Laboratoire Génie Microbiologique et Applications, Faculté des Sciences de la Nature et de la Vie, Université Constantine 1, Constantine, Algeria.
Environ Sci Pollut Res Int. 2014 Apr;21(8):5619-27. doi: 10.1007/s11356-014-2512-9. Epub 2014 Jan 14.
Sulfonylurea herbicides are widely used on a wide range of crops to control weeds. Chevalier® OnePass herbicide is a sulfonylurea herbicide intensively used on cereal crops in Algeria. No information is yet available about the biodegradation of this herbicide or about its effect on the bacterial community of the soil. In this study, we collected an untreated soil sample, and another sample was collected 1 month after treatment with the herbicide. Using a high-resolution melting DNA technique, we have shown that treatment with Chevalier® OnePass herbicide only slightly changed the composition of the whole bacterial community. Two hundred fifty-nine macroscopically different clones were isolated from the untreated and treated soil under both aerobic and microaerobic conditions. The strains were identified by sequencing a conserved fragment of the 16S rRNA gene. The phylogenetic trees constructed using the sequencing results confirmed that the bacterial populations were similar in the two soil samples. Species belonging to the Lysinibacillus, Bacillus, Pseudomonas, and Paenibacillus genera were the most abundant species found. Surprisingly, we found that among ten strains isolated from the treated soil, only six were resistant to the herbicide. Furthermore, bacterial overlay experiments showed that only one resistant strain (related to Stenotrophomonas maltophilia) allowed all the sensitive strains tested to grow in the presence of the herbicide. The other resistant strains allowed only certain sensitive strains to grow. On the basis of these results, we propose that there must be several biodegradation pathways for this sulfonylurea herbicide.
磺酰脲类除草剂被广泛应用于多种作物以控制杂草。Chevalier® OnePass 除草剂是一种在阿尔及利亚谷物作物上大量使用的磺酰脲类除草剂。目前尚无关于该除草剂生物降解的信息，也不知道它对土壤细菌群落的影响。在这项研究中，我们采集了未处理的土壤样本，另一个样本是在使用除草剂 1 个月后采集的。使用高分辨率熔解 DNA 技术，我们表明 Chevalier® OnePass 除草剂处理仅略微改变了整个细菌群落的组成。在好氧和微氧条件下，从未处理和处理的土壤中分离出 259 个宏观上不同的克隆。通过对 16S rRNA 基因的保守片段进行测序来鉴定菌株。基于测序结果构建的系统发育树证实了两个土壤样本中的细菌种群相似。丰度最高的物种属于赖氨酸芽孢杆菌属、芽孢杆菌属、假单胞菌属和类芽孢杆菌属。令人惊讶的是，我们发现从处理过的土壤中分离出的十种菌株中，只有六种对除草剂有抗性。此外，细菌覆盖实验表明，只有一株抗除草剂的菌株（与嗜麦芽窄食单胞菌有关）允许所有测试的敏感菌株在除草剂存在的情况下生长。其他抗性菌株只允许某些敏感菌株生长。基于这些结果，我们提出这种磺酰脲类除草剂可能有几种生物降解途径。
