余義和,李秀珍,郭大龍,張會靈,楊英軍,李學(xué)強,張國海
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葡萄類鈣調(diào)磷酸酶B亞基互作蛋白激酶VvCIPK10的特性與表達(dá)
余義和,李秀珍,郭大龍,張會靈,楊英軍,李學(xué)強,張國海
(河南科技大學(xué)林學(xué)院,河南洛陽 471003)
【目的】在葡萄中克隆絲蘇氨酸蛋白激酶,分析其激酶特性和在逆境脅迫下的表達(dá)模式,為進(jìn)一步研究該基因參與逆境脅迫的分子功能,探討葡萄抗逆分子機制提供理論依據(jù)?!痉椒ā坷秒娮涌寺〖夹g(shù)獲得序列,設(shè)計特異引物進(jìn)行RT-PCR反應(yīng),對克隆到的序列進(jìn)行開放閱讀框和保守結(jié)構(gòu)域分析;構(gòu)建原核表達(dá)載體,轉(zhuǎn)化表達(dá)菌株后用IPTG進(jìn)行誘導(dǎo)表達(dá),收集菌體后裂解細(xì)胞,制備蛋白上樣液,SDS-PAGE電泳對表達(dá)產(chǎn)物進(jìn)行分析,同時對融合蛋白進(jìn)行可溶性分析;IPTG大量誘導(dǎo)表達(dá)融合蛋白,收集菌體后進(jìn)行超聲破碎細(xì)胞,用麥芽糖結(jié)合蛋白純化柱純化MBP-VvCIPK10融合蛋白,SDS-PAGE電泳進(jìn)行分析;純化后的融合蛋白與體外自磷酸化緩沖液進(jìn)行自磷酸化反應(yīng),反應(yīng)后SDS-PAGE電泳,壓磷屏檢測體外自磷酸化反應(yīng);構(gòu)建重組瞬時表達(dá)載體pBI221-GFP/VvCIPK10;分離擬南芥原生質(zhì)體,通過PEG介導(dǎo)的瞬時轉(zhuǎn)化方法將重組表達(dá)載體pBI221-GFP/ VvCIPK10轉(zhuǎn)化至原生質(zhì)體;通過基因槍介導(dǎo)的轉(zhuǎn)化方法將重組表達(dá)載體pBI221-GFP/VvCIPK10轉(zhuǎn)化至洋蔥表皮細(xì)胞,培養(yǎng)16 h后用激光共聚焦顯微鏡進(jìn)行熒光信號檢測;選擇生長相對一致且健壯的葡萄植株,于干旱、低溫和鹽脅迫處理后不同時間取樣,同時在田間取葡萄不同組織樣品,實時熒光定量PCR檢測在葡萄不同組織中的表達(dá)以及在不同逆境脅迫下的表達(dá)模式。【結(jié)果】PCR克隆獲得葡萄全長為1 357 bp,5′端非編碼區(qū)為30 bp,3′端非編碼區(qū)為156 bp,開放閱讀框為1 171 bp,編碼436個氨基酸,理論等電點為8.59,分子量為48.7 kDa。保守結(jié)構(gòu)域預(yù)測分析顯示該蛋白5′端具有一個激酶結(jié)構(gòu)域,3′末端具有一個PPI結(jié)構(gòu)域和一個NAF結(jié)構(gòu)域。BLSATP分析表明葡萄VvCIPK10與桃樹CIPK(XP_007205151)一致性最高(74%)。重組表達(dá)載體pMAL-C5X/VvCIPK10在大腸桿菌中經(jīng)誘導(dǎo)表達(dá)獲得與理論分子量(43 kDa+48.7 kDa)相一致的融合蛋白。MBP-VvCIPK10融合蛋白經(jīng)柱純化后獲得單一的蛋白條帶,VvCIPK10的自磷酸化活性依賴于Mn2+,不依賴于Mg2+和Ca2+,EDTA可以抑制VvCIPK10的自磷酸化活性。亞細(xì)胞定位結(jié)果顯示,VvCIPK10定位在細(xì)胞核、細(xì)胞膜和細(xì)胞質(zhì)。在葡萄各個組織中均有表達(dá),主要在葡萄根和葉片中大量表達(dá),葡萄莖、花序、果實和卷須中的表達(dá)量較低。在干旱、低溫和鹽脅迫處理后,呈現(xiàn)受誘導(dǎo)表達(dá)模式。的表達(dá)在低溫脅迫后6 h達(dá)到峰值,干旱和鹽脅迫后2 h即達(dá)到峰值?!窘Y(jié)論】葡萄能夠響應(yīng)干旱、低溫和鹽脅迫,推測在葡萄抗非生物逆境脅迫中具有重要作用。
葡萄;類鈣調(diào)磷酸酶B亞基;絲蘇氨酸蛋白激酶;;表達(dá)分析
