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Curriculum Vitae

YU Lab

YU Hao (Assistant Professor) Contact Information: Department of Biological Sciences Faculty of Science National University of Singapore 14 Science Drive 4 Singapore 117543 Tel: 65163048 Fax: 67792486 Email: dbsyuhao@nus.edu.sg

Research Areas:

Functional Genomics; Plant Growth Regulation; Plant Physiology

Research Interests:

The completion of the Arabidopsis genome sequence is a critical milestone of plant science. At current stage, a publicized goal is to clarify the function of all sequenced Arabidopsis genes. My interests are to investigate gene regulatory networks involved in the control of reproductive development and hormone signaling in Arabidopsis. Studies on Arabidopsis not only gain basic information on developmental mechanisms, but also provide useful clues in genetic engineering of economically important crops, such as orchids.

Current Projects:

1) Clarification of genetic networks during floral transition in Arabidopsis

Among the multitude of developmental phases in plants, the one which brings transition from vegetative to reproductive stage is the most exciting and complex one. We have found the important function of a putative transcription factor, AGL24, in the genetic crosstalk among the gene loci involved in the control of flowering time. The level of AGL24 mRNA expression is corresponding to the alteration of flowering time in that overexpression of AGL24 causes early flowering, while reduction of AGL24 expression causes late flowering. Now we are further studying the flowering genetic networks involving AGL24 and its close homologs, SVP and SOC1, to clarify the transcriptional hierarchy during floral transition.

2) Investigation of gene interactions in floral meristem development in Arabidopsis

Coupled with the floral transition, the development of floral meristem is one of the most attractive topics in molecular genetics, in which a lot of regulatory genes are interacting to promote flower development. We have identified that it is AGL24 that provides inflorescence identity to newly initiated floral meristems, and thus opposes flower development. If AGL24 is ectopically expressed in developing flowers, these flowers show inflorescence characteristics, and loss of function of AGL24 prevents the inflorescence phenotypes of mutations in the floral promoting genes LEAFY and APETALA1. We further proved that APETALA1 is a direct repressor of AGL24, SVP and SOC1, thus revealing a circuit of genetic interactions that is critical for flower development. We are now investigating the function of these flowering time genes in floral organ development.

3) Investigation of the involvement of GA signaling pathway in floral development

Gibberellin plays an important role in many aspects of plant growth and development, such as seed germination, stem elongation and floral development. It has been recently proposed that GA may regulate many developmental processes through five DELLA domain-containing GRAS regulatory proteins in the signaling pathway. We are now investigating how GA signaling genes are involved in the control of flowering time and floral organ development.

4) Clarification of genes function during floral transition in orchids

Orchids are the most popular cut flowers in the floral trade in the countries of Southeast Asia. In particular, Singapore is the second major countries in the world in terms of the export of orchid cut flowers. However, genetic breeding and culturing of orchids by conventional ways are not able to match the rapidly increased demand for orchid variety and production. We have created genetic transformation systems for several Dendrobium orchids via Agrobacterium tumefaciens or particle bombardment. In addition, we are identifying new selection agents and markers for orchid transformation. By using the established systems, we are investigating a series of developmental genes involved in orchid flower development. This study will contribute to the improvement of genetic manipulation of orchid genes to change floral traits in orchids.

Awards:

2007: Singapore Youth Award for Science and Technology
2007: NUS Young Researcher Award
2006: Singapore National Academy of Sciences and A*STAR Young Scientist Award
2005: Finalist for Singapore National Academy of Sciences and A*STAR Young Scientist Award
2002&2003: National University of Singapore Overseas Fellowship
2001: Gold medal of International Society of Plant Molecular Biology for outstanding NUS PhD thesis

Publications:

1. Hou X, Hu W-W, Shen L, Lee LYC, Tao Z, Han J-H, Yu H (2008) Global identification of DELLA target genes during Arabidopsis flower development. Plant Physiology 147: 1126-1142

2. Li D, Liu C, Shen L, Wu Y, Chen H, Robertson M, Helliwell CA, Ito T, Meyerowitz EM, Yu H (2008) A repressor complex governs the integration of flowering signals in Arabidopsis. Developmental Cell 15: 110-120.

3. Han P, Garcia-Ponce B, Fonseca-Salazar G, Alvarez-Buylla ER, Yu H (2008) AGAMOUS-LIKE 17, a novel flowering promoter, acts in a FT-independent photoperiod pathway. Plant Journal 55: 253-265

4. Lim TS, Chitra TR, Tay BH, Pua EC, Yu H (2008) Molecular characterization of Arabidopsis and Brassica juncea Cu/Zn-superoxide dismutases reveals their direct involvement in shoot regeneration. Journal of Plant Growth Regulation 27: 99-109

5. Liu C, Chen H, Er HL, Soo HM, Kumar P, Han J-H, Liou YC, Yu H (2008) Direct interaction of AGL24 and SOC1 integrates flowering signals in Arabidopsis. Development 135: 1481-1491.

6. Chai D, Yu H (2008) Bloom time for genetically engineered orchids. Innovation Magazine 8: 68-69.

7. Chai D, Yu H (2007) Recent advances in transgenic orchid production. Orchid Science and Biotechnology 1: 34-39.

8. Ito T, Ng KH, Lim TS, Yu H, Meyerowitz EM (2007) The Homeotic Protein AGAMOUS Controls Late Stamen Development by Regulating a Jasmonate Biosynthetic Gene in Arabidopsis. Plant Cell 19: 3516-3529.

