韭菜等几种植物根系分泌物对棉花黄萎病菌的影响

通过水培法收集韭菜、大葱、野薄荷、藿香和薰衣草的根系分泌物,研究其对大丽轮枝菌菌丝生长、孢子萌发的影响,并通过室内盆栽试验研究了植物根系分泌物对大丽轮枝菌微菌核萌发的影响。结果表明,5种植物根系分泌物对大丽轮枝菌菌丝生长和孢子萌发均表现为抑制作用;随着浓度的升高,抑制作用增强,而在同一浓度下,随着处理时间的延长,根系分泌物对孢子萌发的抑制作用逐渐减弱。盆栽试验表明,植物根系分泌物对大丽轮枝菌微菌核的萌发均表现为抑制作用,且微菌核对韭菜根系分泌物最为敏感。5种植物中,韭菜根系分泌物的抑制作用最强,野薄荷次之,藿香最弱。     

大蒜根系分泌物对烟草镰刀菌根腐病的控制作用

为探讨大蒜根系分泌物对烟草尖孢镰刀菌的抑菌活性,采用琼脂法培养大蒜,利用气相色谱—质谱技术（GC-MS）测定其主要成分,研究大蒜根系分泌物对烟草尖孢镰刀菌根腐病的影响。对菌丝生长速率和孢子萌发的测定表明,当大蒜根系分泌物粗提物浓度为1 g/mL时,其菌丝生长抑制率为30.56%,孢子萌发抑制率高达100.00%。大蒜根系分泌物主要成份2,6—二异丙基苯酚和邻苯二甲酸二丁酯分别对其菌丝生长和孢子萌发具有较强的抑菌作用。邻苯二甲酸二丁酯的防控效果较好,其浓度为5 mmol/L,接菌21 d后其病情指数为55.00,防控效果达32.38%。大蒜根系分泌物及主要成分对尖孢镰刀菌所引起的烟草根腐病有显著的抑制作用,这为研制含大蒜成分的植物保护剂和间作套种大蒜防控烟草尖孢镰刀菌根腐病提供科学参考。     

棉花不同抗性品种根系分泌物分析及其对黄萎病菌的影响

 对7个不同抗黄萎病性能的棉花品种根系分泌物进行了收集和测定,结果发现抗病品种根系分泌物对病菌的孢子萌发和菌丝生长有一定的抑制作用,而感病品种根系分泌物则能刺激病菌生长。感病品种分泌物中氨基酸含量和种类较多,而且苯丙氨酸、脯氨酸等仅出现在感病品种的分泌物中;抗病品种根系分泌物中糖类物质含量亦明显低于感病品种。     

野生抗病茄植株腐解物对茄子黄萎病的调控研究

以4种野生抗病茄为试材,通过生长速率法和悬滴法测试了其根、茎、叶腐解物的乙醇提取液对茄子黄萎病菌菌丝生长和分生孢子萌发的室内抑制作用,并对室内抑菌效果较好的处理进行了盆栽防病试验。供试腐解物提取液对茄子黄萎病菌均具有一定抑制作用。其中,叶对菌丝生长的抑制率最高(>30%),抑制作用顺序为刚果茄>托鲁巴姆>CRP(刺茄)>赤茄,对孢子萌发的抑制效果较好的是刚果茄叶>CRP叶>刚果茄茎>赤茄叶>托鲁巴姆叶(>77%)。盆栽试验表明,除赤茄叶片腐解物外,其他3种野生茄叶片腐解物对茄子黄萎病均具有治疗效果;4种野生茄叶片腐解物对茄子黄萎病的预防效果均较好。     

不同浓度苦参提取物对蔬菜病原菌的抑菌活性

采用生长速率法和悬滴法室内测试了不同浓度苦参提取物对葱菌核菌、番茄早疫菌、菜豆根腐菌、辣椒枯萎菌、黄瓜枯萎菌、茄子黄萎菌等6种蔬菜病原菌的抑菌活性。结果表明:苦参提取物对供试病菌菌丝生长和孢子萌发均有很强的抑制作用。在供试质量浓度10mg/mL时,对辣椒枯萎菌、葱菌核菌、菜豆根腐菌、黄瓜枯萎菌菌丝生长的抑制率均在61%以上;在供试质量浓度30mg/mL时,对辣椒枯萎菌、菜豆根腐菌、黄瓜枯萎菌、番茄早疫菌的抑制率均在70%以上,对葱菌核菌的抑制率达81.61%。试验表明,随着苦参提取液浓度的升高对供试菌孢子萌发抑制作用增强。在供试质量浓度30mg/mL时,孢子萌发抑制率均在77.04%以上。     