【研究意義】葡萄作為重要果樹在世界范圍內(nèi)廣泛栽培。葡萄栽培過程中常遇到各種各樣的非生物逆境脅迫,導(dǎo)致葡萄生長發(fā)育受阻和果實品質(zhì)降低,嚴(yán)重影響葡萄生產(chǎn)和經(jīng)濟(jì)效益[1]。在葡萄中挖掘逆境脅迫相關(guān)基因并分析關(guān)鍵基因功能,對于培育抗逆能力強的葡萄新種質(zhì)具有重要的理論意義和應(yīng)用價值?!厩叭搜芯窟M(jìn)展】類鈣調(diào)磷酸酶B亞基蛋白(Calcineurin B-like protein, CBL)是植物鈣信號轉(zhuǎn)導(dǎo)途徑中的重要鈣感受器之一,在鈣信號介導(dǎo)的植物逆境脅迫響應(yīng)過程中發(fā)揮重要作用[2-5]。CBL互作蛋白激酶(CBL- interacting protein kinase,CIPK)編碼絲/蘇氨酸蛋白激酶,與CBL相互作用形成蛋白激酶復(fù)合物來響應(yīng)逆境脅迫,通過感受細(xì)胞內(nèi)Ca2+濃度變化來調(diào)節(jié)下游逆境相關(guān)基因的表達(dá),實現(xiàn)對逆境脅迫的轉(zhuǎn)錄調(diào)控[6-8]。研究人員利用正向遺傳學(xué)在擬南芥中篩選到一系列的鹽敏感突變體(salt overly sensitive,SOS),SOS2編碼絲/蘇氨酸蛋白激酶即AtCIPK24,SOS3編碼CBL蛋白即AtCBL4,二者通過相互作用協(xié)同應(yīng)對高鹽逆境脅迫[9-10]。TaCIPK29是在小麥中克隆的一個絲/蘇氨酸蛋白激酶,在轉(zhuǎn)錄水平可以響應(yīng)干旱、NaCl和低溫處理,在煙草中過量表達(dá)增強了轉(zhuǎn)基因植株的耐鹽性[11]。油菜轉(zhuǎn)錄本在NaCl、滲透脅迫以及ABA處理后急劇增加,啟動子活性受NaCl、甘露醇以及ABA的誘導(dǎo),轉(zhuǎn)的擬南芥植株增強了對NaCl的耐受能力[12]。蘋果受鹽、低溫和干旱脅迫誘導(dǎo)表達(dá),在擬南芥中過量表達(dá)可以增強轉(zhuǎn)基因植株的抗鹽、干旱和低溫的能力[13]。鷹嘴豆轉(zhuǎn)錄本受鹽、低溫和干旱等逆境脅迫的誘導(dǎo)表達(dá),在擬南芥突變體中過量表達(dá)可以恢復(fù)NaCl敏感表型[14]。這些研究表明CIPK不僅參與了植物對鹽、低溫以及干旱等逆境脅迫反應(yīng),還說明不同物種中的基因功能保守?!颈狙芯壳腥朦c】是葡萄中K+通道Shaker家族的一個成員,與擬南芥高度同源[15]。VvCIPK23可以通過調(diào)控來實現(xiàn)K+在干旱條件下進(jìn)入果實組織中,進(jìn)而調(diào)節(jié)果實酸度[15]。能否直接參與葡萄逆境脅迫響應(yīng)還不清楚?!緮M解決的關(guān)鍵問題】本研究擬在葡萄中克隆并進(jìn)行序列分析,對其是否具有激酶特性進(jìn)行鑒定,并探討該基因在不同逆境脅迫條件下的表達(dá)模式,為進(jìn)一步鑒定葡萄在逆境脅迫下的生物學(xué)功能及其抗逆分子機制提供理論依據(jù)。
試驗于2015年在河南科技大學(xué)進(jìn)行。
1.1 植物材料與試驗處理
于2015年在河南科技大學(xué)試驗基地取樣。植物材料為4—6年生籬架栽培‘京秀’葡萄,果實于轉(zhuǎn)色期取樣,根系(第一側(cè)根)、莖(第3—4片新展開葉之間的莖段)、葉(第3—4片新展開葉)、卷須(新生第1卷須)和花序在盛花前期采樣。取樣后液氮速凍,及時提取總RNA,反轉(zhuǎn)錄為cDNA后-80℃條件下保存?zhèn)溆谩?/p>
‘京秀’葡萄組培苗繼代培養(yǎng)20 d,選擇生長健壯一致的瓶苗用于逆境脅迫處理。組培苗正常生長條件:溫度為(24±1)℃、相對濕度為75%、光周期為光照14 h/黑暗10 h。從培養(yǎng)基中拔出幼苗置于培養(yǎng)皿(不蓋蓋子),暴露于正常生長條件下進(jìn)行干旱處理。將瓶苗置于4℃條件下進(jìn)行低溫處理。在培養(yǎng)瓶中加入20 mL 100 mmol·L-1的NaCl溶液進(jìn)行鹽脅迫處理。正常培養(yǎng)條件下的組培苗作為干旱和低溫脅迫的對照。在培養(yǎng)瓶中加入20 mL蒸餾水作為鹽脅迫的對照。試驗組和對照組分別于處理后0、2、6、12和24 h取樣。取樣后液氮速凍,提取總RNA后反轉(zhuǎn)錄為cDNA,-80℃條件下保存?zhèn)溆谩?/p>
1.2 總RNA提取與反轉(zhuǎn)錄
葡萄不同組織總RNA提取按照plus植物總RNA提取試劑盒(天根生化科技有限公司,北京)說明書進(jìn)行。反轉(zhuǎn)錄按照PrimeScriptII 1st Strand cDNA Synthesis Kit(TaKaRa,大連)說明書進(jìn)行。
1.3的克隆與序列分析
