草业学报2024，Vol.33Issue(7)：130-141,12.DOI:10.11686/cyxb2023316
尖孢镰刀菌苜蓿专化型厚垣孢子的诱导形成方法及萌发特性
Induced formation method and germination characteristics of chlamydospores by Fusarium oxysporum f.sp.medicaginis
摘要
Abstract
Chlamydospores are the main survival structure of Fusarium oxysporum in soil,and the number and germination status of chlamydospores in soil directly affects the occurrence and severity of the disease. In this study,we established a system to induce chlamydospore production by F. oxysporum f. sp. medicaginis (Fom) by culturing the pathogen on synthetic low nutrient agar (SNA) medium,synthetic low nutrient agar with filter (SNAF) medium,or in two-salt solution (KH2PO4 and MgSO4·7H2O) with glucose or magnesium carbonate at a range of concentrations. The chlamydospore induction system was verified,and the effects of different carbon and nitrogen sources on chlamydospore germination were studied. The T6 and T9 strains of Fom produced many chlamydospores after static culture for 7 days in the two-salt solution with glucose at 2 mg·L-1,producing 4.2×105 and 5.1×105 chlamydospores per mL,respectively. Both T6 and T9 produced more chlamydospores under static culture than under shaking culture (4.2-and 2.8-times,respectively,at 7 days of culture). All Fom strains produced many chlamydospores after 7 days of culture in the two-salt solution,with a rapid increase of 2.3-times compared with 3 days,followed by slow increases at 14 and 21 days,with an average increase of only 1.2-times from 7 to 21 days of culture. Comparing all the carbon and nitrogen sources,glucose and ammonium chloride had the strongest promoting effects on the germination and germ tube growth of chlamydospores,whereas lactose and urea had the weakest effects. The results show that chlamydospore formation by Fom strains requires a trace amount of a carbon source and a low-oxygen environment,and the germination and growth of chlamydospores require suitable carbon and nitrogen sources. These findings provide new insights into effective management of soil-borne diseases in alfalfa through controlling the primary infection source,i.e.,the chlamydospores of the pathogen.关键词
尖孢镰刀菌/土传病原真菌/存活结构/初侵染源/厚垣孢子Key words
Fusarium oxysporum/soilborne fungal pathogen/survival structure/primary inoculum/chlamydospore引用本文复制引用
方香玲,许世洋,南志标..尖孢镰刀菌苜蓿专化型厚垣孢子的诱导形成方法及萌发特性[J].草业学报,2024,33(7):130-141,12.基金项目
国家重点研发计划项目(2022YFD1300802),国家自然科学基金项目(32171678)和中美国际合作项目(32161123002)资助. （2022YFD1300802）