玉米根系分泌物对烟草黑胫病菌的抑制活性及其抑菌物质分析

本文研究了玉米根系与烟草疫霉菌游动孢子的互作及玉米根系分泌物对烟草疫霉菌各个生育阶段的抑菌活性,并利用HPLC-MS分析了根系分泌物中具有抑菌活性的物质。结果表明,玉米根系能吸引烟草疫霉菌游动孢子,其分泌物也能使孢子休止并裂解。进一步研究表明,玉米根系分泌物对烟草疫霉菌游动孢子的释放、休止孢萌发及菌丝生长均具有明显的抑制活性,在浓度0.90 mg/m L时抑制率分别为73.8%、87.2%和55.2%。HPLC-MS分析结果表明,根系分泌物中存在苯并嗪类化合物丁布及其降解产物门布,其中门布对烟草疫霉菌菌丝的生长具有明显的抑菌活性,浓度0.30 mg/m L时抑制率达90.94%。综上所述,玉米根系既能吸引游动孢子,又能分泌对烟草疫霉菌具有抑制活性的苯并嗪类化合物。该结果对合理利用玉米与烤烟轮作控制烟草黑胫病的发生具有重要意义。     

农药对虫生真菌粉虱座壳孢孢子萌发和菌丝生长的影响

虫生真菌粉虱座壳孢Aschersonia aleyrodis是大有前途的粉虱和介壳虫杀虫剂。用6种大田常用农药在推荐浓度下，研究其在25℃下对座壳孢菌孢子萌发和菌丝生长的影响，发现甲氰菊酯和克螨特抑制其孢子萌发和菌丝生长，表明二者与本菌极不相容。吡虫啉、水胺硫磷和双甲脒能促进孢子萌发且后两者亦可加速菌丝生长，多菌灵对其孢子萌发起暂时促进作用然而抑制其菌丝生长。     

丁香精油及其与壳聚糖复合物对水果采后病原菌的抑制作用

研究了丁香精油以及丁香精油-壳聚糖复合物对几种水果采后腐烂的主要致病真菌灰霉菌、链格孢,青霉菌、浆孢菌的孢子萌发和菌丝生长的抑制效应,确定其最低抑菌浓度和最低杀菌浓度。结果表明,丁香精油对供试病原菌均有较强的抑制效果,10μL/mL丁香油对4种菌菌丝生长和孢子萌发的抑制率达到85%以上。丁香油-壳聚糖复合物溶液在10μL/mL时(含丁香油有效成分5μL/mL)对4种菌菌丝生长和孢子萌发的抑制率在80%以上,而5μL/mL丁香油对其菌丝生长和孢子萌发的抑制率大都在80%以下,复合物的抑菌效应比含有相同有效浓度的丁香精油抑菌效应有明显提高。     

ZJUF0986活性代谢产物对稻瘟病菌致病性的影响

通过菌丝生长速率法和悬滴法测定ZJUF0986活性代谢产物对稻瘟病菌菌丝生长、孢子萌发和附着胞形成的影响。结果表明,ZJUF0986活性代谢产物对稻瘟病菌菌丝生长的有效中浓度EC50为18.55mg/L,与对照药剂三环唑的EC50(17.30mg/L)相比无显著性差异。活性代谢产物不仅影响孢子萌发,也显著降低附着胞的形成。浓度为10mg/L的活性代谢物可完全抑制孢子萌发及附着胞的形成;浓度为1.25mg/L时则明显延缓孢子萌发及附着胞的形成,处理48h后的孢子萌发率和附着胞形成率分别为62.17%和38.46%。以浓度为1.25mg/L活性代谢产物处理的稻瘟病菌孢子悬浮液接种离体大麦叶片,病原菌孢子在大麦叶片表面能部分萌发形成附着胞,但侵染栓形成延迟,致病性明显降低。     

海洋霉菌1-B6-10代谢产物对几种镰刀菌的抑制作用

测试了海洋霉菌菌株1-B6-10代谢产物对不同镰刀菌菌丝生长、孢子萌发和显微形态的影响.结果表明,该菌代谢产物粗提物对尖孢镰刀菌Fusarium oxysporum菌株F1113、F1125和番茄镰刀菌Fusarium batatasis菌株F2016等的菌丝生长具有明显的抑制作用.当纸片上滴加0.05 mL该粗提物时,其抑菌圈直径均在32 mm以上;在菌株F1125菌丝块上直接滴加0.05 mL该粗提物,其菌丝生长抑制率达到98.39%.该代谢产物也能显著抑制尖孢镰刀菌F113和F1125孢子的萌发,用粗提物处理后培养48h,其孢子萌发率仅为8%和9.6%.显微镜观察结果表明,在添加该代谢产物亚抑菌浓度的培养基中,尖孢镰刀菌F1113菌丝的形态发生改变,部分菌丝萎缩和断裂.     