以葡萄的部分cDNA序列為種子序列(GenBank登錄號:NM_001281285),在NCBI網(wǎng)站的EST數(shù)據(jù)庫中進(jìn)行BLAST檢索,下載同源性在95%以上的EST序列,利用SeqMan軟件進(jìn)行拼接,獲得葡萄的電子序列。依據(jù)此電子序列,用Primer Premier 5.0軟件設(shè)計特異引物P1:5′-GGAGAG AGGGGTGTTCGATCTCTG-3′和P2:5′-GCGCTAAC CAGAACATTTAATCGC-3′。用PrimeSTAR? Max DNA Polymerase進(jìn)行PCR反應(yīng),具體反應(yīng)體系和反應(yīng)程序參考使用說明書。PCR產(chǎn)物經(jīng)1.2%的瓊脂糖凝膠電泳,回收目標(biāo)片段,連接至pMD19-T載體,轉(zhuǎn)化TOP10感受態(tài)細(xì)胞,經(jīng)抗生素和藍(lán)白斑篩選,挑取陽性克隆送公司測序驗證。利用NCBI網(wǎng)站的ORF Finder在線軟件分析的開放閱讀框。用NCBI網(wǎng)站的BLASTn和BLASTp在線軟件進(jìn)行同源性分析。用ExPASy網(wǎng)站的PROSITE和NCBI網(wǎng)站的CD search進(jìn)行保守結(jié)構(gòu)域預(yù)測分析。用ExPASy網(wǎng)站的Compute pI/Mw程序分析氨基酸序列的分子量和理論等電點。
1.4 原核表達(dá)載體和瞬時表達(dá)載體構(gòu)建
根據(jù)葡萄開放閱讀框設(shè)計引物,構(gòu)建原核表達(dá)載體用引物P3:5′-GGGATGCCAG AGATCGAACGCGGCTC-3′(下劃線為I酶切位點)和P4:5′-GGGTTAATCGATCAATTTG AACCCCG-3′(下劃線為R I酶切位點),構(gòu)建瞬時表達(dá)載體用引物P5:5′-AGCAATGCCAG AGATCGAACGCGGCTC-3′(下劃線為I酶切位點)和P6:5′-ATGCTTTAATCGATCAATTT GAACCCCG-3′(下劃線為I酶切位點)。以pMD19-T/VvCIPK10質(zhì)粒為模板,用PrimeSTAR? Max DNA Polymerase進(jìn)行PCR反應(yīng)。用I和R I雙酶切PCR產(chǎn)物和pMAL-C5X原核表達(dá)載體,用I和I雙酶切PCR產(chǎn)物和pBI221-GFP瞬時表達(dá)載體,分別回收目標(biāo)片段后進(jìn)行連接反應(yīng),轉(zhuǎn)化TOP10感受態(tài)細(xì)胞,經(jīng)抗性篩選后挑取陽性克隆,提取質(zhì)粒用雙酶切進(jìn)行鑒定,含有目標(biāo)片段的重組載體經(jīng)測序驗證。
1.5 原核表達(dá)與蛋白純化
重組載體pMAL-C5X/VvCIPK10轉(zhuǎn)化BL21感受態(tài)細(xì)胞,經(jīng)氨芐青霉素(100 mg·L-1)篩選,挑取單克隆進(jìn)行PCR檢測。陽性克隆接種至LB液體培養(yǎng)基中(含100 mg·L-1氨芐青霉素),37℃振蕩培養(yǎng)過夜。次日以1﹕50的比例接種至新鮮LB液體培養(yǎng)基中,37℃振蕩培養(yǎng)至OD600值為0.6左右,加入終濃度為0.1 mmol·L-1的IPTG誘導(dǎo)培養(yǎng)4 h,以不加IPTG誘導(dǎo)的pMAL-C5X/VvCIPK10和pMAL-C5X空載體作為對照。5 000 r/min離心2 min收集菌體,加入等體積的2倍上樣緩沖液懸浮細(xì)胞,沸水浴5 min,樣品冷卻后5 000 r/min離心1 min,取適量樣品進(jìn)行SDS-PAGE(濃縮膠濃度為5%,分離膠濃度為12%)電泳分析。PBS(pH 7.4)緩沖液重懸誘導(dǎo)表達(dá)的菌體,在冰浴條件下超聲波(100 V電壓,5 S間隔)處理至菌液粘稠透亮,制備上樣液后經(jīng)SDS-PAGE電泳,進(jìn)行蛋白可溶性分析。
融合蛋白純化按照pMALTM融合蛋白純化系統(tǒng)(NEB)說明書進(jìn)行。菌液經(jīng)IPTG誘導(dǎo)后,用50 ml離心管收集菌體,10 ml Column Buffer重懸沉淀,于-20℃冷凍過夜。冰浴中解凍后用超聲破碎機處理,4℃條件下12 000 r/min離心20 min,上清液中加入5倍體積的Column Buffer即為粗提液。將直鏈淀粉樹脂倒入柱子中,用5倍柱體積的Column Buffer洗柱子,然后加入粗提液,12倍柱體積的Column Buffer洗柱子,流速為10 ml·min-1,最后用Column Buffer+10 mmol·L-1麥芽糖洗脫融合蛋白,收集流出液,檢測不同收集管中的蛋白濃度。根據(jù)濃度需要混合不同收集管的融合蛋白。
