蚜害茶树挥发物组分变化的聚类分析

舒茶早(Camellia sinensis cv. ‘shuchazao’)是皖西南产区一种茶树品种。为研究茶蚜取食为害诱导的茶树挥发物释放特征, 运用气相色谱-质谱联用技术, 比较了健康茶梢和蚜害茶梢的挥发物组成和相对含量。结果显示, 健康茶梢挥发物种类(16种)和相对含量较少, 而蚜害茶梢挥发物种类(24种)较为丰富且相对含量增大。对具有显著性差异的挥发物种类进行无监督式聚类分析, 结果表明, 健康茶梢和蚜害茶梢挥发物具有明显的聚类特征。基于差异显著挥发物建立了偏最小二乘法判别分析(PLS-DA)模型。经实验验证, 此模型可较好地区分健康和蚜害茶梢(R²X=0.903, R²Y=0.875)。通过计算变量重要性投影, 结果表明, α-蒎烯、长叶烯-(V4)、苯甲醛、反-2-甲基-2-丁烯酸环丙烯酯、3-己烯醛、莰酮和癸醛这7种重要挥发物的相对含量整体变化对判别健康与蚜害茶梢具有重要作用。研究初步揭示了茶蚜为害茶树挥发物含量变化的特征, 可为制定茶蚜防控策略提供新的理论依据。

Clustering Analysis of Volatile Components from the Tea Plants Infested by Tea Aphid (Toxoptera aurantii)

Shuchazao tea (Camellia sinensis cv. ‘shuchazao’) is a newly cultivated tea species in southwest Anhui, China. To investigate the volatile release profiles of tea aphid (Toxoptera aurantii) infested tea shoots, gas chromatography-mass spectrometry (GC-MS) analysis was used to compare the volatile compositions and relative contents in healthy and infested tea shoots. 16 volatile organic compounds (VOCs) were detected in healthy tea shoots with fewer relative contents, whereas more volatiles (24 VOCs) were released with increasing relative contents in tea plants induced by tea aphid feeding. Unsupervised clustering analysis based on the significantly different volatiles indicated that the volatile profiles in healthy and tea aphid infested tea shoots apparently showed clustering characteristics. A model was created by supervised partial least square discrimination analysis (PLS-DA) for volatiles with statistical significance. By experimental verification, the model could clearly discriminate healthy tea shoots from aphid infested ones (R²X=0.903, R²Y=0.875). By calculating the variable importance for the projection (VIP), seven important volatiles (α-pinene, longifolene-(V4), benaldehyde, E-5,9-undecadien-2-one,6,10-dimethyl-, 3-hexenal, camphor and decanal) were identified which collectively contribute to discrimination between healthy and infested tea shoots. The current work has preliminarily demonstrated the changing patterns in tea plant volatiles after tea aphid infestation to provide novel theoretical guidance for tea aphid management.