Msomi Mhlonipheni, Nogemane Noluyolo, More Garland, Prinsloo Gerhard
Department of Agriculture and Animal Health, University of South Africa, Florida Science Campus, Johannesburg, Gauteng, South Africa.
CAES Laboratories, College of Agriculture and Environmental Sciences, University of South Africa, Johannesburg, Gauteng, South Africa.
Chem Biodivers. 2025 Jul 22:e01243. doi: 10.1002/cbdv.202501243.
Maize is an important crop worldwide with approximately 1200 million tons consumed and a market size worth $143 billion. Environmental stress influence production of crops and mitigating these ensures optimum production. Dicarboxylic acids are known as emulsifying agents that mitigate various stresses in plants. Previous reports have shown that mixtures of dicarboxylic acids like azelaic and sebacic acid are equally important for plants and have improved plant resistance to stress by directly or indirectly affecting metabolic components. In this study, maize plants in their six-leaf (V6) growth stage were sprayed with a mixture of dicarboxylic acids (photon) to investigate the effect of priming on the metabolic profile of maize. A nontargeted H-NMR-based metabolic approach was used to determine the metabolic responses of maize sprayed with photon and grown under the same conditions. Leaf samples were collected at various time points (1 h, 2 h, 12 h, 24 h, 1 week, 2 weeks, and 3 weeks) after application of photon. Orthogonal partial least squares-discriminant analysis (OPLS-DA) revealed various metabolites that were involved in tolerance to plant stress. A significant increase in salicylic acid (SA) and azelaic acid (AzA) was observed in photon-treated samples compared to the controls, and it was also responsible for an increase in amino acids (GABA, alanine, and asparagine) and sugars (sucrose, maltose, and trehalose). In addition, malate and aconitate accumulated after 2 h of treatment and were found to be present in higher concentrations in the treated maize leaf extracts. Since SA was identified as one of the major compounds in treated plants, the enzymatic antioxidants (SOD, CAT, and SOD) were further evaluated. Limited SOD and CAT activity at concentrations ranging from 16.63 to 3.91 µg/mL was detected. The POD showed the lowest activity with no significant differences between photon-treated and untreated extracts. The results indicate that maize plants treated with photon showed appreciable changes in various metabolites, although no significant priming effect on antioxidant enzyme activities was detected. Therefore, the priming effect is proposed to involve the SAR in maize.
玉米是全球重要的作物，年消耗量约为12亿吨，市场规模达1430亿美元。环境胁迫会影响作物产量，减轻这些胁迫可确保实现最佳产量。二羧酸被认为是能减轻植物各种胁迫的乳化剂。先前的报告表明，壬二酸和癸二酸等二羧酸混合物对植物同样重要，它们通过直接或间接影响代谢成分提高了植物的抗逆性。在本研究中，对处于六叶期（V6）的玉米植株喷施二羧酸混合物（photon），以研究引发处理对玉米代谢谱的影响。采用基于非靶向氢核磁共振的代谢方法来确定喷施photon并在相同条件下生长的玉米的代谢反应。在喷施photon后的不同时间点（1小时、2小时、12小时、24小时、1周、2周和3周）采集叶片样本。正交偏最小二乘判别分析（OPLS-DA）揭示了多种与植物胁迫耐受性相关的代谢物。与对照相比，在photon处理的样本中观察到水杨酸（SA）和壬二酸（AzA）显著增加，这也导致了氨基酸（γ-氨基丁酸、丙氨酸和天冬酰胺）和糖类（蔗糖、麦芽糖和海藻糖）的增加。此外，处理2小时后苹果酸和乌头酸积累，且在处理后的玉米叶片提取物中浓度更高。由于SA被确定为处理后植物中的主要化合物之一，因此进一步评估了酶促抗氧化剂（超氧化物歧化酶、过氧化氢酶和过氧化物酶）。在浓度范围为16.63至3.91μg/mL时检测到有限的超氧化物歧化酶和过氧化氢酶活性。过氧化物酶活性最低，photon处理和未处理的提取物之间无显著差异。结果表明，喷施photon的玉米植株在各种代谢物上表现出明显变化，尽管未检测到对抗氧化酶活性有显著的引发效应。因此，推测引发效应涉及玉米中的系统获得性抗性。
