甘藍(lán)型油菜開(kāi)花相關(guān)基因的鑒定及進(jìn)化與表達(dá)分析

王艷花 謝 玲 楊 博 曹艷茹 李加納,*

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甘藍(lán)型油菜開(kāi)花相關(guān)基因的鑒定及進(jìn)化與表達(dá)分析

王艷花1,2謝 玲1,2楊 博1,2曹艷茹1,2李加納1,2,*

1西南大學(xué)農(nóng)學(xué)與生物科技學(xué)院 / 油菜工程研究中心, 重慶 400715;2西南大學(xué)現(xiàn)代農(nóng)業(yè)科學(xué)研究院, 重慶 400715

開(kāi)花是開(kāi)花植物繁衍后代的前提, 控制開(kāi)花時(shí)間對(duì)農(nóng)作物獲得高產(chǎn)穩(wěn)產(chǎn)具有重要影響。然而, 關(guān)于甘藍(lán)型油菜基因組水平上開(kāi)花相關(guān)基因的信息報(bào)道較少。本研究對(duì)甘藍(lán)型油菜開(kāi)花相關(guān)的基因進(jìn)行了鑒定、特征分析、進(jìn)化與表達(dá)模式分析。結(jié)果表明, 基因組水平上共鑒定到甘藍(lán)型油菜1173個(gè)開(kāi)花相關(guān)基因, 這些基因分為9類(lèi), 且不均勻地分布在染色體上; 與白菜(AA, 2=20)和甘藍(lán)(CC, 2=18)相比, 甘藍(lán)型油菜(AACC, 2=38)經(jīng)過(guò)自然雜交和染色體加倍后, 使開(kāi)花相關(guān)基因的數(shù)目顯著擴(kuò)增; 選擇壓力分析表明, 糖代謝信號(hào)途徑的基因比自發(fā)途徑的開(kāi)花相關(guān)基因受到的選擇壓力更大; 仍有一些開(kāi)花相關(guān)基因在擬南芥和油菜基因組內(nèi)非常保守。甘藍(lán)型油菜基因數(shù)目的擴(kuò)增和功能分化導(dǎo)致其開(kāi)花調(diào)控機(jī)制更加復(fù)雜, 本研究為油菜開(kāi)花途徑提供更多的信息, 也為闡明擬南芥和油菜開(kāi)花基因的進(jìn)化關(guān)系指明了方向。

甘藍(lán)型油菜; 開(kāi)花基因; 進(jìn)化; 調(diào)控途徑; 表達(dá)分析

開(kāi)花是開(kāi)花植物成功繁衍的前提。對(duì)于農(nóng)作物而言, 開(kāi)花時(shí)間適當(dāng)是作物獲得高產(chǎn)和優(yōu)質(zhì)的重要條件, 而且開(kāi)花時(shí)間受環(huán)境影響比較大, 因此, 開(kāi)花時(shí)間是一項(xiàng)重要的農(nóng)藝指標(biāo), 對(duì)作物有性繁殖和高產(chǎn)具有重要影響。目前, 大多數(shù)影響作物開(kāi)花時(shí)間的遺傳組成和環(huán)境因子的信息都是從擬南芥研究中獲得的[1]。開(kāi)花時(shí)間受外界和自身信號(hào)調(diào)控[2], 受環(huán)境影響的光周期途徑和環(huán)境溫度途徑, 受內(nèi)部信號(hào)調(diào)控的自主開(kāi)花途徑、赤霉素途徑和衰老途徑的顯著影響[1]。在擬南芥中有超過(guò)300個(gè)開(kāi)花相關(guān)基因被鑒定(Flowering Interactive Database)[3]。這些基因參與自發(fā)途徑、光周期、赤霉素、春化和內(nèi)在因素(包括衰老和糖信號(hào))途徑五大開(kāi)花通路[4]。盡管不同基因參與不同的通路, 但不同通路均受到()、()、()、()等幾個(gè)關(guān)鍵基因的協(xié)同調(diào)控[5]。然而, 僅有很少的開(kāi)花基因在重要作物中得到鑒定?；蚪M序列的釋放和新的計(jì)算方法的開(kāi)發(fā)為在基因組水平上鑒定開(kāi)花相關(guān)基因提供了極大便利, 比如在蘿卜和小麥中分別鑒定到254個(gè)和900個(gè)開(kāi)花相關(guān)基因[6]。

