Under natural conditions, various abiotic and biotic constrains act on the plants. Root-knot nematodes, particularly Meloidogyne incognita serve as one of the chief biotic constrains in the agriculture sector, ultimately leading to immense economic losses globally. Nowadays, plant signaling molecules such as gasotransmitters and phytohormones have gained importance for stress-curtailing roles. Therefore, the current study was designed to decode the role of nitric oxide (NO) in growth promotion and stress diminution in Solanum lycopersicum under M. incognita stress. Surface sterilized tomato seeds were pre-treated for 4 h with different concentrations (50, 100 and 200 µM) of sodium nitroprusside (SNP, NO donor). The treated seeds were allowed to germinate in autoclaved petri plates lined with filter paper. After germination, the seedlings were inoculated with 5 s-stage juveniles per seedling. The experiment was terminated after 10 days of nematode inoculation and different parameters were assessed. Results revealed that inoculation of nematodes reduced the growth in terms of length and weight and level of photosynthetic pigments of S. lycopersicum seedlings and increased the content of stress markers such as hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) leading to oxidative stress in the seedlings. Additionally, the activity of enzymatic and non-enzymatic antioxidants and the content of proline and phenolic compounds were found to be enhanced in nematode-inoculated seedlings. Glutathione tagging was also assessed using a confocal microscope, indicating an enhanced glutathione level in nematode-inoculated seedlings. Seed priming with SNP mitigated the negative effect of nematode stress by alleviating the level of stress markers (H₂O₂ and MDA) and further elevating the activity of antioxidants and phenolic compounds. Seed priming with SNP also resulted in a significant decrease in number of galls formation and increased the growth of S. lycopersicum seedlings. These findings indicate a crucial role of NO in elemental defense response during nematode stress in plants.

在自然条件下，各种非生物和生物约束作用于植物。根结线虫，尤其是根结线虫是农业领域的主要生物限制因素之一，最终导致全球范围内的巨大经济损失。如今，植物信号分子（如气体递质和植物激素）在减轻压力方面发挥着重要作用。因此，本研究旨在破解一氧化氮 (NO) 在南方根结线虫胁迫下番茄生长促进和胁迫减轻中的作用。用不同浓度（50、100 和 200 µM）的硝普钠（SNP，NO 供体）预处理表面消毒的番茄种子 4 小时。使经处理的种子在衬有滤纸的高压灭菌培养皿中发芽。发芽后，每株幼苗接种 5 s 期幼苗。线虫接种 10 天后终止实验，并评估不同的参数。结果表明，接种线虫降低了S. lycopersicum幼苗的长度和重量以及光合色素水平的生长，并增加了过氧化氢（H ₂ O ₂) 和丙二醛 (MDA) 导致幼苗氧化应激。此外，发现接种线虫的幼苗中酶促和非酶促抗氧化剂的活性以及脯氨酸和酚类化合物的含量得到提高。还使用共聚焦显微镜评估了谷胱甘肽标记，表明接种线虫的幼苗中谷胱甘肽水平有所提高。用 SNP 引发的种子通过降低胁迫标记物（H ₂ O ₂和 MDA）的水平并进一步提高抗氧化剂和酚类化合物的活性来减轻线虫胁迫的负面影响。用 SNP 引发的种子还导致虫瘿形成数量显着减少，并促进了S. lycopersicum的生长幼苗。这些发现表明 NO 在植物线虫胁迫期间的元素防御反应中起着至关重要的作用。