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 Our group is interested in plant secondary metabolism and cotton biology. Current research includes investigation of terpene biosynthesis in Artemisia annua and cotton; plant secondary metabolites and plant-insect interactions; small RNAs and plant-mediated insect RNA interference; cotton fiber development. We are also interested in genetic engineering of cotton fiber development, plant resistance to insects, and production of artemisinin in A. annua.
Lab Homepage: http://sippe.ac.cn/xy。
Principal Investigator: Dr. Xiao-Ya Chen, Professor, Academician. Email: xychen@sibs.ac.cn
Staff: Ling-Jian Wang, Research Associate; Dr. Ying-Bo Mao, Research Assistant; Zhi-Ping Lin, Technician
Postdoctoral Fellows: Dr. Qi-Xia Ma; Dr. Yu-Kun Wei; Dr. Ya-Li Zhang
Graduate Students: Nan Yu; Chang-Qing Yang; Bing Xu; Gao-Jie Hong; Jian-Xu Li; Wen-Juan Cai; Xue-Yi Xue; Xiao-Yuan Tao; Chun-Min Shan; Zhong-Xia Yu; Xiang Gao; Lu-Men Chao; Ju-Xin Ruan
Graduated Students: Bin Luo, 2003 (PhD); Xue-Ying Guan, 2002 (PhD); Xiao-Xia Shangguan, 2003 (PhD)
Research of Cotton Fiber Development and Gossypol Biosynthesis
Cotton provides the most important natural fiber for textile industry. Cotton fibers elongate rapidly after initiation and deposit a large amount of cellulose after elongation. We compared transcriptomes and metabolite profiles of the two stages. We constructed a cotton fiber cDNA library and generated ~8,000 ESTs for an upland cotton cultivar, Gossypium hirsutum L. Xuzhou-142. Analysis with cDNA array identified 633 genes that were differentially regulated. The auxin signal, wall-loosening and lipid metabolism are highly active during fiber elongation, whereas the cellulose biosynthesis is predominant and many other metabolic pathways are down-regulated in the secondary cell wall synthesis stage. Transcript and metabolite profiles and enzyme activities are consistent in demonstrating a specialization process of cotton fiber development toward cellulose synthesis.
GhRDL1 is one of the genes that are highly expressed in developing fiber cells, its promoter contains a homeodomain binding L1 box and a MYB binding motif, both conferring trichome-specific expression in Arabidopsis. GaMYB2, a GL1-like gene of cotton, is expressed early in developing fiber cells. This cotton MYB protein was able to activate GhRDL1 promoter, transgenic data suggest its participation in regulating cotton fiber development. Promoter of GaMYB2 is trichome-specific in Arabidopsis and glandular trichome head-specific in tobacco. Cotton bHLH proteins homologous to GL3 may be involved in regulating GaMYB2 gene expression during cotton fiber development. Three homeobox (HOX) genes, GhHOX1, GhHOX2 and GhHOX3, were identified from ESTs and they may function differently in cotton fiber development.
We are also interested in gossypol biosynthesis, and have isolated genes encoding farnesyl diphosphate synthase (FDS), (+)-δ-cadinene synthase (CAD1), (+)-δ-cadinene-8-hydroxylase (CYP706B1), two cotton cytochrome P450 reductases and a WRKY transcription factor of the gossypol pathway. CYP706B1 is encoded by a single copy gene in the cotton genome, and it might be a good target for down-regulating gossypol biosynthesis in cottonseeds through genetic engineering. Plant secondary metabolism plays an important role in plant defense reactions. Starting from analysis of cotton bollworm tolerance to gossypol, a new RNAi technology against insects via plant-mediated insect RNAi was developed.
Major Publications:
Shangguan XX, Xu B, Yu ZX, Wang LJ, Chen XY. (2008) Promoter of a cotton fibre MYB gene functional in trichomes of Arabidopsis and glandular trichomes of tobacco. Journal of Experimental Botany 59: 3533-3542. Guan XY, Li QJ, Shan CM, Wang S, Mao YB, Wang LJ, Chen XY. (2008) The HD-Zip IV gene GaHOX1 from cotton is a functional homologue of the Arabidopsis GLABRA2. Physiologia Plantarum 134: 174-182. Mao YB, Cai WJ, Wang JW, Hong GJ, Tao XY, Wang LJ, Huang YP, Chen XY. (2007) Silencing a cotton bollworm P450 gene by plant-mediated RNAi impairs larval tolerance to gossypol. Nature Biotechnology 25: 1307-1313. Gou JY, Wang LJ, Chen SP, Hu WL, Chen XY. (2007) Gene expression and metabolite profiles of cotton fiber during cell elongation and secondary cell wall synthesis. Cell Research 17: 422-434. Wang S, Wang JW, Yu N, Li CH, Luo B, Gou JY, Wang LJ, Chen XY. (2004) Control of plant trichome development by a cotton fiber MYB gene. The Plant Cell 16: 2323-2334.
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