Root exudates associated with the resistance of four chickpea cultivars (Cicer arietinum) to two races of Fusarium oxysporum f.sp. ciceri

The germination of race 1 spores of Fusarium oxysporum f. sp. ciceri was significantly inhibited by the root exudate of the wilt-resistant chickpea cvs CPS1 and WR315 compared to untreated spores and spores treated with root exudates from susceptible cultivars. The effect was concentration dependent, such that the exudate from 1 g of root in 2 ml of water almost completely inhibited spore germination, whereas the exudate from 1 g of root in 20 ml water did not do so. The inhibitory effects of the active exudates were negated when the apolar components of the exudates were removed by extraction with ethyl acetate. The root exudates of the susceptible cv. JG62 and the late wilting cv. H208 did not inhibit germination. The hyphal growth of germinated spores was also strongly inhibited by the concentrated exudates of CPS1 and WR315, and diluted exudates were less potent. The highest concentration of the exudate of the susceptible cv. JG62 showed some inhibition of hyphal growth, whereas none of the exudates of H208 were found to contain any antifungal activity. The effect of the exudates on the spores of race 2 was similar to that reported for race 1, except that the water-soluble components of the crude root exudate of WR315 after ethyl acetate extraction were also found to inhibit germination significantly. Overall, the spores of race 2 appeared to be more susceptible to the effects of the exudates. The ethyl acetate fractions of the root exudates of CPS1 and WR315 strongly inhibited germination and hyphal growth of both race 1 and race 2, the effect being concentration dependent. The results suggest that the resistance of chickpeas to vascular wilt depends, at least in part, upon the antifungal activity of the root exudates. Differences in the expression of resistance in the field could depend upon the concentration or rate of production of constitutive antifungal components by the root.     

Pisatin involvement in the variation of inhibition of Fusarium oxysporum f. sp. pisi spore germination by root exudates of Pisum spp. germplasm

Fusarium wilt caused by Fusarium oxysporum f. sp. pisi (Fop) is one of the major constraints of pea worldwide. Its control is difficult and is mainly based on the use of resistant cultivars. This study aimed to identify and characterize resistance mechanisms interfering with Fop spore germination, as an additional pre‐penetration resistance mechanism little explored so far. For this, root exudates were collected from 12 pea accessions with differential responses to the disease, from resistant to susceptible, and their effects on Fop germination and growth were determined. While root exudates from most accessions stimulated Fop germination, the root exudates of three accessions, JI 1412, JI 2480 and P42, did not stimulate, or even inhibited, Fop germination. Although some additional compounds might be involved, the analysis showed that the most active metabolite was the pea phytoalexin pisatin. Pisatin was identified in the active fraction of pea root exudate extracts and its amount in the root exudates was negatively correlated with the extent of Fop germination. This suggests an important role of pisatin in the constitutive defence of pea against F. oxysporum.     

苦瓜枯萎病菌的生物学特性研究

对尖镰孢苦瓜专化型(Fusarium oxysporumf.sp.momdicae Sun &; Huang)的生物学特性进行研究。结果表明,苦瓜枯萎病孢子在蒸馏水中萌发率仅为5%左右,在葡萄糖、蔗糖等溶液中提高到19%,而在苦瓜植株煎汁中可达到96%～100%,这说明孢子萌发,营养条件是主要因素。菌丝生长的最适温度为28～30℃,产孢的最适温度为28℃。该菌在pH2.3～11.3的范围内都能生长,最适pH6.3。全光照条件下生长最好,全黑暗的条件下长得最慢。菌丝生长最适碳源是可溶性淀粉,最适氮源是蛋白胨。     

杭白菊枯萎病的病原菌分离鉴定及淀粉酶产色链霉菌对其防治效果

杭白菊枯萎病是杭白菊重要病害之一,枯萎病的爆发对杭白菊产量造成了巨大的影响。为了明确杭白菊枯萎病的病原菌及其生防菌的防治效果,本文通过形态学和ITS序列分析方法,初步鉴定杭白菊枯萎病病原菌为半裸镰刀菌Fusarium incarnatum。进一步采用菌丝生长速率法和孢子萌发法,测定了淀粉酶产色链霉菌Streptomyces diastatochramogenes 1628代谢产物对该病原菌的抑制效果。结果发现,链霉菌1628代谢产物对菌丝生长和孢子萌发的EC₅₀分别为2.22%和4.70%（体积浓度）。盆栽试验结果表明,施用淀粉酶产色链霉菌代谢产物原液14和28 d后,其对杭白菊枯萎病的保护效果、治疗效果分别为52.84%和42.85%、19.23%和30.16%。说明淀粉酶产色链霉菌1628的代谢产物对杭白菊枯萎病具有明显的保护和治疗作用。     