油菜是全世界廣泛種植的油料作物之一。開(kāi)花時(shí)間在不同油菜品種之間具有非常廣泛的變異。前人利用QTL手段研究油菜開(kāi)花時(shí)間, 但只有少數(shù)的基因如等得到鑒定或克隆[7-8]。與QTL定位、轉(zhuǎn)錄組測(cè)序和實(shí)驗(yàn)驗(yàn)證方法相比, 比較基因組學(xué)成為非常方便的手段來(lái)篩選開(kāi)花候選基因, 特別在非模式作物研究中[6,9], 已經(jīng)為重要性狀進(jìn)一步的功能驗(yàn)證提供非常重要的信息。目前, 在油菜基因組水平上還沒(méi)有展開(kāi)開(kāi)花相關(guān)基因的鑒定工作。本研究在基因組水平上鑒定了油菜開(kāi)花相關(guān)基因, 并揭示了這些基因的進(jìn)化和表達(dá)模式, 為油菜開(kāi)花研究提供更多的候選基因, 為進(jìn)一步揭示油菜開(kāi)花機(jī)理奠定基礎(chǔ)。

1 材料與方法

1.1 甘藍(lán)型油菜、白菜和甘藍(lán)開(kāi)花相關(guān)基因的篩選

從網(wǎng)站TAIR10 (http://www.arabidopsis.org/)下載擬南芥開(kāi)花基因的蛋白序列, 從網(wǎng)站BRAD (http:// brassicadb.org/brad/)下載甘藍(lán)、白菜和甘藍(lán)型油菜的基因注釋信息。利用擬南芥開(kāi)花基因的蛋白序列在BRAD網(wǎng)站上進(jìn)行Blastp分析, 篩選甘藍(lán)型油菜、白菜和甘藍(lán)開(kāi)花相關(guān)基因, 篩選標(biāo)準(zhǔn)為E值 <1e–20、相似度>60%、覆蓋率>75%以及匹配長(zhǎng)度>70氨基酸殘基。

1.2 甘藍(lán)型油菜開(kāi)花相關(guān)基因的染色體分布

從甘藍(lán)型油菜基因組網(wǎng)站(http://www.genoscope. cns.fr/brassicanapus/)下載, 并利用軟件Mapchart (https://www.wur.nl/en/show/Mapchart.htm)展示甘藍(lán)型油菜開(kāi)花相關(guān)基因的物理位置信息。

1.3 甘藍(lán)型油菜開(kāi)花相關(guān)基因的選擇壓力分析

為分析開(kāi)花相關(guān)基因的選擇壓力, 利用軟件PAML計(jì)算甘藍(lán)型油菜與擬南芥開(kāi)花相關(guān)基因?qū)Φ姆峭x替換率(Ka)與同義替換率(Ks)[10]。當(dāng)Ka/Ks比值大于1, 等于1或小于1時(shí), 分別表示基因受到正向、中性和純化選擇[11]。

1.4 甘藍(lán)型油菜開(kāi)花相關(guān)基因的表達(dá)分析

利用本課題組前期完成的轉(zhuǎn)錄組數(shù)據(jù)(NCBI注冊(cè)號(hào)為PRJNA358784)分析甘藍(lán)型油菜開(kāi)花相關(guān)基因的組織表達(dá)情況。利用軟件Cufflinks[12]和TopHat2[13]計(jì)算基因的表達(dá)量FPKM (fragments per kilobase of exon per million mapped reads)。利用軟件MeV 4.9.0 (http://en.bio-soft.net/chip/MeV.html)展示表達(dá)熱圖。

