Ghareeb Rehab Y, Abdelsalam Nader R, El Maghraby Dahlia M, Ghozlan Mahmoud H, El-Argawy Eman, Abou-Shanab Reda A I
Department of Plant Protection and Biomolecular Diagnosis, Arid Lands Cultivation Research Institute (ALCRI), City of Scientific Research and Technological Applications (SRTA-City), Alexandria, Egypt.
Department of Agricultural Botany, Faculty of Agriculture, Saba Basha, Alexandria University, Alexandria, Egypt.
Front Plant Sci. 2022 May 26;13:870518. doi: 10.3389/fpls.2022.870518. eCollection 2022.
Plant-parasitic nematodes are one of the major constraints to soybean production around the world. Plant-parasitic nematodes cause an estimated $78 billion in annual crop losses worldwide, with a 10-15% crop yield loss on average. Consequently, finding and applying sustainable methods to control diseases associated with soybean is currently in serious need.
In this study, we isolated, purified, characterized, and identified a novel cyanobacterial strain sp. (blue-green alga). Based on its microscopic examination and 16S rRNA gene sequence, the aqueous and methanolic extracts of were used to test their nematicidal activity against hatchability of eggs after 72 h of exposure time and juvenile mortality percentage after 24, 48, and 72 h of exposure time and reduction percentage of galls, eggmass, female number/root, and juveniles/250 soil. Also, the efficacy of the extract on improving the plant growth parameter and chlorophyll content under greenhouse conditions on soybean plant cv. Giza 111 was tested. Finally, the expression of PR-1, PR-2, PR-5, and PR15 (encoding enzymes) genes contributing to plant defense in the case of invasion was studied and treated with extract.
The aqueous and methanolic extracts of sp. had nematicidal activity against . The percentage of mortality and egg hatching of were significantly increased with the increase of time exposure to extract 96.7, 97, and 98 larvae mortality % with S concentration after 24, 48, and 72 h of exposure time. The aqueous extract significantly increased the percentage of Root-Knot nematodes (RKN) of egg hatching, compared with Oxamyl and methanol extract at 96.7 and 97% after 72 h and 1 week, respectively. With the same concentration in the laboratory experiment. Furthermore, water extracts significantly reduced the number of galls in soybean root, egg masses, and female/root by 84.1, 87.5, and 92.2%, respectively, as well as the percentage of J2s/250 g soil by 93.7%. Root, shoot lengths, dry weight, number of pods/plant, and chlorophyll content of soybean treated with water extract were significantly higher than the control increasing by 70.3, 94.1, 95.5, and 2.02%, respectively. The plant defense system's gene expression was tracked using four important pathogenesis-related genes, PR-1, PR-2, PR-5, and PR15, which encode enzymes involved in plant defense.
extract is a potential nematicide against root-knot nematode invasion in soybean.
植物寄生线虫是全球大豆生产的主要限制因素之一。据估计，植物寄生线虫在全球范围内每年造成780亿美元的作物损失，平均导致作物产量损失10%-15%。因此，目前迫切需要寻找并应用可持续的方法来防治与大豆相关的病害。
在本研究中，我们分离、纯化、表征并鉴定了一种新型蓝藻菌株sp.（蓝绿藻）。基于其显微镜检查和16S rRNA基因序列，使用该菌株的水提取物和甲醇提取物测试它们对南方根结线虫卵孵化率（暴露72小时后）以及幼虫死亡率（暴露24、48和72小时后）的杀线虫活性，以及对根结、卵块、雌虫数/根和幼虫数/250克土壤的减少率。此外，还测试了提取物在温室条件下对大豆品种吉萨111的植物生长参数和叶绿素含量的影响。最后，研究并使用该提取物处理了在南方根结线虫入侵情况下有助于植物防御的PR-1、PR-2、PR-5和PR15（编码酶）基因的表达。
该蓝藻菌株的水提取物和甲醇提取物对南方根结线虫具有杀线虫活性。随着暴露于提取物时间的增加，南方根结线虫的死亡率和卵孵化率显著提高（暴露24、48和72小时后，S浓度下幼虫死亡率分别为96.7%、97%和98%）。水提取物显著提高了根结线虫卵的孵化率，在72小时和1周后分别为96.7%和97%，与杀线威和甲醇提取物相比，在相同实验室浓度下。此外，水提取物显著降低了大豆根中的根结数量、卵块数量和雌虫/根数量，分别降低了84.1%、87.5%和92.2%，以及J2s/250克土壤的比例降低了93.7%。用该蓝藻菌株水提取物处理的大豆的根长、地上部长度、干重、每株豆荚数和叶绿素含量均显著高于对照，分别增加了70.3%、94.1%、95.5%和2.02%。使用四个重要的病程相关基因PR-1、PR-2、PR-5和PR15追踪植物防御系统的基因表达，这些基因编码参与植物防御的酶。
该蓝藻菌株提取物是一种潜在的防治大豆根结线虫入侵的杀线虫剂。
