Plant BIOCHEMISTRY LABORTORY

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Clive Lo

Associate Professor

School of Biological Sciences

The University of Hong Kong

7N-04 Kadoorie Biological Sciences Building

Pokfulam Road

Hong Kong

China

Email: clivelo@hku.hk; Tel: (852) 3917-3337

Dr. Clive's portrait

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EDUCATION

PhD (Botany and Plant Pathology), Purdue University, West Lafayette, Indiana, USA

BSc and MPhil (Biology), The Chinese University of Hong Kong, Shatin, Hong Kong

PREVIOUS POSITIONS

Assistant Professor, School of Biological Sciences and Department of Botany, The University of Hong Kong

Research Assistant Professor, Department of Botany, The University of Hong Kong

Research Scientist, Paradigm Genetics Inc., Research Triangle Park, North Carolina, USA

TEACHING

BIOL1110 From Molecules to Cells

BIOL1309 Evolutionary Diversity

BIOL2220 Principles of Biochemistry


RESEARCH HIGHLIGHTS

Our research laboratory is investigating plant specialized metabolites (such as flavonoids, stilbenes, and lignin) in cereal grasses including rice, sorghum, and sugarcane. Using rice as a model system, we have completed the elucidation of the metabolic pathway leading to the biosynthesis of tricin which is a prominent soluble flavonoid metabolite in grass biomass.  We have identified the key enzymes flavone synthase II and flavone 3',5'-hydroxylase which are highly conserved in the grass family (Poaceae).  Furthermore, we have demonstrated that the same metabolic pathway also produces tricin as a monomer for incorporation into cell wall lignin.  Tricin-lignin is a unique feature in the grass family.  Lignin is a complex phenolic biopolymer which provides mechanical strength and structural integrity in all vascular plants.  On the other hand, lignin is a barrier for utilization of cellulose as a feedstock for biofuel ethanol production.  Our work indicates that disruption of tricin biosynthesis at specific steps could increase cellulose digestibility in rice biomass by lowering lignin content and changing lignin composition, without affecting growth and development.  Hence it represents a viable strategy for bioengineering of lignocellulosic grass biomass as feedstock for bioethanol production.

Meanwhile, we have been working on stilbene production in sorghum and wild sugarcane which are closely-related species belong to the Saccharinae subtribe.  Unlike flavonoids, stilbenes are sporadically present in the plant kingdom.  They are usually synthesized in response to abiotic and biotic stresses in specific plant species.  Our laboratory isolated a pathogen-inducible sorghum stilbene synthase gene (SbSTS1) which was the first STS gene reported in monocot.  Recently, we revealed the production of different O-methylated stilbenes in sorghum and wild sugarcane.  Using CRISPR-Cas9 mutagenesis and sorghum transformation technology, we demonstrated that a stilbene O-methylase (SbSOMT) is responsible for pterostilbene production in sorghum.  Pterostilbene is a potent antifungal compound involved in pathogen defense.  Besides their natural roles in plants, stilbenes are promising nutraceuticals with a range of health-beneficial properties.  Using a combination of biochemical, enzymatic, and structural analyses, we revealed the specific substrate binding mode that leads to O-methylation of the stilbene A-ring to produce pterostilbene.  Our discovery provides insights into bioengineering of specific O-methylated stilbenes for molecular breeding of crops or production of novel nutraceuticals. 

Currently, we are investigating the functions and regulation of flavonoid and stilbene biosynthesis in rice and sorghum.  Please feel free to contact us for potential research opportunities (postgraduate students, FYPs, Interns, etc.)

 


RECENT REPRESENTATIVE PUBLICATIONS

Lam LPY, Lui ACW, Bartley LE, Mikami B, Umezawa T*, Lo C* (2024) Multifunctional 5-hydroxyconiferaldehyde O-methyltransferases (CAldOMTs) in plant metabolism.  Journal of Experimental Botany DOI: 10.1093/jxb/erae011

Lui ACW, Pow KC, Lin N, Lam LPY, Liu Q, Godwin ID, Fan Z, Khoo CJ, Tobimatsu Y, Wang L, Hao Q*, Lo C* (2023) Regioselective stilbene O-methylations in Saccharinae grasses.  Nature Communications 14:3462.

Lam LPY, Wang L, Lui ACW, Liu H, Umezawa T, Tobimatsu Y, Lo C* (2023) Flavonoids in major cereal grains: distribution, functions, biosynthesis, and applications.  Phytochemistry Reviews.   22:1399-1438. 

Lam PY, Wang L, Lui ACW, Liu H, Takeda-Kimura Y, Chen MX, Zhu FY, Zhang J, Umezawa T, Tobimatsu Y, Lo C* (2022)   Deficiency in flavonoid biosynthesis genes CHS, CHI, and CHIL alters rice flavonoid and lignin profiles. Plant Physiology 28:1993-2011.

Lam PY, Lui ACW, Wang L, Liu H, Umezawa T, Tobimatsu Y, Lo C* (2021) Tricin biosynthesis and bioengineering.  Frontiers in Plant Sciences 12:733198.

Wang L, Lui, ACW, Lam PY, Liu, G, Godwin I, Lo C* (2020) Transgenic expression of flavanone 3-hydroxylase redirects flavonoid biosynthesis and alleviates anthracnose susceptibility in sorghum. Plant Biotechnology Journal 18:2170-2172.

Lui ACW, Lam PY, Chan KH, Wang L, Tobimatsu Y, Lo C* (2020) Convergent recruitment of 5'-hydroxylase activities by CYP75B flavonoid B-ring hydroxylases for tricin biosynthesis in Medicago legumes.  New Phytologist 228:269-284.  

Wang L, Lam PY, Lui ACW, Zhu FY, Chen MX, Liu H, Zhang J, Lo C* (2020) Flavonoids are indispensable for complete male fertility in rice.  Journal of Experimental Botany 71:4715-4728.

Lam PY, Lui ACW, Yamamura M, Wang L, Takeda Y, Suzuki S, Liu H, Zhu FY, Chen MX, Zhang J, Umezawa T, Tobimatsu Y, Lo C* (2019) Recruitment of specific flavonoid B-ring hydroxylases for two independent biosynthesis pathways of flavone-derived metabolites in grasses. New Phytologist 223:204-219.

Lam PY, Tobimatsu Y, Takeda Y, Suzuki S, Yamamura M, Umezawa T, Lo C* (2017) Disrupting  flavone synthase II alters lignin and improves biomass digestibility. Plant Physiology 174:972-985.

Lam PY, Liu H, Lo C* (2015) Completion of tricin biosynthesis pathway in rice: Cytochrome P450 75B4 is a novel chrysoeriol 5'-hydroxylase.  Plant Physiology 168:1527-1536.

Lam PY, Zhu FY, Chan WL, Liu H, Lo C* (2014) Cytochrome P40 93G1 is a flavone synthase II which channels flavanones to the biosynthesis of tricin O-linked conjugates in rice.  Plant Physiology 165:1315-1327.



COMPLETE PUBLICATION LIST