Department of Nematology, Assam Agricultural University, Jorhat, Assam, India.
Division of Crop Protection, National Rice Research Institute, Cuttack, Odisha, India.
PeerJ. 2023 Jul 28;11:e15779. doi: 10.7717/peerj.15779. eCollection 2023.
has a well-established negative impact on rice yield in transplanted and direct-seeded rice, resulting in yield losses of up to 20 to 90 percent. Studies were undertaken to isolate potential native strains of bio-control agents to manage the devastating Rice Root Knot Nematode (). Eighteen bacterial strains and eleven fungal strains were isolated from the rhizosphere of crops like rice, okra, ash gourd, chili, beans and cucumber, enveloping diverse soil types from the Upper Brahmaputra Valley region of Assam. Six bacterial strains were gram-positive according to morphological results, while twelve others stained negatively. Fifteen bacteria were rod-shaped, two were coccus and one was diplococcus, and all the bacterial isolates showed signs of movement. All the bacterial strains exhibited positivity for gelatin hydrolysis and catalase test. Seven bacteria showed positive, while eleven showed negative reactions to possess the ability to deduce carbon and energy from citrate. The study of the efficacy of the twenty-nine bacterial and fungal isolates tested against second-stage juveniles (J) of revealed that all the bacterial and fungal isolates potentially inhibited the test organism and caused significant mortality over sterile water treatment. The promising bacterial and fungal isolates that exhibited mortality above 50% were identified as BSH8, BTS4, BTS5, BJA15, FJB 11 and FSH5. The strain BSH8 exhibited the best result of mortality, with 80.79% mortality against J of . The strain BTS4 and BTS5 expressed mortality of 71.29% and 68.75% under conditions and were significant. The effective and promising bioagents were identified using the 16 S rRNA sequencing as (BSH8), (BTS4), (BTS5), (BJA15), (FSH5) and (FJB11). These results indicated the microorganism's potential against and its potential for successful biological implementation. Further, the native strains could be tested against various nematode pests of rice in field conditions. Its compatibility with various pesticides and the implication of the potential strains in integrated pest management can be assessed.
它对移栽和直播水稻的产量有显著的负面影响,导致产量损失高达 20%至 90%。本研究旨在从水稻、黄秋葵、冬瓜、辣椒、豆类和黄瓜等作物的根际中分离潜在的本土生物防治剂菌株,以防治破坏性的水稻根结线虫()。从阿萨姆邦上布拉马普特拉河谷地区的不同土壤类型中分离出了 18 株细菌和 11 株真菌菌株。根据形态学结果,其中 6 株细菌为革兰氏阳性,而其余 12 株为革兰氏阴性。15 株细菌为杆状,2 株为球菌,1 株为双球菌,所有细菌分离株均表现出运动迹象。所有细菌分离株均对明胶水解和过氧化氢酶试验呈阳性反应。7 株细菌表现出阳性,而 11 株细菌对能够从柠檬酸盐中推断碳和能量的能力表现出阴性反应。对 29 株细菌和真菌分离株对第二代幼虫(J)的测试结果表明,所有细菌和真菌分离株均能潜在抑制试验生物并导致与无菌水处理相比出现显著死亡率。死亡率超过 50%的有前途的细菌和真菌分离株被鉴定为 BSH8、BTS4、BTS5、BJA15、FJB11 和 FSH5。BSH8 菌株对 的死亡率最高,达到 80.79%。在 条件下,BSH4 和 BTS5 菌株的死亡率分别为 71.29%和 68.75%,差异显著。通过 16S rRNA 测序鉴定有效的有前途的生物制剂为 (BSH8)、 (BTS4)、 (BTS5)、 (BJA15)、 (FSH5)和 (FJB11)。这些结果表明,这些微生物对 具有潜在的防治效果,并且可能成功地进行生物防治。此外,还可以在田间条件下对各种水稻线虫害虫进行本土菌株测试。可以评估其与各种农药的相容性以及潜在菌株在综合虫害管理中的应用。