Root-knot nematode (RKN), Meloidogyne incognita, is one of the most lingering and difficult to manage pest of black pepper in India. The options for controlling RKN are becoming increasingly limited due to the potential risk involved in environmental and health hazards. Biological control using Pasteuria is one of the most effective and efficient ways of nematode management. Pasteuria spp. are obligate parasites of plant-parasitic nematodes and completely inhibit their fecundity. There is also a tremendous opportunity for the discovery of native strains adapted to local environmental conditions and nematode species. Therefore, in the present study, efforts were made to isolate the native strain of Pasteuria from the fields of black pepper. Random sampling was done from black pepper-growing areas of Kerala and Karnataka states of India. Out of 39 samples, Pasteuria was found in 8 samples from the fields of ICAR-IISR, Kozhikode, Kerala, India. The host range study revealed that the identified Pasteuria strain was very specific to M. incognita and completed its life cycle in RKN. Infected females laid no eggs or egg masses; thus, Pasteuria prohibited the total fecundity of the nematodes. The Pasteuria strain was named as IISR-MiP for it was found in the fields of ICAR-IISR and its specificity towards M. incognita. The average size of the identified Pasteuria strain IISR-MiP endospore was 2.75 μm. Light as well as scanning electron micrographs revealed 3 types of endospore attachments viz., conventional, inverted, and sideways. Further, it was found that endospores attached to the nematode cuticle in the maximum number in a conventional type of attachment (87.62%), followed by inverted (6.55%) and sideways attachments (5.82%). The inverted and sideways attachments were unique to the biology of Meloidogyne-Pasteuria interactions, indicating the presence of collagen-like fibres on the entire surface of Pasteuria endospores. Pasteuria strain IISR-MiP had the potential biocontrol capabilities and provided an opportunity for its evaluation against M. incognita on black pepper under field conditions.

中文翻译：

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印度黑胡椒田中寄生根结线虫Meloidogyne incognita的巴斯德氏菌的分离和鉴定

根结线虫（Metalogyne incognita）是印度最持久，最难处理的黑胡椒害虫之一。由于涉及环境和健康危害的潜在风险，控制RKN的选项越来越受到限制。使用巴斯德氏菌的生物防治是线虫管理的最有效方法之一。巴斯德氏菌 是植物寄生线虫的专性寄生虫，可完全抑制其繁殖力。发现适应当地环境条件和线虫物种的天然菌株的机会也很大。因此，在本研究中，人们努力从黑胡椒领域中分离出巴斯德氏菌的天然菌株。从印度喀拉拉邦和卡纳塔克邦的黑胡椒种植区进行了随机抽样。在39个样本中，从印度喀拉拉邦Kozhikode的ICAR-IISR领域的8个样本中发现了巴斯德氏菌。寄主范围研究表明，鉴定出的巴斯德氏菌菌株对隐孢子虫非常有特异性，并在RKN中完成了其生命周期。被感染的雌性未产卵或卵团；因此，巴斯德氏菌禁止了线虫的全部繁殖力。巴斯德氏菌株被命名为IISR-MiP，是因为它在ICAR-IISR领域发现，并且对隐杆线虫具有特异性。鉴定出的巴斯德氏菌IISR-MiP内生孢子的平均大小为2.75μm。光和扫描电子显微照片揭示了三种类型的内生孢子附着，即常规的，倒置的和侧向的。此外，发现在常规类型的附着中，附着在线虫表皮上的内生孢子数量最多（87.62％），其次是倒置（6.55％）和侧向附件（5.82％）。倒立和侧向附着是Meloidogyne-Pasteuria相互作用的生物学所独有的，表明巴斯德氏菌内生孢子整个表面上都存在胶原样纤维。巴斯德氏菌IISR-MiP具有潜在的生物防治能力，并为其在野外条件下对黑胡椒的隐枝线虫进行评估提供了机会。