高華利 王黎明 柴軍琳 董普輝 王春平 李興鋒
小麥籽粒品質性狀基因功能標記的開發及應用
高華利1王黎明1柴軍琳1董普輝1王春平1李興鋒2
(河南科技大學農學院1,洛陽 471023)
(山東農業大學農學院2,泰安 271018)
小麥籽粒加工品質是一個綜合性狀,并與高、低分子質量亞基、多酚氧化酶活性、脂肪氧化酶活性、黃色素含量、籽粒硬度、淀粉特性和1BL/1RS易位等多個性狀密切相關。本研究主要就這些小麥品質相關性狀基因的功能標記開發及其在分子育種應用的研究進展進行了綜述,并對其當前存在的問題和未來發展方向進行了討論。
小麥 品質性狀基因 功能標記
隨著結構基因組學及功能基因組學的快速發展,基因功能標記的開發與應用逐漸成為小麥等重要農作物分子育種的重要方向。利用功能標記對小麥籽粒品質相關性狀進行檢測大大提高了其在分子標記輔助育種上的選擇效率;同時為育種過程中親本的選擇和確定材料的利用價值提供了重要信息[1]。因此,小麥品質相關性狀的功能標記在育種工作中具有較大應用價值,特別是在小麥品質改良方面受到了廣泛應用。
小麥面制品的加工品質與高分子質量谷蛋白亞基(High-molecular-weight glutenin subunit,HMW -GS)、低分子質量谷蛋白亞基(Low-molecularweight glutenin subunit,LMW - GS)、多酚氧化酶(Polyphenol oxidase,PPO)活性、脂肪氧化酶(Lipoxygenase,LOX)活性、黃色素含量(Yellow pigment content,YPC)、籽粒硬度、淀粉特性及1BL/1RS 易位等高度相關。據不完全統計,小麥籽粒加工品質相關性狀的21個位點的62個等位基因已經克隆,已開發并驗證了63個功能標記。
HWM-GS和LWM-GS是小麥籽粒中重要的貯藏蛋白,影響小麥面團黏彈性和延展性,對小麥面團品質起重要的作用,分別由位于第一同源群上的位點Glu-1和Glu-3所編碼。研究表明[2-3],HMW-GS位點存有許多變異,Glu-A1位點編碼的亞基為HMW-GS1、2*和Null;Glu-B1位點編碼的亞基為HMW -GS7、7 +8、7 +9、6 +8、20、13 +16、13 +19、14+15、17+18、21和22等;Glu-D1位點編碼的亞基為HMW -GS2+12、5+10,3+12、4+12、2+10等。一般具有亞基5+10的品種品質較好,適于小麥優質育種。具有亞基組合GluA3f、GluB3b,GluA3d、GluB3g和GluA3c、GluB3g的品種,品質性狀明顯較優,適于小麥優質育種。根據對上述位點核苷酸序列開發功能標記[4-9],可用來有效鑒定小麥品種中HWM-GS和LWM-GS的等位基因。
根據LMW麥谷蛋白基因的DNA多態性,Glu-A3等位基因的功能標記已被開發[10],然而,由于Glu-D3位點等位基因間的變異非常小,所以還沒有開發相應的功能標記[11]。與Glu-A3和Glu-B3位點相比,Glu-D3對面團品質的影響相對較小[12]。HMW -GSDx5、Bx7、Bx7oe、By8、By9、By16 等亞基的功能標記也已開發,并能夠有效地用于檢測小麥品種和品系[13-15],表明這些標記準確、穩定,可用于小麥分子標記輔助育種。
小麥籽粒中PPO活性與面條等面制品在制作過程中發生的褐變密切相關,是嚴重影響面制品的商品價值和外觀質量的重要性狀。研究發現,在低PPO活性品種中,Ppo-A1上的功能標記PPO18和PPO33的PCR擴增產物分別為876 bp和481 bp的片段,而標記PPO16和PPO29可以區分與高、低PPO活性緊密相關的Ppo - D1b 和Ppo - D1a[16-17]。利用這些功能標記分別在中國高/低PPO活性的小麥品系、311份中國小麥品種和高代品系、57份印度小麥品種以及273份CIMMYT小麥品系的鑒定中得到廣泛應用[12,18-19]。陳杰[20]利用STS 標記PPO18,PPO16 和PP029[16,21]檢測了參試小麥品種在Ppo -A1和Ppo-D1位點基因的等位變異。因此,利用開發的PPO活性相關的功能標記,可以用于低PPO活性的小麥種質的篩選和高代品系的鑒定。
