Abstract
Auxin transport at least correlates to the three gene families: efflux carriers PIN-formed (PIN), p-glycoprotein (PGP), and influx carrier auxin resistant 1/like aux1(AUX/LAX) in Arabidopsis thaliana. In monocotyledon Sorghum bicolor, the biological function of these genes retains unclear. Our previous study reported that the member analysis, organ-specific expression and expression profiles of the auxin transporter PIN, PGP and AUX/LAX gene families in Sorghum bicolor under IAA, brassinosteroid, polar auxin transport inhibitors and abiotic stresses. Here we further supply the prediction of subcellular localization of SbPIN, SbLAX and SbPGP proteins and discuss the potential relationship between the subcellular localization and stress response. The predicted results showed that the most of SbPIN, SbLAX and SbPGP proteins are localized to the plasma membrane, except few localized to vacuolar membrane and endoplasmic reticulum. This data set provides novel information for investigation of auxin transporters in Sorghum bicolor.
Keywords: AUX/LAX, PGP, PIN, Sorghum bicolor, subcellular localization
The intercellular auxin transport depends on the polar subcellular localization of PIN-formed (PIN) auxin efflux carriers at the plasma membrane (PM) and endoplasmic reticulum (ER).1-3 In Arabidopsis, PIN1–PIN4 and PIN7 localize to the PM when PIN5, 6 and 8 localize to the ER, which likely mediate the transport of auxin between the ER lumen and cytosol, and then regulate the cellular auxin homeostasis.2-6 The direction of auxin flow within tissues is mainly determined by the asymmetric subcellular localization of PIN in each transporting cell. Since, uncovering the mechanisms controlling the subcellular dynamics of auxin transport machinery is important for plant response to all developmental signals from embryogenesis to organogenesis, vascular tissue differentiation and tropisms.7 In the other hand, the report of auxin transporter related to abiostresses was gradually revealed recently. Auxin influx transport AUX1 is essential for the lateral root proliferation component of the salt stress-induced morphogenic response;8 the promoters of the SbPIN, SbLAX and SbPGP genes contain numerous DNA elements predicted to respond to abscissic acid, drought and high salt stresses.9 To make clear if the subcellular localization of SbPIN, SbLAX and SbPGP proteins also related to abiostresses response, here we first predicted their subcellular localization by http://wolfpsort.org/ (Table 1).10 SbPIN2, 5, 6, 7, 8 and 10 were showed the more motifs localized in PM when SbPIN1, 3, 4, 9 and 11 were showed the more motifs localized in vacuolar membrane (VM). The five SbLAXs all showed the most motifs in PM, even though there are fewer motifs in E.R or VM. The 24 SbPGPs members almost were localized in PM besides the both SbPGP5 and SbPGP11 also contained the more motifs localized in chloroplast. The above data were similar with the prediction of subcelluar localization of PIN in Arabidopsis (Table S1). Compare the prediction with the published data of subcelluar localization of six AtPINs, the prediction analysis of the AtPIN1, 3, 4 and 7 were consistent with the published data.2-6 Thus, these analyses suggested that the prediction of subcelluar localization of auxin carriers SbPIN, SbLAX and SbPGP was also useful for their experimental research. By previous report, the regulation of PIN protein polarity is needed to quickly respond and adapt plant development to internal and external stimuli.11 At the cellular level, various signals are translated into specific changes in the polar subcellular localization of PIN family thereby guiding the intercellular fluxes of auxin;11 dark treatment affects the subcellular localization of PIN1 and auxin maxima;12 various environmental and endogenous signals can modulate trafficking and polarity of PIN proteins and then change auxin distribution.13 Namely, the subcellular localization of PIN protein may relate to abiotic stresses responses. Future experiments of subcellular localization and abiotic stress responses need to be performed to confirm the bioinformatics prediction.
Table 1. Prediction of subcellular localization of auxin carriers PIN, AUX/LAX and PGP in Sorghum bicolor.
