茶树油粕粗提物对柑橘青绿霉病发生的抑制作用

首先用乙醇提取得到茶树油粕粗提物,研究了粗提物对柑橘青霉和绿霉病原菌离体生长和活体致病的防控效果。离体抑菌试验表明,茶树油粕粗提物可显著抑制离体培养的青霉和绿霉病菌的生长,当提取物浓度为10 mg/m L以上时,对青霉菌和绿霉菌菌落生长的抑制率分别达100%和70%,而相同浓度茶皂素的抑制率仅有30%和58%;活体接种试验表明,茶树油粕粗提物可明显抑制青霉病病斑的扩展和贮藏过程中果实的发病率,而茶皂素对病斑扩展和果实发病率的控制没有明显作用。同未处理对照相比,50 mg/m L的粗提物对青霉病病斑扩展的抑制率达60%以上,将柠檬和砂糖橘果实贮藏过程中的发病率降低了25%~58%,而对果实的品质没有明显影响。本研究表明,茶树油粕粗提物对柑橘青绿霉病菌的离体和活体抑制效果显著优于茶皂素,暗示粗提物中含有除茶皂素之外的活性抑菌组分,有望开发成为防控柑橘采后病害的环境友好型的新型保鲜剂组分。     

柑橘内生燕麦镰刀菌Gds-1对柑橘青霉病的防治研究

柑橘青霉病是柑橘果实采后危害最大的病害。为得到一株可有效应用于柑橘青霉病防治的柑橘内生真菌菌株，进行了柑橘果实内生菌分离、离体与活体试验筛选、菌株形态学与多基因位点分子系统发育鉴定、菌株活体应用效果与作用特点以及菌株代谢产物稳定性与应用防效试验。结果表明:筛选所得的柑橘内生真菌Gds-1在离体与活体条件下均对柑橘青霉菌有较好的抑制效果；经多基因位点联合系统发育分析，将Gds-1鉴定为燕麦镰刀菌Fusarium avenaceum；提前48 h施用Gds-1菌体，对柑橘青霉病的预防效果最好 (防治效果为90.67%)；Gds-1菌丝不会损害健康柑橘果实表皮，但可以在柑橘果实表皮伤口和被柑橘青霉菌感染的组织部位发挥作用，从而抑制柑橘青霉菌；当温度在 ?80~100 ℃和pH=5~10时，Gds-1无菌发酵液对柑橘青霉菌的拮抗作用高效稳定；单独施用Gds-1无菌发酵滤液28 d和56 d时，对柑橘青霉病的防效与100 μg/mL的抑霉唑相当，显著高于清水对照。本研究首次报道了生防镰刀菌F. avenaceum Gds-1对柑橘青霉病的防治作用，为柑橘果实采后生物源防腐剂的选择提供了新来源，为镰刀菌生物防治机理研究提供了新思路。     

建兰炭疽病拮抗放线菌的筛选及防治效果

为筛选获得对建兰炭疽病菌胶孢炭疽菌具有良好抑菌效果的放线菌，以野生山地兰花表层土壤为分离样本，从土壤样品中分离获得25株放线菌，初筛出6株对建兰炭疽病菌胶孢炭疽菌具有明显抑制作用的菌株，其中菌株SVFJ-07的抑菌效果最好，抑菌率达83.64%。经形态特征、生理生化特征及16S rDNA序列分析，确认菌株SVFJ-07为酒红链霉菌。该菌对多种真菌具有良好的抑菌效果。对建兰炭疽病的室内防效为70.06%，田间防效66.27%～68.54%。可见，酒红链霉菌SVFJ-07对建兰炭疽病菌胶孢炭疽菌具有较好的拮抗作用，生防应用前景良好。     

生防细菌C-4的特性鉴定及其对香蕉枯萎病的防治效果

采用平板对峙法从香蕉根际土壤中共分离到74株细菌,其中菌株C-4对香蕉枯萎病菌1号小种和4号小种均有强抑制作用,相对抑制率分别为81.25%和83.75%。抑菌谱测定结果表明,菌株C-4具有较广的抑菌范围,对番茄枯萎病菌、玉米弯孢叶斑病菌、胶孢炭疽病菌、棉花枯萎病菌、棉花黄萎病菌、小麦赤霉病菌和西瓜枯萎病菌等均有抑制作用。根据Biolog系统鉴定及16S rDNA序列分析结果,将菌株C-4鉴定为地衣芽孢杆菌Bacillus licheniformis,其在YPGA或PDA培养基、32~35℃、pH 7.8~8.0、40~52h培养条件下生长和拮抗作用最为理想。室内盆栽试验结果显示,菌株C-4对香蕉枯萎病具有良好的防效,接种30天后病情指数明显低于对照。     

