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.pcu0371

Significance: flowers develop into fruits and seeds (food)

Fruit crops Flowers Damaged flowersProtected Freeze-damaged

FOOD LOSS

ACYL-COA-BINDING PROTEIN6 (ACBP6)

( 醯基輔酶 A結合蛋白 6)

• 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

Arabidopsis

Chye et al (2013) US Patent No. 8,378,172

ACBP6 overexpression in transgenic Arabidopsis (轉基因擬南芥 )

enhances freezing tolerance in rosettes

Rosettes

OE = overexpression lines; 3 OE lines were used to test reproducibility of results

Freezing treatment on Arabidopsis flowers

Flowers

Wild type (WT)

ACBP6-overexpressors

(OE)

4oC 3 days1

-7oC 1 hour2

4oC 12 hours

3

4Harvest flower samples

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).

Liao et al. 2014, Plant & Cell Physiol

54% 86% flowers with intact petals

(-7oC 1 hour)

Why are ACBP6-OE flowers freezing tolerant?

PC increases membrane fluidity

After freezing treatment,

phosphatidylcholine (PC) (卵磷脂 )

accumulates (25-34% > WT)

increasing membrane fluidity,

enhancing freezing tolerance.

Liao et al. 2014, Plant & Cell Physiol

Liao et al., 2014, Plant & Cell Physiol

WT OE-3 OE-5

MGDG 29.6 ± 1.33 39.6 ± 0.53 36.0 ± 2.95

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）

Why are ACBP6-OE flowers freezing tolerant?

After freezing treatment,

Monogalactosyldiacylglycerol (MGDG) ( 單半乳糖二醯甘油酯 )

accumulates [(MGDGOE-MGDGWT)/MGDGWT = 22-34% > WT]

enhancing freezing tolerance.

ACBP6 can be used to protect flowers (besides rosettes) from freezing stress

Conclusion

Potential applications

Flower protection in

• agriculture (fruits, seeds)

• floriculture (cultivated blooms)

• cold region (citrus)

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

Research Output

Acknowledgements

Funded by

Wilson & Amelia Wong Endowment Fund (Plant Biotechnology)

The University of Hong Kong (CRCG 104001061)

Thank you for your attention