9. Gan Y, Yu H, Peng J, Broun P (2007) Genetic and molecular regulation by DELLA proteins of trichome development in Arabidopsis thaliana. Plant Physiology 145: 1031-1042.

10. Chai D, Lee SM, Ng JH, Yu H (2007) L-methionine sulfoximine as a novel selection agent for genetic transformation of orchids. Journal of Biotechnology 131: 466–472.

11. Gan Y, Liu C, Yu H, Broun P (2007) Integration of cytokinin and gibberellin signalling by Arabidopsis transcription factors GIS, ZFP8 and GIS2 in the regulation of epidermal cell fate. Development 134: 2073-2081.

12. Liu C, Zhou J, Bracha-Drori K, Yalovsky S, Ito T, Yu H (2007) Specification of Arabidopsis floral meristem identity by repressing flowering time genes. Development 134: 1901-1910.

13. Yu H, Xu Y (2007) Orchids. In: Pua EC and Davey MR (eds.) Biotechnology in Agriculture and Forestry, Vol 61. Springer-Verlag, Berlin Heidelberg, Germany, pp 273-288.

14. Yu H (2007) Identification of floral organ identity genes in the orchid. Biomolecular Frontiers 2: e5. (News and Views)

15. Lim TS, Chitra TR, Han P, Pua EC, Yu H (2006) Cloning and molecular characterization of Arabidopsis and Brassica juncea flavin-containing amine oxidases. J.  Exp. Bot. 57: 4155-4169.

16. Gan Y, Kuminoto R, Liu C, Ratcliffe O, Yu H, Broun P (2006) GLABROUS INFLORESCENCE STEMS modulates gibberellin signaling in the regulation of epidermal differentiation and shoot maturation in Arabidospsis. Plant Cell 18: 1383-1395.

17. Xu Y, Teo LL, Zhou J, Kumar P, Yu H (2006) Floral organ identity genes in the Dendrobium orchids. Plant Journal 46: 54-68.

18. Yu H, Dhavale T, Yang S (2006) Molecular mechanisms of hormone functions in flowering. In Teixeira da Silva JA. (ed.) Floriculture, Ornamental and Plant Biotechnology: Advances and Topical Issues, Ed 1 Vol 1. Global Science Books, London, UK, pp 25-32.

19. Zhao Y, Medrano L, Ohashi K, Fletcher JC, Yu H, Sakai H, Meyerowitz EM (2004) HANABA TARANU is a GATA transcription factor that regulates shoot apical meristem and flower development in Arabidopsis. Plant Cell 16: 2586-2600.

20. Yu H, Ito T, Zhao Y, Peng J, Kumar P, Meyerowitz EM (2004) Floral homeotic genes are targets of gibberellin signaling in flower development. Proc. Natl. Acad. Sci. USA 101: 7827-7832.

21. Ito T, Wellmer F, Yu H, Das P, Ito N, Alves-Ferreira M, Riechmann JL, Meyerowitz EM (2004) The Arabidopsis organ identity protein AGAMOUS controls microsporogenesis through regulation of SPOROCYTELESS/NOZZLE. Nature 430: 356-360.

22. Yu H, Ito T, Wellmer F, Meyerowitz EM (2004) Repression of AGAMOUS-LIKE 24 is a crucial step in promoting flower development. Nature Genetics 36: 157-161.

23. Yang SH, Yu H, Xu Y, Goh CJ (2003) Investigation of cytokinin-deficient phenotypes in Arabidopsis by ectopic expression of orchid DSCKX1. FEBS Letters 555: 291-296.

24. Yu H, Kumar P (2003) Post-transcriptional gene silencing in plants by RNA. Plant Cell Rep. 22: 167-174.

25. Yang SH, Yu H, Goh CJ (2003) Functional characterisation of a cytokinin oxidase gene DSCKO1 in Dendrobium orchid. Plant Mol. Biol. 51: 237-248.

26. Yu H, Xu Y, Tan EL, Kumar P (2002) AGAMOUS-LIKE 24, a dosage-dependent mediator of the flowering signals. Proc. Natl. Acad. Sci. USA 99: 16336-16341.

27. Yang SH, Yu H, Goh CJ (2002) Isolation and characterization of the orchid cytokinin oxidase DSCKO1 promoter. J.  Exp. Bot. 53: 1899-1907.

28. Yu H, Yang SH, Goh CJ (2002) Spatial and temporal expression of the orchid floral homeotic gene DOMADS1 is mediated by its upstream regulatory elements. Plant Mol. Biol. 49: 225-237.

29. Yu H, Yang SH, Goh CJ (2001) Agrobacterium-mediated transformation of a Dendrobium orchid using the class 1 knox gene DOH1. Plant Cell Rep. 20: 301-305

30. Yu H, Goh CJ (2001) Molecular genetics of reproductive biology in orchids. Plant Physiol. 127: 1390-1393.

31. Yu H, Yang SH, Goh CJ (2000) DOH1, a class 1 knox gene, is required for maintenance of the basic plant architecture and floral transition in orchid. Plant Cell 12: 2143-2159

32. Yu H, Goh CJ (2000) Identification and characterization of three orchid MADS-box genes of the AP1/AGL9 subfamily during floral transition. Plant Physiol. 123: 1325-1336.

33. Yu H, Goh CJ (2000) Differential gene expression during floral transition in an orchid hybrid Dendrobium Madame Thong-In. Plant Cell Rep. 19: 926-931.