胶孢炭疽菌生防放线菌gz-8的鉴定及生物活性初步评价

从山东省临沂地区土壤中分离到一株放线菌gz-8,发现其对胶孢炭疽菌Colletotrichum gloeosporioides具有较强的抑制作用,皿内抑菌活性达72.5%。通过形态特征和生理生化测定,结合16S rDNA序列分析,鉴定该菌株为栗褐链霉菌Streptomyces badius。抗菌谱测定结果表明,菌株gz-8对6种植物病原真菌均具有较强的抑菌活性,抗菌谱较广。进一步对菌株gz-8的粗提物进行了生物活性评价,发现其发酵液粗提物可以明显抑制胶孢炭疽菌的菌丝生长（EC50=3.18 μg/mL）和分生孢子萌发（IC50=1.92 μg/mL）,且活性明显高于菌体粗提物;同时发酵液粗提物具有良好的热稳定性及pH稳定性;1 000 mg/L的发酵液粗提物对感染胶孢炭疽病芒果果实的防效达到35.94%,与同浓度下百菌清的防效（34.11%）无显著差异。     

十字花科根肿病生防菌副地衣芽胞杆菌ZF480的鉴定及其防效

为有效防控十字花科蔬菜生产中的毁灭性病害——根肿病,以尖孢镰孢菌Fusarium oxysporum和辣椒疫霉Phytophthora capsici为指示菌,利用平板对峙法对分离自土壤的1 198株细菌进行筛选,进通过盆栽试验筛选对十字花科根肿病具有良好防效的生防菌株,并基于形态学特征、生理生化特性及16S rDNA、gyrB和atpD多基因系统发育分析对生防菌株进行鉴定,同时测定其抑菌谱和田间防效。结果表明,通过对峙培养筛选获得115株有抑菌效果的生防菌株,采用盆栽试验获得1株对根肿病菌具有拮抗效果的菌株,命名为ZF480。结合形态学特征和系统发育分析结果将该菌株鉴定为副地衣芽胞杆菌Bacillus paralicheniformis。菌株ZF480对野油菜黄单胞野油菜变种Xanthomonas campestris pv. campestris等10种病原菌具有拮抗效果,抑菌谱较宽,对白菜根肿病的盆栽防效和田间防效分别达到72.82%和64.08%。表明副地衣芽胞杆菌菌株ZF480对十字花科根肿病具有显著的防效,可作为生防菌进一步开发利用。     

链霉菌XG40的鉴定及其对琯溪蜜柚黑斑病的防效

为筛选出对琯溪蜜柚黑斑病菌有拮抗效果的生防菌株,本研究采用平板对峙法和牛津杯法分离筛选植物根际土壤放线菌,共分离纯化得到12株能够拮抗蜜柚黑斑病菌Phyllosticta citriasiana的放线菌菌株,其中菌株XG40对蜜柚黑斑病菌的拮抗能力最强,抑菌带宽度为16.3 mm。根据形态特征、生理生化特征以及16S rDNA、recA、rpoB、gyrB序列分析,将菌株XG40确定为小串链霉菌Streptomyces catenulae。抗菌谱试验结果表明,菌株XG40的发酵液对番茄叶霉病菌、蜜柚炭疽病菌、蜜柚黑点病菌等12种植物病原真菌和2种植物病原细菌也有较好的拮抗作用,抗菌性能广谱高效。菌株XG40对黑斑病菌的抑菌机制表现为受抑制菌丝发生畸变、粗细不均匀、大量断裂,其发酵液能使黑斑病菌孢子内含物消解并产生液泡。防效测定结果表明,菌株XG40发酵液对室内离体果实黑斑病的预防效果和治疗效果分别为83.52%和78.87%;对田间果实黑斑病的预防效果和治疗效果分别为78.91%和71.15%。因此,菌株XG40可作为防治蜜柚黑斑病的生防材料,具有良好的开发价值和应用前景。     

