在叙利亚沿海地区,昆虫病原线虫(EPN)的发生和分布仍然相对未知。为了解决我们知识的差距,对这些生态系统进行广泛的调查至关重要。这项研究旨在从沿海地区的不同生态系统中分离和识别EPN。根据生境分析了EPNs在栽培和自然环境中的分布,高度,和采样季节因素。在2017年至2020年之间,从821个土壤样本中的27个(3.28%)中回收了EPN,并从375个采样点中的24个(6.4%)中收集了EPN。基于形态学,形态计量学,和分子(ITS)特性,确定了四个EPN物种:印度杂种(51.85%),代表其在沿海地区发生的第一份报告,H.细菌(33.33%),H.巴基斯坦(7.4%),这也是叙利亚首次报道,和Steinernema仿射(7.4%)。在每种类型的生境中,EPN的丰度和恢复频率存在统计学差异。此外,海拔高度和采样季节恢复频率存在统计学差异。协同惯性分析揭示了植被生境中EPNs的分布和发生之间的相关性,高度,和采样季节,以及一些土壤特性。H.indica和H.baciophora与柑橘园有关,低空范围,中等有机质,酸性土壤更具体地说,H.indea分离株与橄榄园相关,菜地,秋天的季节,和粘土,sandy,和沙质壤土。同时,H.细菌分离株与烟草田相关,草原,碱性pH,春天的季节,粉质壤土,和粘土壤土。H.巴基斯坦与梨园有联系,葡萄园,中等pH值,和低有机物质。S、仿射发生在核桃果园,粉土,海拔较高,和冬季。三种天然EPN分离株的毒力水平(S.仿射,H.indea和H.bacteriophora)针对三龄和四龄幼虫(地雷外和内)和T.absoruta的p进行了评估,叙利亚的一种破坏性害虫。所有三个本地EPN物种都表现出感染和杀死昆虫的能力,观察到它们的毒力存在显著差异。这项研究提供了对EPN发生的理解,分布,以及它们在叙利亚可持续虫害控制策略中的应用潜力。
The occurrence and distribution of entomopathogenic nematodes (EPNs) in the Syrian coast regions remain relatively uncharted. To address this gap in our knowledge, an extensive survey of these ecosystems was essential. This study aims to isolate and identify EPNs from diverse ecosystems within the coastal regions. The distribution of EPNs in cultivated and natural environments was analyzed according to habitat, altitude, and sampling season factors. Between 2017 and 2020, EPNs were recovered from 27 out of 821 soil samples (3.28%) and collected from 24 out of 375 sampling sites (6.4%). Based on morphological, morphometric, and molecular (ITS) characteristics, four EPN species were identified:
Heterorhabditis indica (51.85%), representing the first report of its occurrence in the coastal regions, H. bacteriophora (33.33%), H. pakistanense (7.4%), which is also reported for the first time in Syria, and Steinernema affine (7.4%). There were statistical differences in the abundance and recovery frequency of EPNs in each type of habitat. Additionally, there were statistical differences in the altitude and sampling season recovery frequency. Co-inertia analysis revealed correlation between the distribution and occurrence of EPNs in vegetation habitats, altitude, and sampling seasons, as well as some soil characteristics. H. indica and H. bacteriophora were associated with citrus orchards, low-altitude ranges, moderate organic matter, and acidic soil. More specifically, H. indica isolates were correlated with olive orchards, vegetable fields, autumn season, and clay, sandy, and sandy loam soils. Meanwhile, H. bacteriophora isolates were correlated with tobacco fields, grasslands, alkaline pH, spring season, silty loam, and clay loam soils. H. pakistanense was linked to pear orchards, vineyards, moderate pH, and low organic matter. S. affine occurred in walnut orchards, silty soil, higher altitudes, and winter season. The virulence levels of three native EPN isolates (S. affine, H. indica and H. bacteriophora) were evaluated against 3rd and 4th instar larvae (outside and inside mines) and pupae of T. absoluta, a destructive pest in Syria. All three native EPN species exhibited ability to infect and kill the insect, with observed significant differences in their virulence. This study provides an understanding of EPN occurrence, distribution, and their potential for application in sustainable pest control strategies in Syria.