1.6 蛋白激酶活性分析
取純化過的融合蛋白4 μg,加入0.4 μL 1 mol·L-1Tris-HCl(pH 8.0),金屬離子10 mmol,ddH2O補齊至9.5 μL。加入0.5 μL 5 μCi γ-32P-ATP后充分混勻,30℃溫浴30 min。加入等體積的2倍上樣緩沖液終止反應(yīng),沸水浴5 min,樣品冷卻后SDS-PAGE電泳。電泳后轉(zhuǎn)移至PVDF膜,保鮮膜包好后進(jìn)行壓磷屏。
1.7 亞細(xì)胞定位
大量抽提重組質(zhì)粒pBI221-GFP/VvCIPK10,純化后備用。參照Yoo等的方法制備擬南芥原生質(zhì)體[16],采用PEG介導(dǎo)的方法將重組質(zhì)粒轉(zhuǎn)化原生質(zhì)體。取洋蔥5—6層鱗莖,剝?nèi)?nèi)表皮置于培養(yǎng)皿中,黑暗培養(yǎng)24 h。金粉包裹重組質(zhì)粒,用基因槍介導(dǎo)的方法轉(zhuǎn)化洋蔥表皮細(xì)胞。轉(zhuǎn)化后的材料置于25℃條件下光照培養(yǎng)16 h,用激光共聚焦顯微鏡(ZEISS LSM-510 META,Germany)進(jìn)行觀察。轉(zhuǎn)化空載體pBI121-GFP作為對照。
1.8 實時熒光定量PCR
根據(jù)序列設(shè)計引物P7:5′-CCGTCGGT ATTTCCAGCAG-3′和引物P8:5′-CTTTCGCCCCAT CGTAGC-3′。(GenBank登錄號:AY680701)基因作為內(nèi)參基因,設(shè)計引物P9:5′-GATTCTGGT GATGGTGTGAGT-3′和引物P10:5′-GACAATTTC CCGTTCAGCAGT-3′。提取葡萄不同組織和逆境處理后不同時間葉片的總RNA,反轉(zhuǎn)錄cDNA后稀釋50倍,在Bio-Rad IQ5 Real-Time PCR Detection System(Bio-Rad Laboratories, Hercules, CA)進(jìn)行實時熒光定量PCR。PCR反應(yīng)體系和反應(yīng)程序按照SYBR?Premix Ex TaqTMII說明書進(jìn)行。采用2-ΔΔCt法對結(jié)果進(jìn)行相對定量分析[17],每個樣品重復(fù)3次。
1.9 數(shù)據(jù)處理與分析
采用Excel進(jìn)行數(shù)據(jù)處理和作圖,用DPS 7.05軟件進(jìn)行顯著性檢驗。
2.1 葡萄類鈣調(diào)磷酸酶B互作蛋白激酶的克隆與序列分析
根據(jù)電子克隆獲得的基因序列設(shè)計引物,以‘京秀’葡萄葉片cDNA為模板進(jìn)行PCR擴增,結(jié)果得到與預(yù)期片段大小一致的產(chǎn)物。測序結(jié)果表明5′端非編碼區(qū)為30 bp,3′端非編碼區(qū)為156 bp,開放閱讀框為1 171 bp,編碼436個氨基酸,理論等電點為8.59,分子量為48.7 kDa(GenBank登錄號為KT001237)。保守結(jié)構(gòu)域預(yù)測分析顯示該蛋白5′端具有一個激酶結(jié)構(gòu)域,3′末端具有一個PPI結(jié)構(gòu)域,中間具有一個NAF結(jié)構(gòu)域。經(jīng)BLSATP分析顯示,所獲得的葡萄VvCIPK10蛋白與桃樹(XP_007205151)、蘋果(XP_008344764)、草莓(XP_004302572)和擬南芥(NP_180595)在氨基酸水平上一致性分別達(dá)到74%、72%、70%和65%。
2.2 VvCIPK10的原核表達(dá)
以葡萄葉片cDNA為模板,用特異引物擴增的開放閱讀框,通過T/A克隆連接到pMD19-T載體上,獲得重組質(zhì)粒pMD19-T/VvCIPK10,測序驗證開放閱讀框序列。用R I和d III雙酶切重組載體pMD19-T/VvCIPK10和原核表達(dá)載體pMAL-C5X,分別回收開放閱讀框目標(biāo)片段和pMAL-C5X載體骨架片段,連接后形成重組載體pMAL-C5X/VvCIPK10。用R I和d III雙酶切重組載體pMAL-C5X/VvCIPK10,結(jié)果獲得與開放閱讀框序列大小一致的目標(biāo)片段(圖1),說明原核表達(dá)載體構(gòu)建完成,可用于下一步原核表達(dá)試驗。
