吲哚-3-乙酸（又称IAA或生长素）,在植物生长发育中具有重要的调控作用,其作用主要通过信号转导途径来完成。生长素受体是其信号转导的关键元件之一。本研究通过RACE克隆,获得了茶树中生长素受体CsTIR1基因的cDNA全长序列（NCBI登录号：JX050147）。CsTIR1序列全长2β315βbp,含1β746βbp的完整开放阅读框,编码581个氨基酸,预测分子量65.18βkD,理论等电点（pI）5.64。茶树CsTIR1与烟草TIR1的相似性最高达82%,亲缘关系最近。CsTIR1含有1个F-box结构域和6个LRR结构域,三级结构形如“蘑菇状”。CsTIR1在茶树的根、茎、叶和花中具有组织表达特异性;其表达受IAA诱导,3种不同浓度的IAA均能诱导CsTIR1上调表达,且在50βμmol·L-1浓度下表达量最大;ABA、GA3、MeJA和BR等激素也能够显著上调其表达;CsTIR1在越冬休眠芽中的表达量低,在活跃期中上调表达。
Indole-3-acetic acid (IAA or auxin), functioning via its signal transduction, plays a pivotal role in plant growth and development regulation. Transport inhibitor response 1 (TIR1) protein, an auxin receptor, is one of the most critical components in IAA signaling pathway. The full-length cDNA sequence of CsTIR1 gene was obtained by using RACE technique, and submitted to GenBank with accession number JX050147. The CsTIR1 cDNA length was 2β315βbp, and contained a 1β746βbp open reading frame (ORF), encoding 581 amino acid residues. The molecular weight and theoretic isoelectric point of CsTIR1 protein are 65.18 kD and 5.64, respectively. In addition, CsTIR1 protein had the highest sequence similarity about 82% and the closest genetic relationship to Nicotiana tabacum. The CsTIR1 was predicted to contain one F-box and six leucine-rich-repeat (LRR) domains, which forming the ‘stem’ and ‘cap’, respectively. And its tertiary structure is shaped as a mushroom. Semi-quantitative RT-PCR results suggested that CsTIR1 expression showed a tissue-specificity among root, stems, leaves and flowers. The further investigation indicated that the transcript of CsTIR1 was regulated by phytohormones. In a time-course assay, it was found that CsTIR1 was significantly up-regulated when tea plant treated with three different IAA concentration and various plant hormones (ABA, GA3, MeJA and BR), and showed the highest expression level under 50 μmol·L-1 IAA concentration. Finally, the expression of CsTIR1 was detected in bud dormancy-active cycle during winter and CsTIR1 showed a low transcription level in dormant buds but expressed abundantly in active buds.
[1] Si-Ammour A, Windels D, Arn-Bouldoires E, et al. miR393 and secondary siRNAs regulate expression of the TIR1/AFB2 auxin receptor clade and auxin-related development of Arabidopsis leaves[J]. Plant Physiol, 2011, 157(2): 683-691.
[2] Woodward A W, Bartel B.Auxin: regulation, action, and interaction[J]. Ann Bot, 2005, 95(5):707-735.
[3] Dharmasiri N, Dharmasiri S, Estelle M.The F-box protein TIR1 is an auxin receptor[J]. Nature, 2005, 435(7041): 441-445.
[4] Kepinski S, Leyser O.The Arabidopsis F-box protein TIR1 is an auxin receptor[J]. Nature, 2005, 435(7041): 446-451.
[5] Woodward A W, Bartel B.A receptor for auxin[J]. Plant Cell, 2005, 17(9): 2425-2429.
[6] Tan X, Calderon-Villalobos L I, Sharon M, et al. Mechanism of auxin perception by the TIR1 ubiquitin ligase[J]. Nature, 2007, 446(7136): 640-645.
[7] Bishopp A, Mahonen A P, Helariutta Y.Signs of change: hormone receptors that regulate plant development[J]. Development, 2006, 133(10): 1857-1869.
