Abstract：
Agricultural Productivity and plant health are threatened by the root-knot nematode. The use of biocontrol agents reduces the need for chemical nematicides and improves the general health of agricultural ecosystems by offering a more environmentally friendly and sustainable method of managing nematode infestations. Plant-parasitic nematodes can be efficiently managed with the use of entomopathogenic nematodes (EPNs), which are widely used biocontrol agents. This study focused on the nematicidal activity of the secondary metabolites present in the bacteria Ochrobactrum sp. identified in the EPN, Heterorhabditisindica against Root-Knot Nematode (Meloidogyne incognita). Its effect on egg hatching and survival of juveniles of root- knot nematode (RKN) was examined. The ethyl acetate component of the cell-free culture (CFC) filtrate of the Ochrobactrum sp. bacteria was tested at four different concentrations (25 %, 50 %, 75 % and 100 %) along with broth and distilled water as control. The bioactive compounds of Ochrobactrum sp. bacteria showed the highest suppression of M. incognita egg hatching (100 %) and juvenile mortality (100 %) at 100 % concentration within 24 h of incubation. In this study, unique metabolite compounds were identified through the Gas Chromatography- Mass Spectrometry (GC-MS) analysis, which were found to have anti- nematicidal activity. In light of this, molecular docking studies were conducted to determine the impact of biomolecules from Ochrobactrum sp. using significant proteins of M. incognita, such as calreticulin, sterol carrier protein 2, flavin-containing monooxygenase, pectate lyase, candidate secreted effector, oesophageal gland cell secretory protein and venom allergen-like protein. The results also showed that the biomolecules from Ochrobactrum sp. had a significant inhibitory effect on the different protein targets of M. incognita. 3-Epimacronine and Heraclenin were found to inhibit most of the chosen target protein. Among the targets, the docking analysis revealed that Heraclenin exhibited the highest binding affinity of -8.6 Kcal/mol with the target flavin- containing monooxygenase. Further, the in vitro evaluation of 3- Epimacronine confirmed their nematicidal activity against M. incognita at different concentrations. In light of this, the present study has raised awareness of the unique biomolecules of the bacterial symbiont Ochrobactrum sp. isolated from H. indica that have nematicidal properties.
摘要：
根结线虫严重威胁着农业生产力和植物健康。生物防治剂的使用减少了对化学线虫的需求，并通过提供一种更环保和可持续的方法来管理线虫侵染，从而改善了农业生态系统的总体健康。使用昆虫病原线虫（EPN）可以有效地管理植物寄生线虫，被认为是非常有前途的生物防治剂。这项研究的重点是细菌Ochrobactrumsp。中存在的次生代谢产物的杀线虫活性。在EPN中确定，异株根结线虫（Meloidogyneincognita）。研究了其对根结线虫（RKN）幼体卵孵化和存活的影响。苍白杆菌属无细胞培养物（CFC）滤液中的乙酸乙酯成分。细菌在四种不同的浓度(25%，50%,75％和100％）以及肉汤和蒸馏水作为对照。苍白杆菌属的生物活性化合物。细菌在孵化24小时内以100％的浓度显示出最高的隐身支原体卵孵化（100％）和幼体死亡率（100％）。在这项研究中,独特的代谢产物化合物通过气相色谱-质谱(GC-MS)分析,被发现具有抗线虫活性。鉴于此,进行了分子对接研究，以确定来自苍白杆菌属的生物分子的影响。使用隐身分枝杆菌的重要蛋白质，如钙网蛋白，甾醇载体蛋白2，含黄素单加氧酶，果胶酸裂解酶，候选分泌效应子，食管腺细胞分泌蛋白和毒变应原样蛋白。结果还表明，来自苍白杆菌属的生物分子。对隐身支原体的不同蛋白质靶标有明显的抑制作用。发现3-Epimacronine和Heraclenin抑制大多数选择的靶蛋白。在目标中，对接分析显示，Heraclenin与目标含黄素单加氧酶的结合亲和力最高，为-8.6Kcal/mol。Further,3-Epimacronine的体外评估证实了它们在不同浓度下对M.incognita的杀线虫活性。鉴于此,本研究提高了人们对细菌共生体嗜铬杆菌的独特生物分子的认识。分离自具有杀线虫特性的India。
