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花生黄曲霉侵染力

花匠小妙招
2024-11-09 23:46

摘要：

【背景】黄曲霉（Aspergillus flavus）极易侵染花生等农产品,产生的黄曲霉毒素具有高毒性、致畸性和致癌性,威胁人类和动物健康,造成重大的农业经济损失。【目的】在前期明确我国黄曲霉分布的基础上,进一步探明不同产毒力、不同地理来源的花生黄曲霉侵染特征,为抗黄曲霉花生品种选育,以及黄曲霉毒素污染风险预警与源头控制提供依据。【方法】从我国东北早熟花生区、北方大花生区、长江流域春夏花生交作区及南方春秋两熟花生区等花生主产区分离出的黄曲霉中挑选出不产毒（ND）、中低产毒（0—1 500 μg·kg-1）和高产毒（>1 500 μg·kg-1）黄曲霉102株,采用孢子悬浮液浸泡法接种花生种子,进行黄曲霉侵染等级和侵染指数鉴定,分析不同产毒力、不同地理来源黄曲霉的侵染差异及其相关性。【结果】102株黄曲霉对花生侵染指数分布范围为3.89%—67.50%,侵染指数在31%以上（侵染等级为3级、4级）的中高侵染力菌株占比达54.90%,中高侵染力且高产毒菌株占比为18.63%,主要来自江西樟树和广东湛江;聚类及相关性分析表明,菌株产毒量与侵染指数无显著相关性,但总体上产毒菌株的侵染水平显著高于不产毒菌株,中低产毒和高产毒菌株的侵染指数分别在4级和3级的占比最高;不同地理来源黄曲霉侵染力研究表明,菌株间侵染力存在显著的地域差异,南方和长江流域产区的花生黄曲霉平均侵染指数分别为46.59%、36.12%,侵染指数在3级和4级的占比最高。东北和北方产区黄曲霉平均侵染指数分别为15.72%、27.52%,侵染指数主要分布在1级和2级。其中,南方产区广东省的黄曲霉平均侵染指数最高,为51.89%,东北产区辽宁省的黄曲霉平均侵染指数最低,为15.72%。【结论】明确了花生黄曲霉侵染特征及其与产毒力、地理来源的关系,发现菌株间存在致病力分化现象,不同产毒力等级、不同地区菌株侵染力差异显著,高侵染力菌株在南方和长江流域的占比最高。研究结果可对抗黄曲霉花生品种选育和毒素污染风险预警与精准防控等提供依据。

关键词: 黄曲霉, 黄曲霉毒素, 花生, 产毒力, 侵染力

Abstract:

【Background】Aspergillus flavus can easily infect peanut and other agricultural products, and the aflatoxin produced by A. flavus is highly toxic, teratogenic and carcinogenic, threatening human and animal health and causing significant agricultural economic losses.【Objective】Based on the previous research about the distribution of A. flavus in China, this study aims to further investigate the infection characteristics of A. flavus strains with different toxigenicity and geographical sources, so as to provide scientific basis for screening and breeding of peanut cultivars with resistance to A. flavus, as well as the early risk warning and control of aflatoxin contamination.【Method】A total of 102 strains of A. flavus isolated from different regions (early maturing peanut region in northeast China, large peanut region in north China, intercropping peanut region in spring and summer in Yangtze River, and double cropping peanut region in spring and autumn in south China) of China were identified as non-toxigenicity (ND), medium-low toxigenicity (0-1 500 μg·kg-1) and high toxigenicity (>1 500 μg·kg-1). The soaking method of the spores suspension was used to inoculate peanut seeds to identify the infection grade and infection index of A. flavus, and the infection difference of the strains and their correlation between different toxigenicity and different geographical sources were analyzed.【Result】The infection index of the 102 A. flavus strains to peanut was ranged from 3.89% to 67.50%. The proportion of A. flavus strains with intermediate or strong infectivity (the infection grade was 3 or 4, infection index>31%) accounted for 54.90%, and 18.63% of the total strains, mainly from Zhangshu in Jiangxi Province and Zhanjiang in Guangdong Province, were identified as intermediate or strong infectivity and high toxigenicity strains. Clustering and correlation analysis indicated that there was no significant correlation between the toxigenicity and infection index of A. flavus, however, the infectivity of toxigenic strains was significantly higher than that of the non-toxigenic strains. The infection index of medium-low toxigenicity and high toxigenicity strains accounted for the highest proportion in grade 4 and 3, respectively. Regional differences in the infectivity among the strains were analyzed. The results showed that average infection index of the strains from the south and the Yangtze River regions was 46.59% and 36.12%, respectively, and accounted for the highest proportion in grade 3 and 4. By contrast, the infection index of the strains from the northeast and northern regions was only 15.72% and 27.52%, respectively, and mainly distributed in grade 1 and 2. Strains from Guangdong Province, in the south China, had the highest average infection index (51.89%), while the average infection index of A. flavus in Liaoning Province, the northeast producing area, was the lowest, which was only 15.72%.【Conclusion】The infection characteristics of A. flavus and its relationship with toxigenicity and geographical sources were preliminarily clarified in this research. There was pathogenic differentiation among the strains, and the infectivity of the strains with different toxigenicity grades and geographical origins was significantly different. Strains with strong infectivity are mainly distributed in the south and Yangtze River regions of China. The results of this study are of great importance for the screening and breeding of peanut cultivars with resistance to A. flavus and the accurate early risk warning, prevention and control of aflatoxin contamination.

Key words: Aspergillus flavus, aflatoxin, peanut, toxigenicity, infectivity