Zou Ying-Ning, Zhang Fei, Srivastava Anoop K, Wu Qiang-Sheng, Kuča Kamil
College of Horticulture and Gardening, Yangtze University, Jingzhou, China.
ICAR-Central Citrus Research Institute, Nagpur, India.
Front Plant Sci. 2021 Jan 12;11:600792. doi: 10.3389/fpls.2020.600792. eCollection 2020.
Soil arbuscular mycorrhizal fungi (AMF) enhance the tolerance of plants against soil moisture deficit stress (SMDS), but the underlying mechanisms are still not fully understood. Polyamines (PAs) as low-molecular-weight, aliphatic polycations have strong roles in abiotic stress tolerance of plants. We aimed to investigate the effect of AMF () inoculation on PAs, PA precursors, activities of PA synthases and degrading enzymes, and concentration of reactive oxygen species in the roots of trifoliate orange () subjected to 15 days of SMDS. Leaf water potential and total chlorophyll levels were comparatively higher in AMF-inoculated than in non-AMF-treated plants exposed to SMDS. Mycorrhizal plants recorded a significantly higher concentration of precursors of PA synthesis such as L-ornithine, agmatine, and -adenosyl methionine, besides higher putrescine and cadaverine and lower spermidine during the 15 days of SMDS. AMF colonization raised the PA synthase (arginine decarboxylase, ornithine decarboxylase, spermidine synthase, and spermine synthase) activities and PA-degrading enzymes (copper-containing diamine oxidase and FAD-containing polyamine oxidase) in response to SMDS. However, mycorrhizal plants showed a relatively lower degree of membrane lipid peroxidation, superoxide anion free radical, and hydrogen peroxide than non-mycorrhizal plants, whereas the difference between them increased linearly up to 15 days of SMDS. Our study concluded that AMF regulated PA homeostasis in roots of trifoliate orange to tolerate SMDS.
土壤丛枝菌根真菌（AMF）可增强植物对土壤水分亏缺胁迫（SMDS）的耐受性，但其潜在机制仍未完全明确。多胺（PAs）作为低分子量脂肪族聚阳离子，在植物非生物胁迫耐受性中发挥着重要作用。我们旨在研究接种AMF对经受15天SMDS的枳橙根系中多胺、多胺前体、多胺合成酶和降解酶活性以及活性氧浓度的影响。在经受SMDS的情况下，接种AMF的植株叶片水势和总叶绿素水平相比未接种AMF的植株更高。在15天的SMDS期间，菌根植株不仅腐胺和尸胺含量较高，亚精胺含量较低，而且多胺合成前体如L-鸟氨酸、胍丁胺和S-腺苷甲硫氨酸的浓度也显著更高。AMF定殖提高了响应SMDS的多胺合成酶（精氨酸脱羧酶、鸟氨酸脱羧酶、亚精胺合成酶和精胺合成酶）活性以及多胺降解酶（含铜二胺氧化酶和含FAD多胺氧化酶）活性。然而，菌根植株的膜脂过氧化程度、超氧阴离子自由基和过氧化氢含量相对低于非菌根植株，且在15天的SMDS期间，两者之间的差异呈线性增加。我们的研究得出结论，AMF通过调节枳橙根系中的多胺稳态来耐受SMDS。
