State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science , Chinese Academy of Sciences , No. 71, East Beijing Road , P.O. Box 821, Nanjing 210008 , China.
University of Chinese Academy of Sciences , Beijing 100049 , China.
J Agric Food Chem. 2018 Jul 18;66(28):7514-7521. doi: 10.1021/acs.jafc.8b01931. Epub 2018 Jul 10.
Humic acid (HA) has an inhibitory effect on phytopathogenic fungi, but the structure-activity relationship remains unclear. HAs were extracted from 14 different materials, and their fungistatic activities and elemental C, N, S, and O contents were measured. Cross-polarization magic-angle spinning C nuclear magnetic resonance (CPMAS C NMR) was used to measure the organic carbon composition. The results showed that all HAs suppressed phytopathogenic fungi growth, with Yunnan lignite HAs showing the highest inhibition (85.3%) against Physalospora piricola. The soil and compost HA aromaticity (ARO) was <50%, except for black soil HAs, while the ARO of all coal HAs was >60%. The ARO of meadow and moss peat HAs was <50%, while the ARO of woody peat HAs was 50.61%. Mantel test and redundancy analysis (RDA) were applied to evaluate the structure-activity relationship. The Mantel test revealed that the N, S, O, N/O, carbonyl C, aromatic C-O, and anomeric C contents were significantly correlated with fungistatic activity. The RDA analysis showed that the S content was positively correlated with fungistatic activity, while the O content was negatively correlated. The carbonyl C content had a positive correlation with fungistatic activity, while the anomeric C and aromatic C-O content had a negative correlation. A high S content and an active composition (carbonyl C) in HAs would lead to a high degree of fungistatic activity. Phytotoxicity test indicated all HAs were beneficial to plant growth. This work identified the basic properties of HAs from various raw materials that control their fungistatic activities.
腐殖酸（HA）对植物病原菌具有抑制作用，但结构-活性关系尚不清楚。从 14 种不同的材料中提取了 HA，并测量了它们的抑菌活性以及元素 C、N、S 和 O 的含量。交叉极化魔角旋转 C 核磁共振（CPMAS C NMR）用于测量有机碳组成。结果表明，所有 HA 均抑制了植物病原菌的生长，其中云南褐煤 HA 对 Physalospora piricola 的抑制率最高（85.3%）。土壤和堆肥 HA 的芳构度（ARO）<50%，除了黑土 HA 外，而所有煤 HA 的 ARO 均>60%。草地和苔藓泥炭 HA 的 ARO<50%，而木质泥炭 HA 的 ARO 为 50.61%。Mantel 检验和冗余分析（RDA）用于评估结构-活性关系。Mantel 检验表明，N、S、O、N/O、羰基 C、芳基 C-O 和端基 C 的含量与抑菌活性显著相关。RDA 分析表明，S 含量与抑菌活性呈正相关，而 O 含量呈负相关。羰基 C 含量与抑菌活性呈正相关，而端基 C 和芳基 C-O 含量与抑菌活性呈负相关。HA 中高 S 含量和活性成分（羰基 C）会导致高抑菌活性。植物毒性试验表明，所有 HA 均有利于植物生长。这项工作确定了控制其抑菌活性的各种原料 HA 的基本性质。
