LR21AGR03- Production and Protection for a Sustainable Horticulture (2PHD), Regional Research Centre On Horticulture and Organic Agriculture, University of Sousse, 4042, Chott-Mariem, Tunisia.
LR14AGR01, Laboratory of Genetics and Cereal Breeding, National Agronomic Institute of Tunisia, University of Carthage, Avenue Charles Nicolle 43, 1082, Tunis, Tunisia.
Braz J Microbiol. 2023 Jun;54(2):1103-1113. doi: 10.1007/s42770-023-00925-3. Epub 2023 Feb 20.
During storage, infected potato tubers by Fusarium species leads to significant losses. Searching natural-based alternatives to chemical fungicides for the control of tuber dry rot pathogens is becoming essential. Nine Aspergillus spp. (A. niger, A. terreus, A. flavus, and Aspergillus sp.) isolates, recovered from soil and compost samples, were explored and evaluated for their ability to suppress Fusarium sambucinum the main causal agent of potato tuber dry rot disease in Tunisia. All conidial suspensions of Aspergillus spp. tested and their cell-free culture filtrates had significantly inhibited the in vitro pathogen growth by 18.5 to 35.9% and by 9 to 69% compared to control, respectively. A. niger CH12 cell-free filtrate was the most active against F. sambucinum at the three concentration tested (10, 15, and 20% v v). Chloroform and ethyl acetate extracts from four Aspergillus spp., tested at 5% v v, had limited F. sambucinum mycelial growth by 34-60% and 38-66%, respectively, compared to control, with A. niger CH12 ethyl extract being the most active. Tested on potato tubers inoculated with F. sambucinum, all tested Aspergillus spp. isolates, their cell-free filtrates and organic extracts had significantly decreased the external diameter of dry rot lesion compared to pathogen-inoculated and untreated control tubers. For the rot penetration, all Aspergillus spp. isolates, their organic extracts and only filtrates from A. niger CH12 and MC2 isolates had significantly limited dry rot severity compared to pathogen-inoculated and untreated control. The highest reductions in the external diameter of dry rot lesion (76.6 and 64.1%) and the average rot penetration (77.1 and 65.1%) were achieved using chloroform and ethyl acetate extracts from A. niger CH12, respectively. These results clearly demonstrated the presence of bioactive compounds in Aspergillus spp. that can be extracted and explored as an eco-friendly alternative for the control of the target pathogen.
在储存过程中，受镰刀菌属（Fusarium species）感染的土豆块茎会导致严重损失。因此，寻找替代化学杀菌剂的天然替代品来控制块茎干腐病病原菌变得至关重要。从土壤和堆肥样本中分离出的 9 种曲霉属（Aspergillus spp.）（黑曲霉、土曲霉、黄曲霉和曲霉属）菌株，对其抑制突尼斯土豆块茎干腐病主要病原体镰刀菌属（Fusarium sambucinum）的能力进行了探索和评估。所有测试的曲霉属（Aspergillus spp.）的分生孢子悬浮液及其无细胞培养滤液均显著抑制了病原菌的体外生长，抑制率分别为 18.5%至 35.9%和 9%至 69%。在三个测试浓度（10%、15%和 20%v/v）下，黑曲霉 CH12 的无细胞滤液对 F. sambucinum 的抑制作用最明显。在 5%v/v 下测试的四种曲霉属（Aspergillus spp.）的氯仿和乙酸乙酯提取物对 F. sambucinum 的菌丝生长分别有 34-60%和 38-66%的有限抑制作用，其中黑曲霉 CH12 的乙酸乙酯提取物活性最高。在接种了 F. sambucinum 的土豆块茎上进行测试时，所有测试的曲霉属（Aspergillus spp.）分离株、它们的无细胞滤液和有机提取物均显著降低了与病原菌接种和未处理对照块茎相比的干腐病病变的外径。对于腐烂的穿透性，所有的曲霉属（Aspergillus spp.）分离株、它们的有机提取物以及仅来自黑曲霉 CH12 和 MC2 分离株的滤液都显著限制了与病原菌接种和未处理对照相比的干腐病严重程度。使用黑曲霉 CH12 的氯仿和乙酸乙酯提取物分别获得了干腐病病变外径的最高降低（76.6%和 64.1%）和平均腐烂穿透（77.1%和 65.1%）。这些结果清楚地表明，曲霉属（Aspergillus spp.）中存在具有生物活性的化合物，可以作为控制目标病原菌的环保替代品进行提取和探索。