一种油茶新炭疽病原的多基因系统发育分析鉴定

为明确我国油茶炭疽病病原菌的种类,对采集自我国6个省市油茶产区的炭疽病样本进行病原菌分离,通过形态学特征并结合多基因谱系分析方法构建系统发育树进行比较分析.结果表明共分离到能引起油茶叶出现炭疽病症状的病原菌23株.病原菌在PDA培养基上28 ℃培养7 d后,菌落圆形,初期白色,逐渐变为灰色,最终为灰黑色;分生孢子堆橘黄色,分生孢子椭圆形、单胞、无色,大小为(16.8±0.7) μm×(5.7±0.4) μm;菌丝附着孢椭圆形,褐色,边缘光滑、完整,大小为(9.5±1.5) μm×(6.1±0.6) μm.多基因系统发育树显示,这23株病原菌与包括模式菌株ICMP 18581在内的所有果生刺盘孢菌Colletotrichum fructicola菌株序列聚为一个进化枝,置信度高达100%.根据形态特征及多基因系统发育树,鉴定这23株病原菌为果生刺盘孢菌C.fructicola,为国内油茶上果生刺盘孢菌的首次报道.     

油菜菌核病内生拮抗细菌的筛选及防病作用研究

以油菜菌核病菌Sclerotinia sclerotiorum为靶标菌,测定了63株内生细菌对其菌丝生长、菌核形成及萌发的抑制作用。结果表明:在所有供试菌株中,除1株未表现出抑菌活性外,其余菌株均有抑菌作用,其中有6.3％的菌株抑菌带大于10 mm,7株细菌可完全抑制病原菌的菌核形成,1株细菌可完全抑制菌核萌发;此外,结合生物测定结果,从中筛选到1株对油菜菌核病的高效生防菌株Em7,其无菌培养滤液对温室苗期油菜菌核病的防治效果可达97.5％。通过形态特征、生理生化特性及16S rDNA序列分析,认为该菌株属于枯草芽孢杆菌Bacillus subtilis。于接种病菌前后不同时间喷施菌株Em7无菌培养滤液,对油菜菌核病均有防治效果,但防效之间差异显著,以接种病菌前24 h喷施防效最高。原液及不同稀释度无菌培养滤液对菌丝生长、菌核萌发及病害防治的效果明显不同,随着稀释度的增加,其抑菌效果降低。显微观察结果表明,菌株Em7对油菜菌核病菌菌丝的生长与发育会产生明显影响,可致使菌丝畸形、皱缩及细胞质外渗。     

嘧霉胺对采后柑橘绿霉病的防治效果

在实验室和贮藏库条件下,对嘧霉胺单剂、嘧霉胺与抑霉唑或嘧霉胺和咪鲜胺混剂防治柑橘绿霉病的效果进行了评价。室内实验结果表明:采用500或1 000 mg/L嘧霉胺单剂、500 mg/L嘧霉胺+500 mg/L抑霉唑或500 mg/L嘧霉胺+500 mg/L咪鲜胺混剂在接种后12~18 h进行浸果处理,对由抑霉唑抗性或敏感菌株引起的绿霉病均有显著的防治效果,防效超过94%;500或1 000 mg/L 的抑霉唑对敏感菌株的防效在93%以上,但对抗性菌株的防效低于70%。贮藏库防效试验结果表明:在具抑霉唑抗性菌系的贮藏库中,上述质量浓度的嘧霉胺单剂、嘧霉胺与抑霉唑、或嘧霉胺与咪鲜胺混剂对绿霉病的防治效果明显优于抑霉唑单剂;而在不具抗抑霉唑菌系贮藏库中的防效则与抑霉唑相当。由此认为:嘧霉胺可作为抑霉唑的替代药剂应用于柑橘的采后处理,其推荐使用质量浓度为500~1 000 mg/L,可单独使用,也可与抑霉唑或咪鲜胺混合使用。     

菌株BM-24的分离鉴定及对香蕉枯萎病菌的抑菌活性

为了从饼肥发酵液中分离筛选出对香蕉枯萎病菌Fusarium oxysporum f.sp.cubense有良好拮抗效果的菌株,以香蕉枯萎病病原菌为指示菌进行拮抗菌分离筛选.筛选得到29株拮抗菌,其中分离自菜子饼的菌株BM-24拮抗效果最显著.利用平板对峙法测定菌株BM-24抑菌谱,根据形态特征、培养特征及生理生化特征和16S rDNA序列分析对其进行鉴定,并测定其发酵液不同处理的抑菌活性.经鉴定,此菌株为甲基营养型芽胞杆菌Bacillus methylotrophicus,该菌株对供试的12种植物病原真菌均有很强的抑制作用,尤其对香蕉枯萎病菌1号和4号小种菌丝生长抑制作用最强,抑菌率分别达到87.2％和80.4％,其发酵液对香蕉枯萎病菌具有很强抑菌效果,抑菌活性主要源于菌体竞争.     