2 結(jié)果與分析

2.1 甘藍(lán)型油菜開(kāi)花相關(guān)基因的鑒定與染色體分布

利用擬南芥306個(gè)開(kāi)花基因[3],本研究篩選到1173個(gè)甘藍(lán)型油菜開(kāi)花相關(guān)基因(附表1),在甘藍(lán)型油菜基因組內(nèi)可以找到超過(guò)89.5%的擬南芥開(kāi)花基因同源基因(附表2)。大部分的油菜開(kāi)花相關(guān)基因?qū)儆诠庵芷?、生物鐘和光信?hào)途徑(圖1)。

根據(jù)基因的位置信息,1045個(gè)開(kāi)花相關(guān)基因被定位在19條染色體上, 剩余128個(gè)基因被定位在“unanchored scaffolds”上。這些基因在油菜基因組內(nèi)分布是非常不均勻的, 在C01上有101個(gè)基因,A09上75個(gè),A03上74個(gè),在A08上最少,只有33個(gè)基因(圖2)。

圖1 甘藍(lán)型油菜開(kāi)花相關(guān)基因鑒定與分類(lèi)

Ag: 衰老途徑; At: 環(huán)境溫度; Au: 自發(fā)途徑; Cp: 光周期途徑; Fd: 花器官發(fā)育及頂端分生組織響應(yīng)途徑; Ft: 開(kāi)花時(shí)間調(diào)控者; Ho: 激素途徑; Su: 糖信號(hào); Ve: 春化。

Ag: aging pathway; At: ambient temperature; Au: autonomous pathway; Cp: clock and photoperiod, pathway; Fd: flower development and apical meristem response pathway; Ft: flowering time integrator; Ho: hormones pathway; Su: sugar signal; Ve: vernalization.

2.2 擬南芥、白菜、甘藍(lán)和甘藍(lán)型油菜開(kāi)花相關(guān)基因的比較分析

在白菜和甘藍(lán)基因組內(nèi), 共鑒定出549個(gè)和561個(gè)開(kāi)花相關(guān)基因(圖3和附表3)。根據(jù)擬南芥開(kāi)花基因的分類(lèi)信息[3], 甘藍(lán)型油菜、白菜和甘藍(lán)的開(kāi)花同源基因可參與9大類(lèi), 即衰老途徑、溫度、自發(fā)途徑、光周期、花器官發(fā)育、開(kāi)花調(diào)控因子、激素、糖及春化途徑。而且, 有些基因可能會(huì)參與多個(gè)途徑, 如和同時(shí)參與花器官發(fā)育以及開(kāi)花調(diào)控因子。大部分基因?qū)儆诠庵芷诤妥园l(fā)途徑, 溫度途徑基因在4個(gè)物種中均是最少的。

2.3 甘藍(lán)型油菜開(kāi)花相關(guān)基因的關(guān)鍵通路和基因家族分析

2.3.1 光周期途徑 光周期是顯著影響植物開(kāi)花時(shí)間的外界環(huán)境因子[14]。在該途徑中, 利用103個(gè)擬南芥開(kāi)花基因, 共鑒定出401個(gè)甘藍(lán)型油菜開(kāi)花相關(guān)同源基因(圖1和附表1)。作為核心調(diào)控因子, CONSTANS(CO)整合外界環(huán)境因素如日照長(zhǎng)度與內(nèi)在的生物鐘過(guò)程來(lái)顯著調(diào)節(jié)開(kāi)花時(shí)間[15]。在甘藍(lán)型油菜中共篩選出4個(gè)基因, 同時(shí)篩選出參與生物鐘過(guò)程的關(guān)鍵基因如、和[1,16-18]。ZTL、FKF1和LKP2均屬于F-box蛋白[19], 但是在甘藍(lán)型油菜基因組內(nèi)沒(méi)有篩選到和的同源基因, 而卻有6個(gè)同源基因。在白菜和甘藍(lán)基因組內(nèi)同樣沒(méi)有和基因, 表明和的基因丟失以及的三倍化事件同樣發(fā)生在共同祖先白菜和甘藍(lán)基因組內(nèi)[20]。在甘藍(lán)型油菜中同樣篩選出光信號(hào)途徑的關(guān)鍵因子如和[1]。

