A new strategy to protect flowers from freezing stress
Liao Pan (廖攀), Chen Qin-Fang (陳琴芳),
Chye Mee-Len (蔡美蓮)
Wilson & Amelia Wong Professor in Plant Biotechnology
黃乾利辛烱僖基金教授席 (植物生物技術學)
School of Biological Sciences,
The University of Hong Kong
http://pcp.oxfordjournals.org/content/early/2014/02/19/pcp.pcu037
1
Significance: flowers develop into fruits and seeds (food)
Fruit crops
FOOD
Protected
Flowers
Freeze-damaged
Damaged flowers
LOSS
ACYL-COA-BINDING PROTEIN6
(ACBP6)
(醯基輔酶A結合蛋白6)
Arabidopsis
• A cold-inducible protein
• Expressed in both rosettes and
flowers
• Rosettes = vegetative tissues
• Flowers = reproductive tissues
Chen et al., 2008, Plant Physiol 148: 304-315
Rosettes
ACBP6 overexpression in transgenic Arabidopsis (轉基因擬南芥)
enhances freezing tolerance in rosettes
Chye et al (2013) US Patent No. 8,378,172
OE = overexpression lines;
3 OE lines were used to test reproducibility of results
Flowers
Freezing treatment on Arabidopsis flowers
1
4oC
3 days
2
-7oC 1 hour
3
Wild type
(WT)
ACBP6overexpressors
(OE)
Harvest
flower
samples
4
4oC 12 hours
ACBP6-overexpressing flowers are freeze-tolerant
Transformed Arabidopsis flower
overexpressing ACBP6 (ACBP6-OE)
shows intact petals (right)
while
the control succumbs to freezing stress (left).
(-7oC 1 hour)
54%
86%
flowers with intact petals
Liao et al. 2014, Plant & Cell Physiol
Why are ACBP6-OE flowers freezing tolerant?
After freezing treatment,
phosphatidylcholine (PC) (卵磷脂)
accumulates (25-34% > WT)
increasing membrane fluidity,
enhancing freezing tolerance.
PC increases membrane fluidity
Liao et al. 2014, Plant & Cell Physiol
Why are ACBP6-OE flowers freezing tolerant?
Plastid-specific membrane galactolipids (nmol mg-1)
質體特有的光合膜半乳糖脂（納摩爾每毫克）
MGDG
WT
OE-3
OE-5
29.6 ±
1.33
39.6 ±
0.53
36.0 ±
2.95
After freezing treatment,
Monogalactosyldiacylglycerol (MGDG) (單半乳糖二醯甘油酯)
accumulates [(MGDGOE-MGDGWT)/MGDGWT = 22-34% > WT]
enhancing freezing tolerance.
Liao et al., 2014, Plant & Cell Physiol
Conclusion
ACBP6 can be used to protect flowers (besides rosettes) from
freezing stress
Potential applications
Flower protection in
• agriculture (fruits, seeds)
• floriculture (cultivated blooms)
• cold region (citrus)
Research Output
http://pcp.oxfordjournals.org/content/early/2014/02/19/pcp.pcu037
P Liao, Q Chen, ML Chye (2014)
Transgenic Arabidopsis Flowers Overexpressing Acyl-CoA-Binding Protein
ACBP6 are Freezing Tolerant.
Plant & Cell Physiology doi:10.1093/pcp/pcu037
US Patent No. 8,378,172
Acknowledgements
Funded by
Wilson & Amelia Wong Endowment Fund (Plant Biotechnology)
The University of Hong Kong (CRCG 104001061)
Thank you for your attention