Larena I, De Cal A, Melgarejo P
Department of Plant Protection, INIA, Carretera de La Coruña Km. 7, 28040 Madrid, Spain.
Int J Food Microbiol. 2004 Jul 15;94(2):161-7. doi: 10.1016/j.ijfoodmicro.2004.01.007.
Production of conidia of Epicoccum nigrum, a biocontrol agent of the fungal pathogen Monilinia laxa, was tested in liquid- and solid-state fermentation. Liquid fermentation was conducted in 250 ml Erlenmeyer flasks containing 50 ml of a mineral medium (containing per litre: 20 g lactose, 10 g NO3K, 1 g K2HPO4, 0.5 g MgSO4.7H2O, and 1 ml of a minor-element solution), inoculated with 2 x 10(5) E. nigrum conidia ml(-1), and incubated at 20-25 degrees C and 150 rpm for 7 days. Solid-state fermentation was carried out in specially designed plastic bags (600 cm3) (VALMIC) containing either 50 g of peat/vermiculite (1:1, w/w), or 50 g of peat/vermiculite/lentil meal (1:1:1, w/w/w) with 40% (v/w) initial moisture content. Substrate was inoculated with a conidial suspension of E. nigrum to give 10(5) conidia g(-1) substrate, and bags were incubated at 20-25 degrees C for 7 days in darkness. The amount of conidia of E. nigrum obtained in solid-state fermentation with substrate based on peat/vermiculite/lentil meal was 10-fold higher than with substrate based on peat/vermiculite or in liquid fermentation. Conidial production under these conditions was maintained in the range of 10(8) conidia g(-1) substrate from 10 to 150 days after inoculation. Germinability of these conidia was >90%. Addition of other nutrients than lentil meal to peat/vermiculite did not enhance production of conidia. Presence of peat in the substrate was necessary for good conidia production, but change in the kind of peat or vermiculite did not improve conidial production. Conidial production was similar when the substrate was inoculated with 10(5), 10(6) or 10(7) conidia g(-1) dry substrate. Incubation of bags in light conditions did not enhance conidial production. Fresh conidia produced in this solid-state fermentation system reduced the incidence and lesion diameter induced by M. laxa on peaches.
对作为真菌病原体核果褐腐病菌(Monilinia laxa)生物防治剂的黑附球菌(Epicoccum nigrum)分生孢子的生产进行了液态和固态发酵测试。液态发酵在装有50毫升矿物培养基(每升含有:20克乳糖、10克硝酸钾、1克磷酸氢二钾、0.5克七水硫酸镁和1毫升微量元素溶液)的250毫升锥形瓶中进行,接种2×10⁵个黑附球菌分生孢子/毫升,在20 - 25℃和150转/分钟下培养7天。固态发酵在特别设计的塑料袋(600立方厘米)(VALMIC)中进行,袋中装有50克泥炭/蛭石(1:1,重量比)或50克泥炭/蛭石/扁豆粉(1:1:1,重量比),初始含水量为40%(体积/重量)。用黑附球菌的分生孢子悬浮液接种底物,使底物中含有10⁵个分生孢子/克,袋子在20 - 25℃黑暗中培养7天。基于泥炭/蛭石/扁豆粉的底物进行固态发酵获得的黑附球菌分生孢子数量比基于泥炭/蛭石的底物或液态发酵高10倍。在接种后10至150天内,这些条件下的分生孢子产量维持在10⁸个分生孢子/克底物的范围内。这些分生孢子的发芽率>90%。向泥炭/蛭石中添加除扁豆粉之外的其他营养物质并不能提高分生孢子的产量。底物中泥炭的存在对于良好的分生孢子生产是必要的,但泥炭或蛭石种类的改变并不能改善分生孢子的生产。当用10⁵、10⁶或10⁷个分生孢子/克干底物接种底物时,分生孢子产量相似。在光照条件下培养袋子并不能提高分生孢子产量。在这种固态发酵系统中产生的新鲜分生孢子降低了核果褐腐病菌对桃子造成的发病率和病斑直径。