2.3.2 春化和自發(fā)途徑 許多植物都需要春化過(guò)程來(lái)誘導(dǎo)開(kāi)花。大量研究證明()基因和FLOWERING LOCUS C (FLC)基因在春化過(guò)程中起至關(guān)重要的作用[4]。作為開(kāi)花抑制因子, FLC被FRI正向調(diào)控[21]。在甘藍(lán)型油菜基因組內(nèi)有9個(gè)同源基因。同時(shí), 在甘藍(lán)和白菜基因組內(nèi)分別檢測(cè)到2個(gè)和1個(gè)同源基因, 沒(méi)有篩選到基因。而且, 很多春化響應(yīng)基因如、和也在甘藍(lán)、白菜和甘藍(lán)型油菜基因組內(nèi)被檢測(cè)到。與春化途徑相似, 自發(fā)途徑基因如()、()、、和通過(guò)抑制的表達(dá)來(lái)間接誘導(dǎo)開(kāi)花[22-23]。在甘藍(lán)型油菜基因組內(nèi), 有461個(gè)基因?qū)儆谧园l(fā)途徑。

(圖2)

圖3 不同開(kāi)花途徑基因在擬南芥、白菜、甘藍(lán)和甘藍(lán)型油菜基因組內(nèi)的數(shù)目

縮寫(xiě)同圖1。Abbreviation are the same as those given in Fig. 1.

2.3.3 頂端分生組織響應(yīng)途徑 開(kāi)花時(shí)間受到復(fù)雜的遺傳因子的調(diào)控, 這類(lèi)調(diào)控因子被稱(chēng)之為“調(diào)控者”基因, 可以整合內(nèi)外環(huán)境信號(hào)和不同途徑的信號(hào)[24-25]。在本研究中, 91個(gè)開(kāi)花相關(guān)基因被鑒定為“調(diào)控者”基因, 比如等。在甘藍(lán)型油菜基因組內(nèi)僅有1個(gè)同源基因。

2.3.4 赤霉素信號(hào)與代謝途徑 很多證據(jù)表明, 在短日照情況下, 赤霉素是開(kāi)花的必要條件, 但在長(zhǎng)日照條件下則不需要。截至目前, 在擬南芥中有28個(gè)基因參與赤霉素途徑, 這些基因主要分為赤霉素合成途徑基因如和[26]和信號(hào)傳導(dǎo)因子基因如和[27]。在甘藍(lán)型油菜基因組內(nèi), 除之外, 所有赤霉素相關(guān)基因都有同源基因。GAI屬于DELLA蛋白家族, 但另外一個(gè)DELLA蛋白家族成員在甘藍(lán)型油菜基因組內(nèi)卻有7個(gè)同源基因, 該基因抑制植物從苗期向花期的轉(zhuǎn)變[28]。

2.3.5 溫度途徑 溫度可以顯著影響開(kāi)花時(shí)間[29]。適當(dāng)高溫可以促進(jìn)開(kāi)花, 在擬南芥中已經(jīng)有響應(yīng)溫度的關(guān)鍵基因被鑒定, 如、和[1]。在甘藍(lán)型油菜中, 篩選到6個(gè)同源基因, 該基因在高溫環(huán)境中通過(guò)結(jié)合的啟動(dòng)子來(lái)誘導(dǎo)開(kāi)花[30]。作為MADS-box蛋白, SVP通過(guò)響應(yīng)外界溫度來(lái)調(diào)節(jié)開(kāi)花時(shí)間, 該蛋白通過(guò)結(jié)合在和的啟動(dòng)子區(qū)域來(lái)抑制開(kāi)花[31], 而EFM通過(guò)正調(diào)節(jié)SVP來(lái)參與調(diào)控開(kāi)花時(shí)間[32]。在甘藍(lán)型油菜中,和各有4個(gè)同源基因。

