Abstract

The aim of the present study was to reveal the species composition of Fusarium fungi found in soybean mycobiota from the various regions of Russia, as well as to describe the physiological and biochemical characteristics of strains. The taxonomic status of 21 Fusarium strains isolated from seeds, stems and roots of soybean plants was clarified in consequence of the phylogenetic analysis of the fragment of translation elongation factor EF-1α gene. Five fungal species have been identified: F. oxysporum (11 strains), F. equiseti (4), F. proliferatum (3), F. solani (2), as well one strain of F. commune, which was found for the first time in soybean mycobiota in Russia. The morphological and cultural characteristics of the strains and their pathogenicity to leaves of two soybean cultivars in the laboratory conditions were also analyzed. At the cultivation of Fusarium fungi on potato-sucrose agar medium, the optimal temperature range for the growth of all isolates has been established as 25–30°C, at which the largest colony diameter 68.5–74.0 mm was found in F. equiseti and F. commune strains, and the smallest colonies (49.5–55.8 mm) was detected in F. solani strains. Three F. oxysporum strains and one F. commune strain, isolated from the stems, were characterized by high pathogenicity to leaves of two soybean cultivars. These strains caused the necrosis of leaves of cv. Isidor in the range of average length 16.7–21.7 mm, and the necrosis of leaves of cv. Selecta 201 in the range of 10.7–23.3 mm. At the same time, the most of Fusarium strains (52–67% depending on the soybean cultivar) were non-pathogenic. A high intraspecific variability of pathogenicity to soybean leaves was noted among F. oxysporum and F. proliferatum strains.

中文翻译：

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大豆真菌群中镰刀菌的多样性和致病性

摘要

本研究的目的是揭示俄罗斯不同地区大豆菌群中发现的镰孢菌的物种组成，并描述菌株的生理和生化特征。通过对翻译延伸因子EF-1α基因片段的系统发育分析，阐明了从大豆种子、茎和根中分离的21个镰刀菌菌株的分类地位。已鉴定出五种真菌：尖孢镰刀菌（11 株）、木贼镰刀菌（4 株）、增殖镰刀菌（3 株）、茄镰刀菌(2)，还有一株F. commune，是在俄罗斯首次在大豆菌群中发现的。并在实验室条件下分析了该菌株的形态和培养特征及其对两个大豆品种叶片的致病性。在马铃薯蔗糖琼脂培养基上培养镰孢菌时，所有分离株生长的最佳温度范围已确定为 25-30°C，在该温度范围内，木贼镰孢菌的最大菌落直径为 68.5-74.0 mm， F. commune 菌株，在F. solani菌株中检测到最小的菌落（49.5-55.8 mm）。三种尖孢镰刀菌菌株和一种普通镰刀菌菌株该菌株是从茎中分离出来的，对两个大豆品种的叶子具有高致病性。这些菌株导致 cv 的叶子坏死。Isidor的平均长度为16.7-21.7毫米，cv. Isidor的叶子坏死。Selecta 201 的范围为 10.7–23.3 毫米。同时，大多数镰刀菌菌株（52-67%，取决于大豆品种）是非致病性的。在尖孢镰刀菌和增殖镰刀菌菌株中，对大豆叶片的致病性存在高度种内变异。