红阳猕猴桃成熟过程中LOX基因的表达与香气成分变化关系的研究

The Relationship Between The Expression Of Lipoxygenase and Flavor Components At Different Brix Levels Of Hongyang Kiwifruit

摘要:

猕猴桃挥发性香气是非常重要的食味品质。本文研究了红阳猕猴桃在成熟过程中的香气成分变化，并进一步研究红阳猕猴桃脂氧合酶（Lipoxygenase，LOX，EC1.13.11.12）基因表达量的差异对香气成分的影响。通过测定白利糖度（Brix）表征红阳猕猴桃在成熟过程中的不同成熟度；采用顶空-固相微萃取/气相色谱-质谱联用仪（Head-Space Solid-Phase Micro extraction/Gas Chromatography–Mass Spectrometry, HS-SPME/GC–MS）对红阳猕猴桃在不同成熟阶段的香气成分进行分析；利用实时定量PCR（Real-time Quantitative PCR）技术测定LOX基因家族6个成员（AcLox1、AcLox2、AcLox3、AcLox4、AcLox5，AcLox6）的表达量并初步分析其与红阳猕猴桃香气成分变化之间的关系。结果表明，不同成熟度（Brix分别为6.5、10，13和16）红阳猕猴桃的香气有明显差异，主要的香气成分随成熟度的增加呈现明显变化。酯类成分的含量显著增加，醇类和醛类成分的含量显著减少；随着成熟度的增加，LOX基因家族中AcLox1和AcLox5的表达量显著提高，而AcLox2、AcLox3、AcLox4、AcLox6的表达量则呈现下降趋势。该研究结果为猕猴桃的香气的生物合成提供了思路，为猕猴桃分子标记辅助育种提供了理论基础。

Abstract:

The volatile flavor of kiwifruit is a very important taste quality. The changes of flavor components of Hongyang kiwifruit at different brix levels, and the relationship between the expression of Lipoxygenase (LOX， EC1.13.11.12）and flavor changes were investigated. With the measurement of a sugar concentration detector, the samples of Hongyang kiwifruit in different ripening stages were expressed as different brix levels, including 6.5，10，13 and 16. By using the technique of HS-SPME/GC-MS, the flavor components of Hongyang kiwifruit with different brix values were determined. The results showed that the content of esters increased whereas the contents of alcohol and aldehyde decreased, when the brix values of kiwifruit increased. According to the analysis of Quantitative real-time PCR, the expression level of LOX family members in Hongyang kiwifruit were observed, and the results indicated that the expression of AcLox1 and AcLox5 increased but AcLox2, AcLox3, AcLox4, and AcLox6 decreased with the increasing of brix values. Overall, the results suggested that the molecular biology technology may be used as the potential approach to control the flavor of Hongyang kiwifruit and the results can provide a theoretical basis for the molecular mark assisted breeding of kiwifruit.