2.3.6 糖信號(hào)途徑 除了赤霉素, 糖也可以參與調(diào)節(jié)開(kāi)花時(shí)間[1]。特別指出的是, 蔗糖和海藻糖顯著影響開(kāi)花時(shí)間[33-34]。在甘藍(lán)型油菜中, 46個(gè)影響開(kāi)花的糖代謝相關(guān)的同源基因被鑒定。作為正向調(diào)控開(kāi)花因子, TREHALOSE-6-PHOSPHATE SYNTHASE 1 (TPS1)參與海藻糖合成, 不管長(zhǎng)日照還是短日照環(huán)境, 下調(diào)該基因都將導(dǎo)致開(kāi)花延后[35]。編碼鋅指類(lèi)轉(zhuǎn)錄因子, 通過(guò)調(diào)控糖的運(yùn)輸和代謝來(lái)促進(jìn)開(kāi)花[36]。

2.3.7 衰老途徑 在甘藍(lán)型油菜基因組內(nèi)共鑒定出43個(gè)影響開(kāi)花的衰老途徑同源基因。該途徑的關(guān)鍵基因包括(和)、和[1]。很多證據(jù)表明miRNAs參與開(kāi)花調(diào)控。其中和分別編碼miR156和miR172。隨著植物年齡增長(zhǎng), miR156表達(dá)量下調(diào), 但是miR172表達(dá)量升高。miR156和miR172分別通過(guò)調(diào)控靶基因和基因來(lái)調(diào)控開(kāi)花時(shí)間。作為開(kāi)花抑制因子, 不管長(zhǎng)日照還是短日照, 過(guò)表達(dá)SMZ都可以延遲開(kāi)花[37-38]。miR156的靶基因通過(guò)誘導(dǎo)miR172來(lái)間接促進(jìn)開(kāi)花[39]。另外, HXK1參與果糖和葡萄糖的磷酸化, 其通過(guò)抑制miR156間接促進(jìn)開(kāi)花, 突變體在長(zhǎng)日照環(huán)境中推遲開(kāi)花時(shí)間[40]。

2.4 開(kāi)花相關(guān)基因的選擇壓力分析

同源基因?qū)Φ腒a/Ks比值被用來(lái)當(dāng)作選擇壓力的指標(biāo)。對(duì)于開(kāi)花相關(guān)基因在擬南芥和油菜之間的垂直同源基因?qū)Φ倪x擇壓力, 計(jì)算表明, 各開(kāi)花相關(guān)基因通路的Ka/Ks比值范圍為0.18~0.46 (圖4和附表4), 表明開(kāi)花相關(guān)基因受到純化選擇壓力。

圖4 甘藍(lán)型油菜不同開(kāi)花途徑基因的選擇壓力分析

縮寫(xiě)同圖1。Abbreviations are the same as those given in Fig. 1.

2.5 甘藍(lán)型油菜開(kāi)花相關(guān)基因的表達(dá)分析

本研究利用課題組前期完成的以“中雙11”為材料獲得的各時(shí)期各組織表達(dá)的轉(zhuǎn)錄組數(shù)據(jù)(NCBI注冊(cè)號(hào)為PRJNA358784)分析甘藍(lán)型油菜開(kāi)花基因的表達(dá)特征。由圖5可知, 非功能化、新功能化或次功能化現(xiàn)象在重復(fù)基因?qū)?nèi)出現(xiàn), 盡管多數(shù)基因?qū)哂邢嗨频谋磉_(dá)模式, 但有些具有新的功能。

