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 Focus on the effects of plant hormone and functional genomics studies of seed development, with the emphasis on the auxin and brassinosteroid (effects and relevant signal transduction); functions of phosphatidylinositol signaling pathway and cross-talk of which with plant hormones; effects of transcription factors, receptor-like kinase and miRNAs in seed development; molecular regulation of fatty acid metabolism.
Lab Homepage: http://www.plantsignal.cn
Principal Investigator: Dr. Hong-Wei Xue, Professor. Email: hwxue@sibs.ac.cn; Zhi-Hong Xu, Professor, Academician
Staff: Gong-Hao Jiang, Research Associate; Si-Shi Shen, Senior Technician; Mei-Qing Xing, Research Assistant; Li Song, Research Assistant; Shu-Ping Xu, Senior Technician (emeritus)
Postdoctoral Fellow: Dr. Jun-Feng Zhang
Graduate Students: Ya-Nan Yang; Yu Mei; Qiu-Ming Shi; Lin-Lin Gao; Fang-Fang Fu; Liang-Jiao Xue; Xu Chen; Xin-Xin Han; Cheng Dai; Guo-Zhang Wu; Ling Chang; Jing-Jing Zhang; Xi Yang; Bi-Qing Wen; Yong Tang; Lin-Lin Yin; Jun Wang; Jing-Jing Xiang; Hong-Bo Gao; Peng Li; Wei Wang; Xiao-Yi Zhou; Yu-Jia Chu; Hua Zhang; Si-Yue Wang; Li-Bi Lin; Jia-Qiang Dong
Graduated Students: Yuan Wang, 2004 (PhD); Qian Xu, 2004 (PhD); Shu-Qing Zhao, 2004 (PhD); Ya Niu, 2004 (MS)
An Inositol Polyphosphate 5-Phosphatase Functions in PHOTOTROPIN1 Signaling in Arabidopsis by Altering Cytosolic Ca2+
Arabidopsis inositol polyphosphate 5-phosphatase (5PTase) encodes a WD40-containing type II 5PTase and plays a role in hormone-mediated cotyledon vein development. We further show that 5PTase13 is also involved in blue light responses in Arabidopsis. Compared with that in darkness, the expression of 5PTase13 as suppressed by blue light irradiation, and disruption of the gene resulted in shortened hypocotyls and expanded cotyledons. Genetic analysis showed that 5PTase13 acted independently from CRYPTOCHROME1 and CONSTITUTIVE PHOTOMORPHOGENIC1 but interacted functionally with PHOTOTROPIN1 (PHOT1). The expression level of 5PTase13 was significantly enhanced in phot1 single or phot1 phot2 double mutants under blue light, and suppression of 5PTase13 expression rescued the elongated hypocotyls in the phot1 or phot1 phot2 mutants. Further analysis showed that the blue light–induced elevation of cytosolic Ca2+ was inhibited in the phot1 mutant but enhanced in the 5pt13 mutant, suggesting that 5PTase13 antagonizes PHOT1-mediated effects on calcium signaling under blue light.
Characterization and Expression Profiles of miRNAs in Rice Seeds
Small RNAs (sRNAs) are common and effective modulators of gene expression in eukaryotic organisms. To characterize the sRNAs expressed during rice seed development, massively parallel signature sequencing (MPSS) was performed, resulting in the obtainment of 797 399 22-nt sequence signatures, of which 111 161 are stinct ones. Analysis on the distributions of sRNAs on chromosomes showed that most sRNAs originate from interspersed repeats that mainly consist of transposable elements, suggesting the major function of sRNAs in rice seeds is transposon silencing. Through integrative analysis, 26 novel miRNAs and 12 miRNA candidates were identified. Further analysis on the expression profiles of the known and novel miRNAs through hybridizing the generated chips revealed that most miRNAs were expressed preferentially in one or two rice tissues. Detailed comparison of the expression patterns of miRNAs and corresponding target genes revealed the negative correlation between them, while few of them are positively correlated. In addition, differential accumulations of miRNAs and corresponding miRNA*s suggest the functions of miRNA*s other than being passenger strands of mature miRNAs, and in regulating the miRNA functions.
Major Publications:
Chen X, Lin WH, Wang Y, Luan S, Xue HW*. (2008) An Inositol polyphosphate 5-phosphatase functions in phototropin 1 signaling by altering cytosolic Ca2+. The Plant Cell 20: 353-366. Wu GZ, Shi QM, Niu Y, Xing MQ and Xue HW*. (2008) Shanghai RAPESEED Database: a resource for functional genomics studies of seed development and fatty acid metabolism of Brassica. Nucleic Acids Research 36: D1044-D1047. Li G, and Xue HW*. (2007) Arabidopsis PLDζ2 regulates vesicle trafficking and is required for auxin response. The Plant Cell 19: 281-295. Lou Y, Gou JY, and Xue HW*. (2007) AtPIP5K9, an Arabidopsis phosphatidylinositol monophosphate kinase, interacts with a cytosolic invertase to negatively regulate sugar-mediated root growth. The Plant Cell 19: 163-181. Duan K, Li L, Hu P, Xu SP, Xu ZH and Xue HW*. (2006) A brassinolide-suppressed rice MADS-box transcription factor, OsMDP1, has a negative regulatory role in BR signaling. The Plant J. 47: 519-531.
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