LOX活性對小麥加工品質和色澤起重要作用,其由多基因控制。根據2個等位基因TaLox-B1a和TaLox-B1b在第三外顯子上一個SNP的差異,一對互補的顯性功能標記LOX16和LOX18已被開發,這2個標記在高、低LOX活性品種中分別擴增出489 bp 和791 bp 片段[22]。吳萍[23]根據小麥LOX1基因本身的序列信息開發了一個操作方便、可靠性強的新功能標記LOX1-wp01。
目前,LOX功能標記多用于不同地區小麥LOX活性等位變異的分布分析。研究發現,LOX高活性TaLox-B1a基因在新疆冬小麥品種(系)的分布頻率遠遠高于春小麥,在陜西小麥品種(系)中,低LOX活性等位變異品種的比例則明顯高于高LOX活性品種,甘肅冬小麥品種高LOX活性等位變異TaLox-B1a 的分布頻率高于春小麥[24-26]。
小麥籽粒黃色素含量主要影響面粉加工品質及籽粒外觀顏色。影響小麥黃色素含量的關鍵基因—八氫番茄紅素合成酶(PSY)基因由多個基因位點控制,但位于7A、7B、7D同源群上檢測到的QTL效應值最大[27]?;虻任蛔儺怭sy-B1a、Psy -B1c、Psy -B1e、Psy-B1f等與高黃色素含量相關,而Psy-B1b、Psy-B1g等與低黃色素含量相關[28-29],有利于小麥優質育種。He等[28-29]開發出了7A 染色體上基因Psy-A1功能標記YP7A、YP7A-2以及7B染色體上Psy-B1基因YP7B -1、YP7B -2、YP7B -3、YP7B -4。
研究發現,功能標記YP7B-1在Psy-B1f材料中擴增的151 bp片段與高黃色素含量相關,而在Psy-B1g材料中擴增的153 bp片段與低黃色素含量相關[30]。因此,可以利用黃色素含量相關的功能標記對小麥八氫番茄紅素合成酶基因的變異類型進行篩選。
籽粒硬度不僅決定磨粉能耗、潤麥加水量和出粉率,而且與面粉色澤和灰分含量有關,其主要由位于小麥5DS染色體上編碼Puroindoline a和Puroindoline b蛋白的Pina-D1和Pinb-D1基因決定。研究表明,基因Pina或Pinb發生突變以及基因Pina缺失均會導致小麥胚乳質地變硬[31-32]。STS功能標記Pina-N1、Pina-N2、Pina-N3和Pina-N4等可以對puroindoline基因變異類型Pina-D1b、Pina-D1r、Pina -D1s和Pina - D1u 進行鑒定[33-34]。在小麥育種中,與較好的磨粉和加工品質相關的Pinb-D1b等位基因的功能標記使用比較廣泛[35-36]。研究共發現5種硬度基因組合類型,分別為野生型、Pina-D1b、Pinb-D1b、Pinb-D1c、Pinb-D1p,其中野生型的比例最高(51.22%)[37]。另外,硬度相關功能標記還有效用于不同地區小麥材料的硬度類型的鑒定。研究表明,青海小麥材料以硬質類型為主,比例為47.0%,河南省小麥新品種(系)以硬質麥為主,比例為64.1%[38-39]。
小麥直鏈淀粉含量對面條品質有重要作用,其中顆粒結合淀粉合成酶(Granule-bound starch synthase,GBSSⅠ)是一個胚乳中直鏈淀粉合成的關鍵酶,被Wx-A1、Wx-B1和Wx-D1等3個基因位點編碼,分別位于小麥7AS、4AL、7DS染色體上;GBSSI表達產物為Waxy(Wx)蛋白,小麥籽粒中不含有Wx-A1、Wx-B1和Wx-D1所編碼的Wx蛋白,分別被稱之為Wx-A1缺失型、Wx-B1缺失型和Wx-D1缺失型,常常表現為具有較低的直鏈淀粉水平。劉迎春等[40]根據小麥Waxy基因序列建立了分別專一檢測Wx-A1位點和Wx-D1位點的STS功能標記MAG264 和MAG269。Nakamura 等[41-42]開發了鑒定Wx-B1等位基因的功能標記。研究發現,Wx-B1蛋白缺失影響直鏈淀粉含量和淀粉糊化特性,Wx-A1、Wx-B1和Wx-D1三個等位基因缺失對Wx蛋白的不同作用,首先為Wx-B1蛋白的缺失型,其次是Wx-D1缺失,最后是Wx-A1的缺失[43]。由于Wx-A1和Wx-D1基因缺失的情況極少出現在小麥品種中,因此它們的功能標記不如Wx-B1缺失等位基因的使用廣泛。
