摘要:为了解果糖-1，6-二磷酸醛缩酶（fructose-1，6-bisphosphate aldolase，FBA）在油菜抗旱中的作用，揭示油菜干旱胁迫下FBA基因表达量、光合指标、产量等之间的关系，为油菜等作物抗旱性鉴定和抗旱性改良提供依据。以抗旱性强的甘蓝型油菜94005为材料，在初花期进行干旱胁迫处理，以正常浇水作为对照；测定叶片光合参数和FBA酶活性，通过实时荧光定量PCR（RT-qPCR）分析FBA基因的表达量；采用RACE方法对FBA基因进行全长克隆，并对测序结果进行生物信息学分析；复水后生长至成熟期测定产量，分析产量、光合指标、FBA基因表达量等之间的关系。结果表明，随着干旱的加剧，油菜叶片的净光合速率（Pn）、气孔导度（Gs）、蒸腾速率（Tr）、产量均下降，FBA活性和FBA基因的表达量上升。在轻度、中度和重度干旱胁迫下，油菜叶片胞间CO₂浓度（Ci）显著下降，水分利用率（WUE）上升；极度胁迫下，Ci上升，WUE下降；油菜产量、净光合速率与FBA活性和FBA表达量呈显著负相关。FBA基因全长序列1440bp，ORF（开放阅读框）位于60-1172区域，编码370个氨基酸；蛋白分子量为38.51 KDa，等电点6.92；同源性对比显示，甘蓝型油菜FBA基因与拟南芥FBA基因的一致性在87%以上。二级结构预测结果表明FBA蛋白由α-螺旋、无规则卷曲、延伸链以及β-转角组成，4种二级结构元件所占比例分别为43.85%、31.28%、17.60%、7.26%。因此，干旱胁迫下油菜的净光合速率下降、产量降低，随着胁迫的加剧，降低幅度增大。FBA基因与干旱胁迫密切相关，干旱胁迫下，FBA基因主要通过抑制光合、降低蒸腾、促进糖酵解和有氧呼吸等途径来提高植物对干旱胁迫的适应性。



Abstract:This paper aims to understand the function of fructose-1, 6-bisphosphate aldolase (FBA) in drought resistace of apeseed (Brassica napus L.), to reveal the relationship between gene expression and photosynthetic index and yield under drought stress, and to provide a reference for the identification and improvement of drought resistance. The high drought-tolerant rapeseed 94005 as experimental materials, were treated with drought stress during the flowering stage and with normal irrigation as the control group. We measured the photosynthetic parameters and FBA enzyme activities of the leaves and analyzed the expression of FBA through real-time fluorescence quantitative PCR (RT-qPCR). The RACE method was used to get the full-length clone of FBA gene. The sequencing results were analyzed with bioinformatics. After rehydration, the plants growed until maturity and rapeseed yield was measured, meanwhile the relationship was analyzed between gene expression, physiological parameters, yield and so on. The results showed that the rapeseed yield and net photosynthetic rate (Pn), stomatal conductance (Gs), and transpiration rate (Tr) of the leaves were significantly decreased, fructose-1,6-bisphosphate aldolase activity and gene expression were increased with the drought stress level increasing. The intercellular CO₂ concentration (Ci) was decreased and water use efficiency (WUE) was significantly increased under lightly, moderate, and severe stress, while the Ci was increased and WUE was decreased under extreme stress. The correlation analysis showed that the net photosynthetic rate and yield had a significantly negative correlation with FBA activity and the expression of FBA. The full length of FBA was 1440bp, and the ORF was located in 60bp-1172bp, encoding a protein of 370 amino acids with a predicted molecular weight of 38.51 kD and isoelectric point of 6.92. Homology comparison indicated that FBA of rapeseed had a consistency over 87% with Arabidopsis FBA. The secondary structure prediction showed that FBA protein consisted of α-helix, random coil, extending chain, and β-corner, as well as the proportion of four kinds of secondary structural elements was 43.85%, 31.28%, 17.60%, and 7.26%, respectively. The net photosynthetic rate and yield of rapeseed were decreased under drought stress, and the decrease was greater with the enhancement of stress. FBA gene was closely related to drought stress. FBA gene mainly improved plant adaptability to drought stress by inhibiting photosynthesis rate, reducing of transpiration rate, promoting effect of glycolysis, and aerobic respiration under drought stress.





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