M:DNA分子量標(biāo)準(zhǔn);1:重組質(zhì)粒pMAL-C5X/VvCIPK10;2:EcoR I和Hind III雙酶切重組質(zhì)粒pMAL-C5X/VvCIPK10
將重組載體pMAL-C5X/VvCIPK10轉(zhuǎn)化至大腸桿菌BL21,經(jīng)菌液PCR檢測,挑取陽性克隆搖菌培養(yǎng),用0.1 mmol·L-1的IPTG誘導(dǎo)表達(dá)后進(jìn)行SDS-PAGE分析。含有pMAL-C5X空載體的菌株經(jīng)誘導(dǎo)后,在43 kDa的位置產(chǎn)生一條目標(biāo)帶,說明麥芽糖結(jié)合蛋白正確表達(dá)。含有重組載體pMAL-C5X/VvCIPK10的菌株經(jīng)誘導(dǎo)后,在90 kDa左右的位置產(chǎn)生一條目標(biāo)帶,菌體經(jīng)超聲破碎后上清液在相同位置也有目標(biāo)條帶(圖2-A),說明正確表達(dá)并以可溶性蛋白形式表達(dá)。將含有可溶性蛋白的上清液用親和淀粉樹脂柱純化,SDS-PAGE結(jié)果顯示在90 kDa左右的位置產(chǎn)生單一目標(biāo)帶(圖2-B),說明純化得到成分單一的MBP-VvCIPK融合蛋白。
A:葡萄VvCIPK10在大腸桿菌中的誘導(dǎo)表達(dá)。M:蛋白質(zhì)分子量標(biāo)準(zhǔn);1:未經(jīng)IPTG誘導(dǎo)的對照;2:IPTG誘導(dǎo)的對照;3:未經(jīng)IPTG誘導(dǎo)的重組菌;4:IPTG誘導(dǎo)重組菌的總蛋白;5:IPTG誘導(dǎo)重組菌的可溶性蛋白。B:MBP-VvCIPK10融合蛋白的純化泳道1:IPTG誘導(dǎo)的對照;泳道2:IPTG誘導(dǎo)重組菌的可溶性蛋白;泳道3:純化后的MBP-VvCIPK10融合蛋白
2.3 VvCIPK10的激酶特性分析
VvCIPK10具有激酶結(jié)構(gòu)域,為分析該蛋白是否具有激酶特性,用純化獲得的MBP-VvCIPK10融合蛋白進(jìn)行體外自磷酸化酶活性分析。結(jié)果表明VvCIPK10的自磷酸化酶活性依賴于Mn2+,但不依賴于Mg2+和Ca2+,添加金屬離子螯合劑可以抑制VvCIPK10的自磷酸化酶活性(圖3)。
圖3 VvCIPK10的自磷酸化酶活性分析
2.4 VvCIPK10的亞細(xì)胞定位
轉(zhuǎn)化空載體pBI221-GFP的原生質(zhì)體和洋蔥表皮細(xì)胞的細(xì)胞核、細(xì)胞質(zhì)和細(xì)胞膜上存在熒光信號,轉(zhuǎn)化重組載體pBI221-GFP/VvCIPK10的原生質(zhì)體和洋蔥表皮細(xì)胞的細(xì)胞核、細(xì)胞質(zhì)和細(xì)胞膜上存在熒光信號。這說明VvCIPK10定位在細(xì)胞核、細(xì)胞質(zhì)和細(xì)胞膜(圖4)。
A:葡萄VvCIPK10在擬南芥原生質(zhì)體中的亞細(xì)胞定位;B:葡萄VvCIPK10在洋蔥表皮細(xì)胞中的亞細(xì)胞定位
2.5的表達(dá)分析
在葡萄各個組織中均有表達(dá),但表達(dá)量在不同組織之間存在差異。在葡萄莖、花序、果實和卷須中的表達(dá)量較低。在葡萄根和葉中大量表達(dá),與莖、花序、果實和卷須中的表達(dá)量相比存在顯著差異(<0.05)。為探討對不同逆境處理的響應(yīng)模式,用低溫、干旱和鹽脅迫處理葡萄幼苗后,檢測葉片中的表達(dá)變化。的表達(dá)在低溫處理后2 h開始增加,6 h達(dá)到最大值,然后表達(dá)量降低,到24 h表達(dá)量又恢復(fù)到一個較高的水平。的表達(dá)量在干旱脅迫后2 h快速增加,達(dá)到一個峰值,然后在不同時間點都維持較高的表達(dá)水平。鹽脅迫后的表達(dá)量迅速增加,在2 h就達(dá)到峰值,6 h下降至較低的表達(dá)水平,在12—24 h呈現(xiàn)持續(xù)增加的模式(圖5)。
A:VvCIPK10在葡萄不同組織中的表達(dá)分析;B—D:葡萄VvCIPK10對干旱、低溫和鹽脅迫的響應(yīng)。不同小寫字母表示差異顯著(P<0.05)