| Gene name a | Locus identifier b |
Accession number c |
plasma membrane | endoplasmic reticulum | vacuolar membrane | chloroplast |
|---|---|---|---|---|---|---|
|
AtPIN1 |
At01 g73590 |
Q9C6B8 |
7 |
2 |
2 |
1 |
|
AtPIN2 |
At05 g57090 |
Q9LU77 |
5 |
|
6 |
|
|
AtPIN3 |
At01 g70940 |
Q9S7Z8 |
7 |
|
|
3 |
|
AtPIN4 |
At02 g01420 |
Q8RWZ6 |
9 |
2 |
2 |
|
|
AtPIN5 |
At05 g16530 |
Q9FFD0 |
1 |
|
12 |
|
|
AtPIN6 |
At01 g77110 |
Q9SQH6 |
6 |
|
4 |
2 |
|
AtPIN7 |
At01 g23080 |
Q940Y5 |
8 |
2 |
|
2 |
|
AtPIN8 |
At05 g15100 |
Q9LFP6 |
5 |
3 |
2 |
3 |
|
SbPIN1 |
Sb02 g029210 |
C5X4P5 |
4 |
|
8 |
|
|
SbPIN2 |
Sb03 g029320 |
C5XF44 |
8 |
|
1 |
2 |
|
SbPIN3 |
Sb03 g032850 |
C5XIA5 |
1 |
|
10 |
|
|
SbPIN4 |
Sb03 g037350 |
C5XMI2 |
3 |
|
6 |
1.5 |
|
SbPIN5 |
Sb03 g043960 |
C5XG98 |
9 |
2 |
1 |
|
|
SbPIN6 |
Sb04 g028170 |
ND d |
11 |
|
|
1 |
|
SbPIN7 |
Sb05 g002150 |
C5Y431 |
8 |
2 |
|
3 |
|
SbPIN8 |
Sb07 g026370 |
C5YI36 |
5 |
|
5 |
1 |
|
SbPIN9 |
Sb10 g004430 |
C5Z4U5 |
5 |
|
9 |
|
|
SbPIN10 |
Sb10 g008290 |
C5Z7E9 |
6 |
2 |
2 |
1 |
|
SbPIN11 |
Sb10 g026300 |
C5Z7A0 |
6 |
|
8 |
|
|
SbLAX1 |
Sb01 g026240 |
C5WP27 |
11 |
2 |
|
|
|
SbLAX2 |
Sb01 g041270 |
C5WR01 |
11 |
3 |
|
|
|
SbLAX3 |
Sb03 g040320 |
C5XQG2 |
10 |
|
3 |
|
|
SbLAX4 |
Sb05 g004250 |
C5Y5L4 |
10 |
3 |
|
|
|
SbLAX5 |
Sb09 g021990 |
C5YYU5 |
9 |
3.5 |
|
|
|
SbPGP1 |
Sb01 g039110 |
C5WPA9 |
8 |
3 |
3 |
|
|
SbPGP2 |
Sb02 g019540 |
C5X8A6 |
13 |
|
|
|
|
SbPGP3 |
Sb03 g011860 |
C5XI10 |
10 |
|
1 |
|
|
SbPGP4 |
Sb03 g023740 |
C5XMA7 |
12 |
|
|
|
|
SbPGP5 |
Sb03 g031990 |
C5XHH9 |
5 |
2 |
|
6 |
|
SbPGP6 |
Sb03 g032000 |
C5XHI0 |
13 |
|
|
|
|
SbPGP7 |
Sb03 g032030 |
C5XHI4 |
11 |
2 |
|
|
|
SbPGP8 |
Sb03 g033290 |
C5XIE9 |
12 |
2 |
|
|
|
SbPGP9 |
Sb03 g047490 |
C5XJF5 |
8 |
2 |
1 |
1 |
|
SbPGP10 |
Sb04 g006087 |
C5XX25 |
12 |
|
1 |
|
|
SbPGP11 |
Sb04 g006090 |
C5XX26 |
5 |
|
2 |
6 |
|
SbPGP12 |
Sb04 g006100 |
C5XX27 |
3 |
2 |
|
3 |
|
SbPGP13 |
Sb04 g022480 |
C5XU71 |
5 |
2 |
|
4 |
|
SbPGP14 |
Sb04 g031170 |
C5Y0R2 |
11 |
1 |
|
|
|
SbPGP15 |
Sb06 g001440 |
C5YC52 |
9 |
2 |
|
|
|
SbPGP16 |
Sb06 g018860 |
C5Y9T7 |
12 |
2 |
|
|
|
SbPGP17 |
Sb06 g020350 |
C5YAT5 |
5 |
3 |
|
2 |
|
SbPGP18 |
Sb06 g030350 |
C5Y8Z4 |
11 |
|
|
1 |
|
SbPGP19 |
Sb07 g003510 |
C5YGW7 |
12 |
|
|
1 |
|
SbPGP20 |
Sb07 g003520 |
C5YGW8 |
13 |
|
|
|
|
SbPGP21 |
Sb07 g023730 |
C5YMS8 |
5 |
2 |
|
|
|
SbPGP22 |
Sb09 g002940 |
C5YZK3 |
11 |
|
|
|
|
SbPGP23 |
Sb09 g027320 |
C5YUY3 |
14 |
|
|
|
| SbPGP24 | Sb09 g027330 | C5YUY4 | 10 | 1 |
Acknowledgments
This research is supported by the National Natural Science Foundation of China (grant no. 31071392, 30971703 and 3117462), the Genetically Modified Organisms Breeding Major Projects (2009ZX08009–1238)and the Natural Science Foundation of Zhejiang province, China (grant no. Y3080111).
Footnotes
Previously published online: www.landesbioscience.com/journals/psb/article/17968
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