黄瓜脂氧合酶(LOX)基因与果实特征芳香物质的关系研究

Study on the Relationship between the Gene Expression of Lipoxygenase and Characteristic Aroma Substance in Cucumber Fruit

本研究比较了8个黄瓜品系果肉中特征芳香物质2E,6Z-壬二烯醛的含量,并以2E,6Z-壬二烯醛含量高的EP326和含量低的DE843为材料,分析了这2个品系果实发育过程中2E,6Z-壬二烯醛含量变化及5个9-LOX家族基因的表达变化。结果表明:EP326和DE843果肉中的2E,6Z-壬二烯醛含量呈先上升后下降的变化趋势,且分别在授粉后9 d和12 d出现最大值;9-LOX家族的Csa007837主要在果肉中表达;EP326、DE843果肉中Csa007837表达量的变化与对应品系中的2E,6Z-壬二烯醛含量的变化趋势基本一致;EP326果肉中Csa007837表达量在授粉后不同时期均明显高于DE843,且分别在EP326、DE843授粉后9 d和12 d出现最大值;相关性分析表明,EP326、DE843果肉中2E,6Z-壬二烯醛含量与Csa007837基因表达量之间均呈显著性正相关,而与其它4个9-LOX家族基因无相关性。因此,推测Csa007837基因对控制黄瓜果实芳香物质的合成起到了关键作用。

The content of 2E, 6Z-nonadienal in pulp of 8 cucumber lines were evaluated in present study. EP326 with high 2E, 6Z-nonadienal content and DE843 with low 2E, 6Z-nonadienal content were selected as materials.The contents of 2E, 6Z-nonadienal in EP326 and DE843 during the fruit development were analyzed, and the gene expression level of five LOX genes which belong to 9-LOX family were also compared. The results indicated that the content of 2E, 6Z-nonadienal in pulp of EP326 and DE843 showed rose first, then fell, and reached the highest levels at the 9thday and 12 thday after pollination, respectively. Csa007837 was mainly expressed in pulp, and the gene expression tendency was in corresponding with the content of 2E, 6Z-nonadienal in EP326 and DE843. In accordance with the content of 2E, 6Z-nonadienal, the gene expression of Csa007837 in pulp of EP326 was higher than that in DE843, and reached the highest level in EP326 and DE843 in the 9th and 12 th day after pollination,respectively. The correlation analysis indicated that the gene expression of Csa007837 was correlated positively with 2E, 6Z-nonadienal content in EP326 and DE843, while other four 9-lox family genes did not show correlation with 2E, 6Z-nonadienal contents. Therefore, we speculated that Csa007837 might play an importantrole in the aroma substance formation in cucumber fruit.