植物CBI-CIPK網(wǎng)絡(luò)信號系統(tǒng)在逆境脅迫響應(yīng)過程中具有重要作用[17-18]。CBL蛋白是植物所特有的小分子Ca2+感受器。CIPK是能夠與CBL相互作用的絲/蘇氨酸蛋白激酶,屬于第3類的SnRK3(SNF1-related protein kinase 3)[19-20]。在擬南芥中,AtCBL4/SOS3與AtCIPK24/SOS2相互作用,并與NHX7/SOS1共同組成SOS信號系統(tǒng)參與擬南芥對鹽脅迫的調(diào)控[9-10]。已有的研究結(jié)果表明的表達(dá)模式主要分兩種:一是同一物種內(nèi)不同的對不同的環(huán)境刺激呈現(xiàn)不同的響應(yīng)模式[21-22];二是不同物種中的同源對不同刺激的響應(yīng)模式[23-25]。擬南芥可以增強轉(zhuǎn)基因植株對干旱和鹽脅迫的抗逆性,但不能明顯改善轉(zhuǎn)基因植株的抗低溫能力[26-27]。蘋果與高度同源,可以對干旱、低溫和鹽脅迫做出快速響應(yīng),同時在蘋果中過量表達(dá)可以明顯提高轉(zhuǎn)基因植株對干旱、低溫和鹽脅迫的耐受性[13,28]。油菜是的另一個同源基因,該基因可以對干旱、鹽和ABA處理作出快速響應(yīng),同時,啟動子活性可以受干旱、鹽和ABA處理的誘導(dǎo)[12]。在擬南芥中過量表達(dá)可以提高轉(zhuǎn)基因植株抗鹽能力,但沒有提高轉(zhuǎn)基因植株抗干旱的能力[12]。
VvCIPK10具有絲/蘇氨酸蛋白激酶結(jié)構(gòu)的典型特征,N端具有保守的激酶結(jié)構(gòu)域,是激活底物的關(guān)鍵功能域,C端具有一個NAF基序(也稱為FISL基序)和一個蛋白磷酸酶互作(protein phosphatase interaction,PPI)基序。CBL與CIPK的NAF基序結(jié)合可以解除其對CIPK活性的抑制,從而激發(fā)CIPK的自磷酸化和磷酸化活性,使CIPK-CBL復(fù)合體具有活性功能,進(jìn)而使復(fù)合體處于激活狀態(tài)[29-30]。PPI結(jié)合位點能夠與蛋白磷酸酶2C(PP2C)ABI的N端相互作用,如CIPK24和CIPK8能夠與ABI2相互作用,CIPK20與ABI1相互作用[4]。為分析VvCIPK10的激酶特性,筆者在大腸桿菌中表達(dá)了MBP-VvCIPK10融合蛋白,純化后進(jìn)行了自磷酸化分析,結(jié)果顯示VvCIPK10的自磷酸化依賴于Mn2+,但不依賴于Ca2+和Mg2+,同時EDTA可以抑制VvCIPK10依賴于Mn2+的自磷酸化活性。亞細(xì)胞定位結(jié)果顯示VvCIPK10主要定位在細(xì)胞核、細(xì)胞膜和細(xì)胞質(zhì)中,這與CIPK在細(xì)胞中的定位特性是一致的。體外激酶活性和亞細(xì)胞定位試驗表明VvCIPK10是一個典型的絲/蘇氨酸蛋白激酶。
在電子克隆的過程中發(fā)現(xiàn),與高度同源的6條EST序列均是受非生物脅迫誘導(dǎo)的。用干旱、低溫和鹽脅迫逆境處理葡萄幼苗后,的表達(dá)都呈現(xiàn)誘導(dǎo)表達(dá)模式。不同逆境處理的表達(dá)模式略有不同,其中干旱脅迫對的表達(dá)影響最為明顯,說明有可能主要參與抗旱反應(yīng)。小麥的表達(dá)受鹽、低溫和干旱脅迫的誘導(dǎo),其中受鹽脅迫表達(dá)變化更明顯,在煙草中過量表達(dá)導(dǎo)致轉(zhuǎn)基因植株抗鹽脅迫能力提高[11]。通過轉(zhuǎn)基因試驗分析的耐脅迫能力以及如何響應(yīng)逆境有待進(jìn)一步研究。
葡萄VvCIPK10的自磷酸化酶活性依賴于Mn2+,但不依賴于于Mg2+和Ca2+。VvCIPK10定位在細(xì)胞核、細(xì)胞膜和細(xì)胞質(zhì)。在葡萄各個組織中均有表達(dá),主要在葡萄根和葉片中大量表達(dá)。在干旱、低溫和鹽脅迫處理后,葡萄呈現(xiàn)受誘導(dǎo)表達(dá)模式。研究結(jié)果為進(jìn)一步研究參與逆境脅迫的分子功能,以及為探討葡萄抗逆分子機制提供了參考。
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(責(zé)任編輯 趙伶俐)
Characteristics and Expression of Calmodulin Like B Subunit Interaction Protein VvCIPK10 in Grapevine
YU Yi-he, LI Xiu-zhen, GUO Da-long, ZHANG Hui-ling, YANG Ying-jun, LI Xue-qiang, ZHANG Guo-hai
(College of Forestry, Henan University of Science and Technology, Luoyang 471003, Henan)
