National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou 510642, China.
Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China.
Int J Biol Macromol. 2024 Oct;277(Pt 4):134459. doi: 10.1016/j.ijbiomac.2024.134459. Epub 2024 Aug 5.
Water stress, a significant abiotic stressor, significantly hampers crop growth and yield, posing threat to food security. Despite the promising potential of nanoparticles (NPs) in enhancing plant stress tolerance, the precise mechanisms underlying the alleviation of water stress using O-Carboxymethyl chitosan nanoparticles (O-CMC-NPs) in maize remain elusive. In this study, we synthesized O-CMC-NPs and delved into their capacity to mitigate water stress (waterlogging and drought) in maize seedlings. Structural characterization revealed spherical O-CMC-NPs with a size of approximately 200 nm. These NPs accumulated near the seed embryo and root tip, resulting in a substantial increase in fresh and dry weights. The application of O-CMC-NPs to water-stressed maize seedlings remarkedly elevated the chlorophyll content and activity of various antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and polyphenol oxidase (PPO). The malondialdehyde (MDA) content was significantly reduced compared to the untreated control. Additionally, the expression of stress-responsive genes, such as ZmSOD, ZmCAT, ZmPOD, ZmTIFY, ZmACO, ZmPYL2, ZmNF-YC12, and ZmEREB180, were significantly upregulated in the O-CMC-NPs treated seedlings. These findings unveil the novel role of O-CMC-NPs in enhancing plant stress tolerance, suggesting their potential application in safeguarding maize seedlings under water stress conditions and facilitating the recovery from oxidative damage.
水分胁迫是一种重要的非生物胁迫因子，严重抑制作物生长和产量，对粮食安全构成威胁。尽管纳米颗粒（NPs）在提高植物抗胁迫能力方面具有广阔的应用前景，但利用 O-羧甲基壳聚糖纳米颗粒（O-CMC-NPs）缓解玉米水分胁迫的确切机制仍不清楚。本研究合成了 O-CMC-NPs，并探讨了其在缓解玉米幼苗水分胁迫（淹水和干旱）中的作用。结构表征显示 O-CMC-NPs 呈球形，大小约为 200nm。这些 NPs 聚集在种子胚和根尖附近，导致鲜重和干重显著增加。将 O-CMC-NPs 应用于水分胁迫下的玉米幼苗可显著提高叶绿素含量和多种抗氧化酶的活性，包括超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、过氧化物酶（POD）和多酚氧化酶（PPO）。与未处理的对照相比，丙二醛（MDA）含量显著降低。此外，O-CMC-NPs 处理的幼苗中应激响应基因如 ZmSOD、ZmCAT、ZmPOD、ZmTIFY、ZmACO、ZmPYL2、ZmNF-YC12 和 ZmEREB180 的表达显著上调。这些发现揭示了 O-CMC-NPs 增强植物抗胁迫能力的新作用，表明其在保护玉米幼苗免受水分胁迫和促进氧化损伤恢复方面具有潜在的应用价值。
