Basumatary Binita, Das Debanand, Choudhury B N, Dutta Pranab, Bhattacharyya Ashok
Department of Nematology, Assam Agricultural University, Jorhat 785013, Assam, India.
School of Crop Protection, College of Post Graduate Studies in Agricultural Sciences, Central Agricultural University, Umiam.
J Nematol. 2021 Dec 21;53. doi: 10.21307/jofnem-2021-104. eCollection 2021.
Fifteen endophytic bacteria were isolated from leaves and stems of and collected from different locations of the Jorhat district of Assam and characterized by morphological, cultural, biochemical and molecular approaches. An in vitro study was carried out to evaluate their potentiality as biological control agents against second stage juvenile of the root-knot nematode, race2. Thirty second stage juveniles (J) of race 2 were exposed to cell free culture filtrates of all the 15 bacterial endophytes in a sterile cavity block at a concentration of S(100%), S/2(50%), S/4(25%), S/6(17%) and S/10(10%) for a duration of 6, 12, 24, and 48 hr. The results revealed that all the isolates had the potentiality to significantly increase the mortality of the second stage juveniles (J). The percent mortality was directly proportional to the duration of exposure time and the concentration of the culture filtrate. The isolate BETL2 showed the best result with 81.47% mortality of juveniles followed by isolates BETL4 (81.43%), BETLI (79.07%), BETS2 (78.87%), and BETL6 (78.17%). The 16S rRNA sequence amplification results indicated that these isolates were (BETL2), (BETL4), (BETL1), (BETS2), and (BETL6). The four most efficient isolates were structurally analyzed using a scanning electron microscope and this revealed that the length and breadth of isolates-BETLI, BETL2, BETL4, and BETS2 were 701.70 nm × 348.30 nm, 954.10 nm × 303.10 nm, 984.10 nm × 332.90 nm and 1422.00 nm × 742.00 nm, respectively. The result of the present study indicated that the above four novel strains of endophytic bacterial isolates enhance the mortality of J of race2 and has the potentiality as biological control agents against .
从阿萨姆邦乔哈特地区不同地点采集的[植物名称]的叶片和茎中分离出15株内生细菌，并通过形态学、培养学、生物化学和分子生物学方法对其进行了鉴定。进行了一项体外研究，以评估它们作为生物防治剂对抗根结线虫2号小种第二代幼虫的潜力。将30条根结线虫2号小种的第二代幼虫置于无菌腔室块中，分别暴露于15种细菌内生菌的无细胞培养滤液中，浓度分别为S(100%)、S/2(50%)、S/4(25%)、S/6(17%)和S/10(10%)，持续6、12、24和48小时。结果表明，所有分离株都有显著提高第二代幼虫死亡率的潜力。死亡率百分比与暴露时间和培养滤液浓度成正比。分离株BETL2表现出最佳效果，幼虫死亡率为81.47%，其次是分离株BETL4(81.43%)、BETL1(79.07%)、BETS2(78.87%)和BETL6(78.17%)。16S rRNA序列扩增结果表明，这些分离株分别为具体细菌名称、具体细菌名称、具体细菌名称、具体细菌名称和具体细菌名称。使用扫描电子显微镜对四种最有效的分离株进行了结构分析，结果显示分离株BETL1、BETL2、BETL4和BETS2的长度和宽度分别为701.70纳米×348.30纳米、954.10纳米×303.10纳米、984.10纳米×332.90纳米和1422.00纳米×742.00纳米。本研究结果表明，上述四种新型内生细菌分离株可提高根结线虫2号小种第二代幼虫的死亡率，具有作为生物防治剂对抗根结线虫的潜力。