Interaction betweenSclerotinia sclerotiorum andConiothyrium minitans strains with different aggressiveness

The effects ofSclerotinia sclerotiorum live and autoclaved sclerotia, and sclerotial exudates, and commercial oxalic acid were testedin vitro on sevenConiothyrium minitans strains differing in aggressiveness towardsS. sclerotiorum. Only sclerotial exudates and autoclaved sclerotia affected the mycelial growth rate of almost all the strains tested, whereas a change in theC. minitans mycelial growth pattern was observed in the presence of autoclaved sclerotia and live sclerotia germinating by the myceliogenic eruptive germination. In addition, sclerotial exudates had a stimulatory effect on spore germination. These findings indicate that the various treatments could influence theC. minitans strains regardless of their aggressiveness.     

The use of GFP<Emphasis Type="Italic">-</Emphasis>transformed isolates to study infection of banana with <Emphasis Type="Italic">Fusarium oxysporum</Emphasis> f. sp. <Emphasis Type="Italic">cubense</Emphasis> race 4

Fusarium oxysporum f. sp. cubense (Foc) is the causal pathogen of Fusarium wilt of banana. To understand infection of banana roots by Foc race 4, we developed a green fluorescent protein (GFP)-tagged transformant and studied pathogenesis using fluorescence microscopy and confocal laser scanning microscopy. The transformation was efficient, and GFP expression was stable for at least six subcultures with fluorescence clearly visible in both hyphae and spores. The transformed Foc isolate also retained its pathogenicity and growth pattern, which was similar to that of the wild type. The study showed that: (i) Foc race 4 was capable of invading the epidermal cells of banana roots directly; (ii) potential invasion sites include epidermal cells of root caps and elongation zone, and natural wounds in the lateral root base; (iii) in banana roots, fungal hyphae were able to penetrate cell walls directly to grow inside and outside cells; and (iv) fungal spores were produced in the root system and rhizome. To better understand the interaction between Foc race 4 and bananas, nine banana cultivars were inoculated with the GFP-transformed pathogen. Root exudates from these cultivars were collected and their effect on conidia of the GFP-tagged Foc race 4 was determined. Our results showed that roots of the Foc race 4-susceptible banana plants were well colonized with the pathogen, but not those of the Foc race 4-resistant cultivars. Root exudates from highly resistant cultivars inhibited the germination and growth of the Fusarium wilt pathogen; those of moderately resistant cultivars reduced spore germination and hyphal growth, whereas the susceptible cultivars did not affect fungal germination and growth. The results of this work demonstrated that GFP-tagged Foc race 4 isolates are an effective tool to study plant–fungus interactions that could potentially be used for evaluating resistance in banana to Foc race 4 by means of root colonization studies. Banana root exudates could potentially also be used to identify cultivars in the Chinese Banana Germplasm Collection with resistance to the Fusarium wilt pathogen.     

防治牡丹根腐病的有效药剂筛选

采用菌丝生长速率法和孢子萌发法,分别测定了咪鲜胺、醚菌酯、苯醚甲环唑、百菌清、多菌灵、代森锰锌等6种杀菌剂对牡丹根腐病菌的室内毒力。结果表明,6种药剂对病菌菌丝生长的EC50大小顺序为：咪鲜胺<多菌灵<代森锰锌<苯醚甲环唑<百菌清<醚菌酯,其中以咪鲜胺对牡丹根腐病病菌的菌丝生长抑制作用最强, EC50为0.200 mg/L;多菌灵、代森锰锌、苯醚甲环唑、百菌清依次减弱,醚菌酯的抑制菌丝生长的作用最小,EC50为33.98 mg/L。6种药剂对病菌孢子萌发的EC50大小顺序为：百菌清<咪鲜胺<苯醚甲环唑<多菌灵<代森锰锌<醚菌酯;其中以百菌清对牡丹根腐病菌的孢子萌发抑制作用最强,EC50为0.343 mg/L;咪鲜胺、苯醚甲环唑、多菌灵、代森锰锌依次减弱,醚菌酯抑制孢子萌发的作用最小,EC50为38.4 mg/L。