镰刀菌对大蒜根系分泌物的敏感性与其致病力相关分析

Correlation analysis of the sensitivity of Fusarium spp.to garlic root exudates and their pathogenicity to garlic bulb

试验采用菌丝生长速率法测定了大蒜根系分泌物对3种供试植物病原镰刀菌的抑菌活性,并进一步分析了18株从腐烂蒜瓣上分离的尖孢镰刀菌和12株从小麦赤霉病样分离的禾谷镰刀菌对大蒜根系分泌物的敏感性及致病力之间的关系。研究结果表明,大蒜根系分泌物对供试镰刀菌均具有抑制活性,但从腐烂蒜瓣上分离的尖孢镰刀菌对根系分泌物的敏感性低于其他菌株。致病力分析结果表明,供试的18株尖孢镰刀菌均能使蒜瓣发病,但致病力与其对根系分泌物的敏感性无明显相关性;供试的禾谷镰刀菌中对根系分泌物不敏感的4株菌株能侵染蒜瓣,但敏感性高的菌株不能侵染蒜瓣,且根系分泌物对禾谷镰刀菌的抑制率与禾谷镰刀菌致病力之间呈显著的负相关。这表明大蒜根系分泌抑菌物质是根系抵御镰刀菌侵染的重要机制,但一些菌株能对根系分泌物产生抗性,从而侵染大蒜。综上所述,大蒜根系分泌物对镰刀菌具有抑制活性,可以利用大蒜和其他作物间作或轮作控制镰刀菌枯萎病的发生和蔓延,但长期利用大蒜轮作或间作控制土传病害可能面临镰刀菌对大蒜根系分泌物产生抗性,导致防效降低的风险。

The method of mycelia growth rate was used to determine the antifungal activity of garlic root exudates to the Fusarium isolates,and the relationships between the pathogenicity of 18 F. oxysporum isolates from rotten garlic and 12 F. graminearum isolates from wheat scab samples and their sensitivity to garlic root exudates were analyzed. The results indicated that the root exudates of garlic showed antifungal activity to all Fusarium isolates. However,the isolates of F. oxysporum from rotten garlic showed lower sensitivity to the root exudates. Pathoge-nicity tests showed that the 18 isolates of F. oxysporum from rotten garlic could infect garlic,but there was no correlation between the sensitivity of F. oxysporum isolates and their pathogenicity to garlic. Only four isolates of F. graminearum with low sensitivity exhibited pathogenicity to garlic,but the isolates of F. graminearum with high sensitivity could not infect garlic. In addition,there was an apparent negative correlation between antifungal activity of garlic root exudates and pathogenicity of F. graminearum to the garlic. These results indicated that the exudation of inhibitive ingredients in garlic roots was the important defence mechanism of garlic roots against Fu-sarium infection,but some strains could generate resistance to the garlic root exudates. Based on this study,it is known that the root exudates of garlic showed antifungal activity to F.oxysporum and F.graminearum,so garlic may be used for control of root disease by intercropping and rotation with other crops. But after long-term inter-cropping or rotation with other crops,there might be a risk that Fusarium could generate resistance to the garlic root exudates,causing lower control effect.