This study clarified the herbicidal activity, crop safety, classification status, and infection process of herbicidal strain HY-02, and laid a foundation for its development and utilization. Strain HY-02 was isolated from the leaves of Rumex patientia L. by the tissue isolation method. The pathogenicity of the strain to six broadleaf weeds and the safety for four common crops were determined by spray inoculation. The taxonomic status of HY-02 was determined by morphology and molecular biology, and the infection process was confirmed by scanning electron microscopy. In vitro leaf experiments showed that strain HY-02 was pathogenic to six broadleaf weeds, Polygonum aviculare L., Elsholtzia densa Benth., Chenopodium album L., Polygonum lapathifolium L., Amaranthus retroflexus L., and Malva verticillata L. The pot experiment of weeds found that the pathogenicity rates for P. aviculare, E. densa, C. album, P. lapathifolium, A. retroflexus, and M. verticillata were 100.00%, 94.44%, 95.24%, 83.33%, 73.02%, and 40.00%, respectively. Strain HY-02 seemed safe for four crops (Hordeum vulgare L., Triticum aestivum L., Vicia faba L., and Pisum sativum L.), but not for Brassica napus L. The strain was identified as Alternaria alternata (Fries) Keissler. Scanning electron microscope observations showed that hyphae invaded leaf tissues from the stomata by destroying epidermal cells. Hyphae rapidly grew and invaded living tissues by obtaining nutrients from the tissues, destroying the whole leaf tissues, and finally forming reticular lesions. Therefore, the HY-02 strain has the potential to be developed into microbial biocontrol agents for weed control.

中文翻译：

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一株除草真菌HY-02的筛选、鉴定及侵染过程观察

本研究阐明了除草菌株HY-02的除草活性、作物安全性、分类状况及侵染过程，为其开发利用奠定了基础。采用组织分离法从酸模叶中分离得到菌株HY-02 。通过喷雾接种测定了该菌株对六种阔叶杂草的致病性和对四种常见作物的安全性。通过形态学和分子生物学确定了HY-02的分类地位，并通过扫描电子显微镜证实了感染过程。离体叶片实验表明，菌株HY-02对萼蓼、密香薷、藜等6种阔叶杂草具有致病性。杂草盆栽试验发现，对扁舟苋、密叶苋、白花苋、反枝苋、反枝锦葵等杂草的致病率较高。M. verticillata分别为 100.00%、94.44%、95.24%、83.33%、73.02% 和 40.00%。菌株 HY-02 对四种作物（大麦、普通小麦、蚕豆和豌豆）似乎是安全的，但对甘蓝型油菜则不然L.该菌株被鉴定为Alternaria alternata (Fries) Keissler。扫描电镜观察表明，菌丝通过破坏表皮细胞从气孔侵入叶组织。菌丝迅速生长并侵入活组织，从组织中获取营养，破坏整个叶组织，最后形成网状病斑。因此，HY-02菌株具有开发成为杂草控制微生物生防剂的潜力。