiometric pHluorin
[35]
PEpHluorin
[33]
PRpHluorin
[33]
GFP(H148D)
[36]
pHusion
Dual FP intrinsic
[37]
ATP
ATeam1.03-nD/nA
FRET-based sensor
[26, 27]
ROS
HyPer
Single FP extrinsic
[52–55]
Redox
roGFP2
Single FP intrinsic
[39–41]
L-Glu
iGluSnFR
Single FP extrinsic
[47]
Sucrose
FLIPsuc
FRET-based sensor
[19]
Glucose
FLIPglu
FRET-based sensor
[20]
Auxin
DR5:Reporter
Transcriptional sensor
[4]
DII-VENUS
Degron-based sensor
[5]
(continued)
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Akira Yoshinari et al.