[8] Ren Z, Li Z, Miao Q, et al. The auxin receptor homologue in Solanum lycopersicum stimulates tomato fruit set and leaf morphogenesis[J]. J Exp Bot, 2011, 62(8): 2815-2826.
[9] Tian Y, Zhang C, Yang H, et al. Molecular cloning and characterization of a TRANSPORT INHIBITOR RESPONSE 1 (TIR1) from Nicotiana tabacum[J]. Russ J of Plant Physiol, 2011, 58(1): 149-156.
[10] Cui L, Zhang T, Li J.Cloning and expression analysis of Cs-TIR1/AFB2: the fruit development-related genes of cucumber (Cucumis sativus L.)[J]. Acta Physiol Plant, 2013, 36(1): 139-149.
[11] 岳川, 曾建明, 章志芳, 等. 茶树中植物激素研究进展[J]. 茶叶科学, 2012, 32(5): 382-392.
[12] Meier A R, Saunders M R, Michler C H.Epicormic buds in trees: a review of bud establishment, development and dormancy release[J]. Tree Physiol, 2012, 32(5): 565-584.
[13] 王新超. 茶树越冬芽休眠与萌发相关基因的分离与表达分析[D]. 北京: 中国农业科学院, 2011: 25-38.
[14] 王新超, 马春雷, 杨亚军, 等. 生长素相关基因在茶树腋芽冬季休眠不同生长阶段的表达分析[J]. 茶叶科学, 2012, 32(6): 509-516.
[15] 王新超, 马春雷, 杨亚军, 等. 茶树生长素抑制蛋白基因CsARP1的克隆与表达分析[J]. 核农学报, 2011, 25(5): 910-921.
[16] 郝心愿, 曹红利, 杨亚军, 等. 茶树生长素响应因子基因CsARF1的克隆与表达分析[J]. 作物学报, 2013, 39(3): 389-397.
[17] 黄亚辉, 粟本文, 曾贞, 等. 茶树春梢萌动生育期内源激素变化的研究[J]. 茶叶通讯, 2002, 29(2): 24-27.
[18] 黄亚辉, 粟本文, 郑红发, 等. 茶树春梢萌动期间内源激素含量的变化(简报)[J]. 植物生理学通讯, 2001, 37(4): 306-307.
[19] 潘根生. 茶树生育与内源生长素和脱落酸的关系[J]. 茶叶科学, 1991, 11(1): 25-28.
[20] 潘根生, 钱利生, 沈生荣, 等. 茶树新梢生育的内源激素水平及其调控机理(第二报): 茶树休眠与内源激素的关系[J]. 茶叶, 2000, 26(4): 200-204.
[21] 吴彩, 方兴汉. 茶树解除休眠前后体内激素等物质变化及锌的积极影响[J]. 作物学报, 1993, 19(2): 179-184.
[22] Wang X C, Zhao Q Y, Ma C L, et al. Global transcriptome profiles of Camellia sinensis during cold acclimation[J]. BMC Genomics, 2013, 14: 415.
[23] 岳川, 曾建明, 曹红利, 等. 茶树赤霉素受体基因CsGID1a的克隆与表达分析[J]. 作物学报, 2013, 39(4): 599-608.
[24] Badescu G O, Napier R M.Receptors for auxin: will it all end in TIRs?[J]. Trends Plant Sci, 2006, 11(5): 217-223.
[25] Shan X, Yan J, Xie D.Comparison of phytohormone signaling mechanisms[J]. Curr Opin Plant Biol, 2012, 15(1): 84-91.
[26] Fu X, Harberd N P.Auxin promotes Arabidopsis root growth by modulating gibberellin response[J]. Nature, 2003, 421(6924): 740-743.
[27] Horvath D P, Anderson J V, Chao W S, et al. Knowing when to grow: signals regulating bud dormancy[J]. Trends Plant Sci, 2003, 8(11): 534-540.
[28] Tanino K K.Hormones and Endodormancy Induction in Woody Plants[J]. J Crop Improve, 2004, 10(1/2): 157-199.
浙公网安备 33019902000101号 
