Wang Chuanwen, Huang Yu, Zhao Jiayi, Ma Yuyun, Xu Xiaolin, Wan Qiang, Li Hao, Yu He, Pan Baoliang
College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
Vet Parasitol. 2019 Jul;271:57-63. doi: 10.1016/j.vetpar.2019.06.011. Epub 2019 Jun 18.
The poultry red mite, Dermanyssus gallinae, is a blood-feeding ectoparasite that affects egg-laying hens worldwide. Strategies to control this parasite have focused in the use of entomopathogenic fungi, such as Metarhizium anisopliae. However, only a few studies have evaluated the use of Aspergillus oryzae to control D. gallinae and none of them have employed native strains. In the work presented here, a novel entomopathogenic fungus was isolated from a dead D. gallinae. The results of phylogenetic analysis showed 100% similarity between the isolated strain and those of two species, A. oryzae and Aspergillus flavus, and 99.82% similarity with A. parvisclerotigenus, which were in the same branch of the Flavi section of the genus Aspergillus. This entomopathogenic fungus was a non-aflatoxin B1 producer, as shown by the presence of aflatoxin B1 in the conidial infection suspension. Morphological features of fungus in comparison with A. oryzae and A. flavus indicated that the isolated strain belonged to A. oryzae, and was named Aspergillus sp. Dg-1. The pathogenicity of Aspergillus sp. Dg-1 on D. gallinae at different life stages was then assessed under laboratory conditions. The experiments showed that the isolated strain significantly increased the mortality rate in adult mites, up to 24.83 ± 2.25, compared to the mortality rates in the control group, which were 15.17 ± 2.75 (P ＜ 0.05). However, Aspergillus sp. Dg-1 did not have pathogenic effects on the second nymph stage of D. gallinae. Our findings demonstrate that Aspergillus sp. Dg-1 has pathogenic effects on D. gallinae in their adult stage, presenting biocontrol potential against D. gallinae.
鸡皮刺螨（Dermanyssus gallinae）是一种吸食血液的体外寄生虫，影响着全球范围内的产蛋母鸡。控制这种寄生虫的策略主要集中在使用昆虫病原真菌，如绿僵菌（Metarhizium anisopliae）。然而，仅有少数研究评估了米曲霉（Aspergillus oryzae）对鸡皮刺螨的控制作用，且均未使用本地菌株。在本文介绍的研究中，从一只死亡的鸡皮刺螨中分离出一种新型昆虫病原真菌。系统发育分析结果显示，分离菌株与米曲霉和黄曲霉的两个物种的菌株相似度达100%，与拟小菌核曲霉（Aspergillus parvisclerotigenus）相似度为99.82%，它们都在曲霉属黄曲霉组的同一分支中。如分生孢子感染悬液中黄曲霉毒素B1的存在所示，这种昆虫病原真菌不产生黄曲霉毒素B1。与米曲霉和黄曲霉相比，该真菌的形态特征表明分离菌株属于米曲霉，命名为曲霉属Dg - 1菌株（Aspergillus sp. Dg-1）。随后在实验室条件下评估了曲霉属Dg - 1菌株对不同生命阶段鸡皮刺螨的致病性。实验表明，与对照组死亡率15.17±2.75相比，分离菌株显著提高了成年螨的死亡率，高达24.83±2.25（P＜0.05）。然而，曲霉属Dg - 1菌株对鸡皮刺螨的第二若虫阶段没有致病作用。我们的研究结果表明，曲霉属Dg - 1菌株对成年鸡皮刺螨具有致病作用，具有对鸡皮刺螨进行生物防治的潜力。