【Objective】The objective of this study is to clone serine/threonine protein kinaseinvolved in abiotic stress, and investigate the molecular mechanism of grapevine stress resistance. 【Method】The sequences ofwere obtained by electronic cloning technology, and the specific primers were designed to perform RT-PCR reaction. Open reading frame and conserved structure domain ofwere analyzed. The prokaryotic expression vector was constructed and transformed into the expression cells, and the recombinant bacteria were induced by IPTG. The expression products were collected and the protein sample was prepared. The protein samples were analyzed by SDS-PAGE electrophoresis, and the soluble characteristics of the fusion protein were analyzed. The fusion protein was induced by IPTG. The cells were collected and broken by using ultrasonic. The MBP-VvCIPK10 fusion protein was purified by maltose binding protein purification column and analyzed by SDS-PAGE. The purified fusion protein was incubated withself-phosphorylation buffer solution. After SDS-PAGE electrophoresis, the phosphor screen was performed and the phosphorylation reaction was detected. The recombinant transient expression vector pBI221-GFP/VvCIPK10 was constructed. The recombinant expression vector pBI221-GFP/VvCIPK10 was transformed into protoplasts by PEG mediated transient transformation. The recombinant expression vector pBI221-GFP/VvCIPK10 was transformed into onion epidermal cells by gene gun mediated transformation, and the fluorescence signal was detected by laser scanning confocal microscope after 16 h of culture. The relatively consistent and robust grape plants were selected, samples were taken at different times after drought, low temperature and salt stress treatments, at the same time, different tissue samples of grapes were taken in the field, with a kit to extract total RNA. After reverse transcription, expression ofwas detected by real-time quantitative PCR. 