3 討論

白菜、甘藍(lán)和甘藍(lán)型油菜基因組數(shù)據(jù)的釋放為研究重要農(nóng)藝性狀的基因及功能提供了極大的便利[41-43]。雖然很多基因在擬南芥中都已經(jīng)研究的很透徹, 但其同源基因在以上3種近源物種中的功能尚不明確。為補(bǔ)充這些信息, 本研究利用擬南芥開(kāi)花相關(guān)基因, 通過(guò)同源比對(duì)的方法篩選到1173個(gè)甘藍(lán)型油菜、561個(gè)甘藍(lán)和549個(gè)白菜開(kāi)花相關(guān)同源基因?？紤]到白菜、甘藍(lán)和甘藍(lán)型油菜的基因組大小, 甘藍(lán)型油菜基因組內(nèi)的開(kāi)花相關(guān)基因的數(shù)目比其在白菜和甘藍(lán)基因組內(nèi)數(shù)量的總和還要多[41,43]。甘藍(lán)型油菜基因組內(nèi)的開(kāi)花相關(guān)基因數(shù)目是其在擬南芥基因組內(nèi)的3.8倍, 有些同源基因數(shù)目超過(guò)6個(gè), 有些則低于3個(gè), 表明同源基因內(nèi)發(fā)生了丟失、重組、功能保留和分化。然而, 這并不影響甘藍(lán)型油菜主要的開(kāi)花途徑, 因?yàn)橛筒送瑯涌梢哉檄h(huán)境內(nèi)外的信號(hào)來(lái)調(diào)控開(kāi)花時(shí)間。

在甘藍(lán)型油菜中篩選到一些光周期途徑的關(guān)鍵調(diào)控因子基因, 如、和。且在甘藍(lán)型油菜基因組內(nèi)篩選到2個(gè)同源基因, 這2個(gè)成員在各組織器官中的表達(dá)量均較高。在甘藍(lán)型油菜中有7個(gè)同源基因, 且該基因在擬南芥中已經(jīng)得到驗(yàn)證[44], 其中4個(gè)成員表達(dá)量較高, 而其余3個(gè)成員幾乎不表達(dá), 可能發(fā)生非功能化。在甘藍(lán)型油菜中篩選得到的6個(gè)同源基因在所有檢測(cè)的組織中表達(dá)量均較高, 可能誘導(dǎo)的表達(dá)[45]。生物鐘途徑的關(guān)鍵調(diào)控因子的2個(gè)同源基因也同樣具有較高的表達(dá)量[17]。在甘藍(lán)型油菜中有4個(gè)同源基因, 其中2個(gè)表達(dá)量較高, 而其余2個(gè)幾乎不表達(dá)。GI和CO的存在表明在甘藍(lán)型油菜中GI/CO調(diào)控開(kāi)花時(shí)間的方式是非常保守的。相比其他途徑基因, 光周期途徑的基因的Ka/Ks比值的變異范圍更廣。

作為開(kāi)花關(guān)鍵調(diào)控因子, 在甘藍(lán)型油菜基因組內(nèi)分別檢測(cè)到9個(gè)、4個(gè)、6個(gè)、3個(gè)、4個(gè)和5個(gè)。在自發(fā)和春化途徑中, FLC是關(guān)鍵的調(diào)控因子, 其通過(guò)與FRI互作來(lái)抑制開(kāi)花過(guò)程[46]。盡管在甘藍(lán)型油菜基因組內(nèi)有9個(gè)同源基因, 但其表達(dá)量都很低, 可能跟取材時(shí)間有關(guān)。在甘藍(lán)型油菜中鑒定得到自發(fā)途徑和長(zhǎng)日照條件下起重要作用的4個(gè)同源基因[47], 但只有1個(gè)成員表達(dá)量較高。整合光周期、春化和自發(fā)途徑的關(guān)鍵調(diào)控因子[48]在甘藍(lán)型油菜中有6個(gè)同源基因, 其中4個(gè)表達(dá)量較高。編碼一個(gè)促進(jìn)早開(kāi)花的轉(zhuǎn)錄因子, 該轉(zhuǎn)錄因子與APETALA1 (AP1)協(xié)同作用[49], 在甘藍(lán)型油菜中有4個(gè)成員, 其中2個(gè)在主序頂端中高表達(dá), 5個(gè)同源基因, 均在花蕾、花萼、萼片、花瓣和主序頂端中高表達(dá)?？傊? 幾個(gè)開(kāi)花關(guān)鍵調(diào)控因子可以通過(guò)整合不同途徑信號(hào)來(lái)調(diào)控開(kāi)花時(shí)間, 表明開(kāi)花調(diào)控過(guò)程在擬南芥和油菜中是非常保守的。