短短芽胞杆菌对植物病原真菌的抑菌活性和抑菌机理

为探讨短短芽胞杆菌菌株011对植物病原真菌的防控效果,采用平皿打孔法测定菌株011粗提液对14种植物病原真菌的抑制作用,并以番茄早疫病为研究对象,研究了其抑菌机理。结果显示,菌株011粗提液对14种病原真菌均有抑菌活性,其中对番茄早疫病菌的抑菌活性最强,抑菌率达45.9%;菌株011粗提液能导致番茄早疫病菌菌丝生长异常,抑制孢子萌发;对番茄早疫病菌菌丝生长的EC50为71.4 mg/m L,对孢子萌发的EC50和MIC分别为0.12 mg/m L和0.8 mg/m L;该粗提液能引起番茄早疫病菌菌丝的脂质过氧化程度和细胞内过氧化氢含量上升,菌丝细胞膜的蛋白质合成量下降,当粗提液浓度高于50 mg/m L时,菌丝细胞膜的麦角甾醇合成量下降;该粗提液还能降低番茄早疫病菌胞外果胶酶和纤维素酶的活性。研究表明,菌株011粗提液可作为生防制剂应用于植物病原真菌的防治。     

拮抗真菌HTC的鉴定及其对辣椒疫病的生物防治潜力

为明确拮抗真菌HTC对辣椒疫霉Phytophthora capsici的拮抗机制,采用平板对峙、形态学鉴定和18S rDNA序列比对分析等方法对菌株HTC进行了鉴定,并研究其发酵液与抗生物质粗提液对辣椒疫霉不同发育阶段的影响。经鉴定,菌株HTC为金色毛壳菌Chaetomium aureum。在平皿对峙试验中,菌株HTC的红色分泌物能抑制辣椒疫霉菌丝的生长,抑制率为59.1%,后期HTC菌丝可缠绕并降解辣椒疫霉菌丝。发酵液与抗生物质粗提液对辣椒疫霉不同发育阶段均有抑制作用,发酵液对辣椒疫霉菌丝生长的抑制率高达97.58%,对辣椒疫病的防治效果均高于70%。浇灌发酵液后,可提高辣椒苗的苯丙氨酸解氨酶、过氧化物酶、多酚氧化酶的活性,并明显促进辣椒苗生长,鲜重和干重增加32.27%和18.09%。研究表明,金色毛壳菌菌株HTC是一株具有开发潜力的生防菌株。     

Control of Citrus Green and Blue Molds with Garlic Extracts

Water and ethanol extracts of garlic cloves were applied to artificially inoculated citrus fruits to test their efficacy in the control of Penicillium digitatum and P. italicum, the cause of citrus green and blue mold respectively. Extracts were tested either alone, or in combination with vegetable (sunflower) cooking oil or fruit wax at the rate of (0.1% v/v), using two orange cultivars (Valencia and Shamouti), and grapefruit. Treated fruits were stored at 10±1 °C, and 90–95% relative humidity for 30 days. All concentrations of extracts were more effective than the water control in inhibiting the growth and development of both pathogens, but were not as effective as the fungicide treatment (imazalil 500 ppm + quazatine 1000 ppm). A remarkable increase in the activity of garlic extracts was observed when extracts were mixed with oil. Consequently, the treatment comprising 1% extract plus oil was as effective (100% control) as the fungicide treatment in controlling both green and blue molds on Valencia oranges.     

Induction of Resistance to Penicillium digitatum in Grapefruit by β-Aminobutyric Acid

-Aminobutyric acid (BABA), an inducer of pathogen resistance in plants, induced disease resistance in reproductive parts of the plant, such as grapefruit peel tissue. Application of BABA to specific wound sites on the fruit peel surface induced resistance to Penicillium digitatum, the main postharvest pathogen of citrus fruit, in a concentration-dependent manner, being most effective at 20mM, and rather less effective at either higher or lower concentrations. The effect of BABA in inducing resistance to P. digitatum in the fruit peel surface was local and limited to the vicinity (within 1–2cm) of the BABA-treated site. In addition to inducing pathogen resistance, increasing concentrations of BABA (from 1 to 100mM) also exhibited direct antifungal activity and inhibited P. digitatum spore germination and germ tube elongation in vitro. The induction of resistance to P. digitatum by BABA was accompanied by the activation of various pathogen defense responses in grapefruit peel tissue, including activation of chitinase gene expression and protein accumulation after 48h, and an increase in phenylalanine ammonia lyase (PAL) activity after 72h.     