【Result】The full-length of1 357 bp, 5′ end of non-coding region is 30 bp, 3′ end of non-coding region is 156 bp, the open reading frame is 1 171 bp.open reading frame encoded 436 amino acids, the theoretical isoelectric point is 8.59, molecular weight is 48.7 kDa. Conserved domain prediction analysis showed that the protein has a kinase domain in 5′ terminal, a PPI domain and a NAF domain in 3′ terminal. BLSATP analysis showed VvCIPK10 consistency with peach CIPK (XP_007205151) is highest (74%). Recombinant expression vector pMAL-C5X/VvCIPK10 transformation in, expressed the molecular weight of fusion protein is consistent with the predicted molecular weight (43 kDa+48.7 kDa). MBP-VvCIPK10 fusion protein was purified by column. VvCIPK10 autophosphorylation activity was dependent on Mn2+but not dependent on Mg2+and Ca2+, and EDTA could inhibit the autophosphorylation activity of the VvCIPK10. Subcellular localization showed VvCIPK10 in the nucleus, cell membrane and cytoplasm. VvCIPK10 expressed in various tissues of grapevine. VvCIPK10 transcripts mainly accumulated in grapevine roots and leaves, but showed low expression levels in grapevine stem, inflorescence, fruit and tendril. After drought, low temperature and salt stress treatments,showed the induced expression model. The expression ofreached peak value at 6 h after low temperature stress, and reached the peak at 2 h after drought and salt stresses. 【Conclusion】It was concluded that grapevine VvCIPK10 as a serine threonine protein kinase is able to respond to drought, low temperature and salt stress, suggesting thatplays an important role in resistance to abiotic stress.
grapevine; calmodulin like B subunit; serine threonine protein kinase;; expression analysis
2016-04-15;接受日期:2016-09-12
國家自然科學(xué)基金(U1504321,31372026)、河南省教育廳科學(xué)技術(shù)研究重點項目(14A210018)、河南省教育廳科技攻關(guān)項目(17020005)、河南省科技創(chuàng)新人才計劃(164100510006)、河南省高??萍紕?chuàng)新人才支持計劃(13HASTIT004)、河南科技大學(xué)創(chuàng)新團(tuán)隊項目(2015TTD003)
余義和,Tel:0379-64282345;E-mail:yuyihe2008@163.com。通信作者張國海,Tel:0379-64283362;E-mail:guohaizhang@126.com