小麥1BL/黑麥1RS易位的SCAR標記AF1/AF4由Francis等[44]開發,利用該標記可以對小麥品種和優良新品系進行基因等位變異的檢測[45]。前人以不同來源的小麥和黑麥為材料,開發出了1BL/1RS特異功能標記ω -Sec-P1/P2、ω -Sec-P3/P4、SECA2/SECA3、H20 等,這些標記均能用于小麥和黑麥相關材料的鑒定[46-47]。
小麥籽粒品質與HMW-GS、PPO活性、籽粒硬度、淀粉特性等多個性狀密切相關,因此在注重單一質量性狀改良基礎上,更應該重視多個優良性狀的聚合與同步改良,以提高小麥籽粒的綜合加工品質;除了在對小麥單一品質性狀功能標記利用外,應該注重多個品質相關性狀功能標記的綜合利用及其不同性狀之間的相關性分析,并加強多個標記反應體系研究,以便于更好地提高育種選擇效率。中國農業科學院作物科學研究所利用多個與品質性狀相關的功能標記進行輔助選擇,已經培育出20多個小麥品系參加區域試驗。總之,在育種實踐中,應該注重分子標記研發單位與育種主體等多單位聯合攻關,分子生物學家與育種家等專家通力合作,綜合利用分子標記技術與基因分型技術、高通量基因組學分析與常規田間單株選擇與鑒定等多學科知識,并將其盡快轉化成切實可行、經濟、高效的小麥育種技術。
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Development and Application of Functional Markers Linked to Wheat Grain Quality Traits Genes
Gao Huali1Wang Liming1Chai Junlin1Dong Puhui1Wang Chunping1Li Xingfeng2
(College of Agronomy,Henan University of Science and Technology1,Luoyang 471003)
(College of Agronomy,Shandong Agricultural University2,Taian 271018)
Wheat grain processing quality was a complicated trait which was related to many specific traits in-cluding high molecular weight glutenin subunits(HMW - GS)and low molecular weight glutenin subunits(LMW -GS),the activity of polyphenol oxidase(PPO),the activity of lipoxygenase(LOX),yellow pigment content(YPC),grain hardness,starch properties,1BL/1RS translocation,etc.In this article,the development of functional markers linked to wheat grain processing quality traits-related genes and their applications in wheat were overviewed.At the same time,the existing problems and prospects were discussed.
wheat,quality traits - related genes,functional marker
S512.1;S331
A
1003-0174(2016)08-0152-06
國家自然科學基金(U1304318,U1304320),作物生物學國家重點實驗室開放基金(2008KF01)
2014-12-26
高華利,女,1990年出生,碩士,小麥種質創新與分子育種
王黎明,男,1976年出生,博士,副教授,生物技術與種質創新及新品種選育