柑桔贮藏病害发生动态和化学防腐保鲜技术的研究

作者1983～1995年间研究了浙江自然状态下柑桔贮藏病害的发生动态。结果显示,以采后侵染为主的病害发病率占59.79±22.40％;采前采后均可侵染,但以采前侵染为主的病害发病率占40.21±22.40％。后一类病害为害加剧是浙江柑桔贮藏病害发生的新动态,从国内外16种药剂中筛选出抑霉唑(Imazalil)、扑霉灵(Prochloraz)、百可得(Bellkute)等新型柑桔防腐保鲜剂,大量用于生产,解决了柑桔青、绿霉病菌对苯并咪唑类药剂的抗药性问题,经济和社会效益显著。研究了抑霉唑对柑桔青、绿霉病菌的敏感基线,在国内外首次报道大幅度降低使用浓度(仅原来的1/2～1/4)仍有良好效果,并率先在浙江桔区大量使用。     

Antifungal activity of sodium propylparaben alone or in combination with low doses of imazalil against Penicillium decay on citrus fruit

The performance of postharvest treatments with sodium propylparaben (SPP), alone or combined with low doses of the fungicide imazalil (IMZ), against citrus green (GM) and blue (BM) molds was evaluated on several citrus species and cultivars artificially inoculated with Penicillium digitatum and P. italicum, respectively, and incubated at 20 °C or cold-stored at 5 °C. Effectiveness of 100 mM SPP dips at 20 °C for 60 s was higher on oranges than on mandarins, with GM and BM incidence reductions of up to 60–90 % after 7 days at 20 °C. Irrespective of citrus cultivar and storage condition, SPP generally improved the curative action of 25 μl l^?1 IMZ to control Penicillium molds. In additional tests, 100 mM SPP dips at 20 °C for 60 s only prevented GM on ‘Valencia’ oranges inoculated 24 h after treatment when combined with IMZ. It can be concluded that postharvest SPP treatments show promise as an effective alternative to be considered in citrus postharvest disease control programs.     

Fenpropimorph: a promising fungicide for postharvest diseases in citrus fruits

Sour rot, green mold and blue mold are postharvest diseases of citrus fruit. Benzimidazole and imidazole fungicides control molds, and guazatine controls sour rot, but strains ofPenicillium spp. resistant to these chemicals have been reported. Aqueous formulations of fenpropimorph, a morpholine fungicide, are very active in controlling fungi attacking postharvest citrus fruits. The fungicidal effect of the chemical in the coating wax was investigated in combined treatments with guazatine in dip or spray applications on various citrus fruit varieties. Fenpropimorph alone was as good as or a better curative and protective treatment than the current commercial treatments applied in packinghouses in Israel for decay control.     

Improving Control of Green and Blue Molds of Oranges by Combining Pantoea Agglomerans (CPA-2) and Sodium Bicarbonate

The potential of using Pantoea agglomerans (strain CPA-2) alone, or in combination with sodium bicarbonate or sodium carbonate solutions, for control of Penicillium digitatum (green mold) and Penicillium italicum (blue mold) on oranges was investigated under ambient (20 °C) and cold storage (3 °C) conditions. P. agglomerans controlled both pathogens on oranges at 2 × 10⁸ cfu ml^-1. The biocontrol agent was found to be completely tolerant to 2% sodium bicarbonate at room temperature, although its culturability was reduced by > 1000-fold after 30 min in 2% sodium carbonate. The efficacy of P. agglomerans for control of green mold was improved when combined with sodium bicarbonate, resulting in complete and 97.6% reduction of decay incidence at 3 °C and 20 °C, when compared to untreated controls. Satisfactory results were also obtained with the combined treatment for control of blue mold. P. agglomerans grew well inside wounds on oranges at both 20 °C and 3 °C. In contrast, it showed a reduced growth on the surface of intact fruit. Sodium bicarbonate at 2% concentration did not noticeably affect antagonist population development. Thus, use of bicarbonate treatment at 2% followed by the antagonist P. agglomerans CPA-2 could be an alternative to chemicals for control of postharvest diseases on oranges.