Wu Hong-Sheng, Raza Waseem, Fan Jia-Qin, Sun Yong-Gang, Bao Wei, Shen Qi-Rong
College of Resources and Environmental Sciences, Nanjing Agricultural University, China.
J Agric Food Chem. 2008 Feb 27;56(4):1316-21. doi: 10.1021/jf0726482. Epub 2008 Jan 23.
Long-term monoculture of watermelon leads to frequent occurrence of watermelon fusarium wilt caused by Fusarium oxysporum f.sp. niveum (FON). Some allelochemicals contained in watermelon root exudates and decaying residues are possibly responsible for promoting the wilt disease. The purpose of this study was to evaluate the allelopathic effect of artificially applied cinnamic acid on FON. Results demonstrated that hyphal growth of FON was strongly inhibited by cinnamic acid. At the highest concentration of cinnamic acid, the biomass in liquid culture was decreased by 63.3%, while colony diameter, conidial germination on plates, and conidial production in liquid culture were completely inhibited. However, mycotoxin production and activity of phytopathogenic enzymes were greatly stimulated. Mycotoxin yield, pectinase activity, proteinase activity, cellulase activity, and amylase activity were increased by 490, 590, 760, 2006, and 27.0%, respectively. It was concluded that cinnamic acid dramatically stimulated mycotoxin production and activities of hydrolytic enzymes by FON but inhibited growth and germination of FON. The findings presented here indicate that cinnamic acid is involved in promoting watermelon fusarium wilt.
长期单一栽培西瓜会导致由尖孢镰刀菌西瓜专化型（FON）引起的西瓜枯萎病频繁发生。西瓜根系分泌物和腐烂残体中含有的一些化感物质可能是导致枯萎病的原因。本研究的目的是评估人工施用肉桂酸对FON的化感作用。结果表明，肉桂酸强烈抑制FON的菌丝生长。在肉桂酸最高浓度下，液体培养中的生物量减少了63.3%，而平板上的菌落直径、分生孢子萌发以及液体培养中的分生孢子产生均被完全抑制。然而，霉菌毒素的产生和植物致病酶的活性受到极大刺激。霉菌毒素产量、果胶酶活性、蛋白酶活性、纤维素酶活性和淀粉酶活性分别提高了490%、590%、760%、2006%和27.0%。得出的结论是，肉桂酸显著刺激FON产生霉菌毒素和水解酶的活性，但抑制FON的生长和萌发。此处呈现的研究结果表明，肉桂酸参与促进西瓜枯萎病。
