锈赤扁谷盗侵染后小麦自身挥发性化合物动态变化研究

Dynamic Changes of Volatile Compounds in Wheat Afterbeing Infected by the Rusty Grain Beetle

为探究不同储藏周期及不同虫口密度锈赤扁谷盗侵染后小麦自身挥发性化合物的动态变化,采用两种固相微萃取模式(顶空固相微萃取,HS-SPME;浸入固相微萃取,DI-SPME)结合气相色谱-质谱联用(GC-MS)技术进行定性定量测定。基于小麦挥发性化合物的相对含量,通过偏最小二乘法-判别分析(PLS-DA)建立模型,然后找到对分类起关键作用的差异挥发性化合物,最后通过绘制热图和层次聚类分析(HCA)确定差异化合物在不同储藏周期及不同虫口密度锈赤扁谷盗侵染下的变化规律。结果表明:小麦中共定性检测出57种挥发性化合物,锈赤扁谷盗侵染后小麦中共定性检测出61种挥发性化合物,其中包括醛类、醇类、烃类、酸类、酮类、酯类等;锈赤扁谷盗侵染后小麦相比空白对照组,化合物含量均有变化,差异挥发性化合物为γ-亚麻酸、2-十九烷酮、γ-己内酯、十七烷酮、二十九烷、二十七烷、二十七烷醇、1-碘-2-甲基十一烷、壬醛;小麦挥发性化合物的种类及含量随储藏周期变化呈规律性变化。因此,锈赤扁谷盗侵染后小麦的酸类化合物显著增加,导致其霉变,品质下降。

To explore the dynamic changes of the wheat s own volatile compounds after being infected by the rusty grain beetle(Cryptoleste ferrugineus(Stephens))with different storage periods and different insect densities,two solid phase micro-extraction modes(HS-SPME and DI-SPME)combined with Gas Chromatography Mass Spectrometry(GC-MS)technology were established for quantitative and qualitative determination.Based on the relative content of wheat volatile compounds,Partial Least Square Discrimination Analysis(PLS-DA)was used to establish discriminant models.the key role of differential volatile compounds in classification was found.Finally,a heat map and used Hierarchical Cluster Analysis(HCA)was drawn to determine the variation of different compounds under different storage periods and different insect densities.The results showed that 57 volatile compounds were qualitatively detected in wheat,and 61 volatile compounds were qualitatively detected in wheat after the rusty grain beetle was infected,including aldehydes,alcohols,hydrocarbons,acids,ketones,Esters etc;the content of compounds in wheat after the rusty grain beetle was infected compared with the blank control group.The difference volatile compounds wereγ-linolenic acid,2-nonadecanone,γ-caprolactone,17-Alkanone,29-octane,27-heptane,27-heptanol,1-iodo-2-methylundecane,nonanal;the types and contents of wheat volatile compounds changed regularly with the storage period.As a result,the acid compounds of wheat increased significantly after being infected by the rusty grain beetle,resulting in its mildew and reduced quality.