圖5 甘藍(lán)型油菜開(kāi)花相關(guān)基因的組織表達(dá)分析

縮寫(xiě)同圖1。Abbreviations are the same as those given in Fig. 1.

4 結(jié)論

在甘藍(lán)型油菜中鑒定出1173個(gè)開(kāi)花相關(guān)基因, 并分為9大類(lèi)。開(kāi)花調(diào)控機(jī)制在擬南芥和油菜之間是非常保守的, 保留了主要的調(diào)控通路和調(diào)節(jié)因子。光周期途徑比其他途徑的選擇壓力變異更大。這為甘藍(lán)型油菜開(kāi)花調(diào)控機(jī)制提供更多的信息, 為育種家培育新品種提供基礎(chǔ)。

附表 請(qǐng)見(jiàn)網(wǎng)絡(luò)版: 1) 本刊網(wǎng)站http://zwxb.china-crops.org/; 2) 中國(guó)知網(wǎng)http://www.cnki.net/; 3) 萬(wàn)方數(shù)據(jù)http://c.wanfangdata.com.cn/Periodical-zuowxb. aspx。

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Flowering genes in oilseed rape: identification, characterization, evolutionary and expression analysis

WANG Yan-Hua1,2, XIE Ling1,2, YANG Bo1,2, CAO Yan-Ru1,2, and LI Jia-Na1,2,*

1College of Agronomy and Biotechnology, Southwest University/ Chongqing Engineering Research Center for Rapeseed, Chongqing 400715, China;2Academy of Agricultural Sciences, Southwest University, Chongqing 400715, China

Flowering is a prerequisite for successful sexual reproduction. Controlling of flowering time is important for crop production in different geographical regions. However, few information regarding flowering genes or their evolution at genome-wide level inhas been reported. In this study, identification, characterization, evolutionary and expression analysis of flowering genes in oilseed rape were performed. In total, 1173 flowering-related genes classified into nine types and distributed unevenly on the chromosomes were identified at the genome level of. Compared with(AA, 2= 20) and(CC, 2= 18),(AACC, 2= 38) showed significantly enlarge number of flowering-related genes due to natural hybridization and chromosome doubling. Selective pressure analysis showed that the autonomous pathway genes had less selectionpressure than the genes involved in sugar metabolic pathway, suggesting that some key flowering-related genes are relatively conserved betweenand. The present study provides more information on theflowering pathways and sheds light on the evolutionary relationship of flowering-related genes betweenand.

; flowering genes; evolution; regulatory pathway;expression analysis

2018-11-16;

2019-04-15;

2019-05-08.

10.3724/SP.J.1006.2019.84159

李加納, E-mail: ljn1950@swu.edu.cn, Tel: 023-68250642

E-mail: hawer313@163.com

本研究由重慶市民生工程主題專(zhuān)項(xiàng)項(xiàng)目(cstc2016shms-ztzx80020)和高等學(xué)校學(xué)科創(chuàng)新引智基地項(xiàng)目(“111”項(xiàng)目)(B12006)資助。

This study was supported by the Special Project of Chongqing People’s Livelihood Project (cstc2016shms-ztzx80020) and the Project of Intellectual Base for Discipline Innovation in Colleges and Universities (“111” Project) (B12006).

URL:http://kns.cnki.net/kcms/detail/11.1809.S.20190505.1436.008.html