Abstract:

【Objective】 To analyze the volatile substances of healthy leaves, Verticillium wilt and etiolated leaves in cotton and clarify the volatile components related to disease differences were defined in the hope of providing a new reference for the mechanism of the disease in cotton【Methods】 The cotton leaves stated above were employed as the raw material, and the volatile components of the samples were extracted and identified using solid phase microextraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS). The NIST17 spectrum library was searched for the detection results and matched against them. The components were analyzed and calculated by the area normalization method for qualitative and quantitative analysis. Moreover, a multivariate statistical analysis was also utilized to look for distinct substances in the disease symptoms in the leaves.【Results】 A total of 158 volatile components including 21 alcohols, 9 green leaf volatiles, 49 terpenes, 16 alkanes, 38 esters, 5 aromatics, 13 aldehydes, and other compounds was identified by SPME-GC-MS in healthy leaves, Verticillium-infected leaves with withered spot, and Verticillium-infected etiolated leaves, among which, 104 compounds were detected in healthy leaves, 112 in withered spot leaves and 54 in etiolated leaves. In terms of relative compound composition, terpene levels in the withering spot leaves were lower than those in etiolated leaves, although levels of other constituents were higher. Compared with healthy leaves, etiolated and blighted leaves contained 61 and 24 distinctive compounds, respectively, of which 6 common differential compounds were markedly elevated in diseased leaves, and the multiple changes in etiolated leaves were more than that in leaves with withering spots. There were 26 different compounds between withered spot leaves and etiolated leaves. Compared with etiolated leaves, the withered spot leaves had the following differential compounds: (Z) - 2-hexenyl butyrate, (Z) - 3-hexenyl acetate, (Z) - 3-hexenyl hexanoate, γ-Muurolene, and hexadecane, which were significantly up-regulated, whereas (Z) - 3-hexenyl-2-methyl butyrate showed marked down-regulation. 【Conclusion】 The quantity and composition of volatile chemicals in various leaves varied significantly. Terpenes and esters are primarily concentrated in the volatile quantity variance of sick leaves, while terpenes and green leaf volatiles are primarily concentrated in the volatile content variance. Verticillium wilt and cotton interact to produce these substances, which are essential for displaying various sick leaf phenotypes.

Key words: plant volatiles; cotton Verticillium wilt; disease symptom; differential compound

摘要：

【目的】分析棉花中健康叶片、黄萎病枯斑型与黄化型叶片的挥发性物质,研究与病症差异相关的挥发性组分,为棉花抗黄萎病机制研究提供参考。【方法】以健康叶片、黄萎病枯斑型与黄化型棉花叶片为材料,采用固相微萃取(SPME),结合气质联用(GC-MS)技术对样本材料的挥发性物质进行提取和检测,通过面积归一化法对各成分进行分析计算,利用多元统计分析,寻找病症叶片中的差异化合物。【结果】采用SPME-GC-MS方法,从健康叶片、枯斑状病叶和黄化状病叶中共鉴定出158种挥发性化合物,主要包括21种醇、9种绿叶挥发物、49种萜烯、16种烷烃、38种酯、5种芳香烃、13种醛和8种其他类,其中健康叶片检测到的化合物总数为104种、枯斑状病叶为112种、黄化状病叶为54种,不同叶片中的化合物数量差异较大。枯斑状病叶中萜烯类的相对含量小于黄化状病叶,而其他组分的相对含量则均大于黄化病叶。与健康叶片相比,黄化状和枯斑状病叶分别有61、24种差异化合物,其中有6个共有差异化合物均在病症叶片中显著富集,且在黄化状病叶中的倍数变化大于枯斑状病叶。枯斑状与黄化状病叶相比有26种差异化合物,其中特有差异化合物(Z)-2-丁酸己烯酯,(Z)-3-己烯基乙酸酯,(Z)-3-己酸己烯酯,γ-依兰油烯和正十六烷均显著上调,(Z)-3-己烯基2甲基丁酸酯显著下调。【结论】不同病症叶片中挥发性化合物数量和含量具有较大差异,其数量差异主要集中于萜烯类、酯类化合物上,含量差异主要集中于萜烯类和绿叶挥发物上,差异化合物是黄萎病菌与棉花互作的结果,是病症叶片呈现不同表型的关键。

关键词: 植物挥发物, 棉花黄萎病, 病症, 差异化合物