钙对水杨酸诱导番茄叶片灰霉病抗性及防御酶活性的影响

以番茄‘L402’品种幼苗为试材,经水杨酸(SA)诱导处理后接种灰霉病菌,再进行外源Ca2+、Ca2+螯合剂和Ca2+抑制剂处理,分析Ca2+和SA处理番茄叶片对灰霉病抗性和主要防御酶系活性的变化,探讨Ca2+和SA对番茄诱导抗病性的影响。结果显示:(1)外源SA可显著提高番茄诱导叶和非诱导叶抗灰霉病能力,Ca2+能进一步增强SA诱导的抗病能力;而Ca2+螯合剂EGTA和质膜钙通道抑制剂LaCl3则不同程度地抑制了SA诱导的番茄灰霉病抗性。(2)外源SA能提高番茄诱导叶和非诱导叶中苯丙氨酸解氨酶(PAL)、多酚氧化酶(PPO)、过氧化物酶(POD)活性,外源Ca2+亦进一步增强了SA诱导的上述防御酶活性,但缺钙处理则不同程度降低这些防御酶活性。(3)外源补充Ca2+及不同缺钙处理对SA诱导的过氧化氢酶(CAT)和超氧化物歧化酶(SOD)活性未发现规律性影响。研究表明,钙对SA诱导番茄抗灰霉病性的增强效应,可能与其提高SA诱导番茄叶片中PAL、PPO和POD等防御酶活性有关。     

番茄灰霉病拮抗菌株初步鉴定及通过导入几丁质酶基因提高其生防效果

实验室保存菌Fh对番茄灰霉病有明显的抑制作用,通过形态特征、生理生化特征进行初步鉴定归属于芽孢杆菌属（Bacillus circulans）。从质粒pUC1965中得到含有几丁质酶基因的6.5kb DNA片段,将该基因片段与大肠杆菌 枯草芽孢杆菌穿梭质粒pBE2连接,获得重组质粒pBE2-chib。将重组质粒转入芽孢杆菌Fh中获得工程菌株Fh-chib。几丁质酶基因的PCR检测和几丁质平板实验表明几丁质酶基因被成功转入,工程菌株Fh-chib的原始粗酶液几丁质酶活为4.06U/ml。与野生菌相比,Fh-chib工程菌株对番茄灰霉病（Botrytis cinerea）抑菌效果提高34.46%。     

枯草芽孢杆菌磁场诱变株对采后番茄灰霉病的控制效果研究

对枯草芽孢杆菌(Bacillus subtilis)进行了磁场诱变,获得了39个诱变株,通过与番茄灰霉病菌(Botrytis cinerea Pers.)拮抗作用的研究,获得3株高效拮抗菌。实验结果表明,枯草芽孢杆菌BS0.25-1,BS1.25和BS0.10-1为高效拮抗菌株,其中BS1.25对采后番茄灰霉病防治效果较好,20℃下贮藏5天后,先接种BS1.25的处理防效达100%,显著好于对照,为较理想的拮抗菌。     

番茄枯萎病生防细菌的筛选及对植株防御酶活性的影响

为筛选防治番茄枯萎病的生防细菌,本研究利用梯度稀释涂板法和平板对峙生长法,从蚯蚓粪中筛选对番茄枯萎病有良好生防作用的细菌,对其中表现最好的菌株进行种属鉴定,并通过盆栽试验测定该菌株对番茄枯萎病的防治效果及对番茄体内防御酶活性的影响。结果表明,生防菌DX-25对番茄枯萎病菌的抑菌率达66.09%,初步鉴定为贝莱斯芽孢杆菌,盆栽防治效果达59.25%±0.43%。盆栽试验共设计CK、接种枯萎病菌(KW)、接种生防菌DX-25(DX),以及接种病原菌+生防菌DX-25(D+K) 4个处理,以超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、苯丙氨酸解氨酶(PAL)、多酚氧化酶(PPO)、脂氧合酶(LOX)、几丁质酶(CHT)和β-1,3-葡聚糖酶(GLU) 8种酶作为番茄抗病性反应指标,探究接种生防菌后对番茄植株防御酶活的影响。试验表明,各处理均能使番茄茎部的8种测定酶酶活显著高于对照; D+K处理在诱导PPO和GLU酶活方面表现出协同增效的作用,两者共同处理诱导的PPO、GLU达到显著水平的时间较单接种枯萎病菌和DX-25提前了48和24 h,说明DX-25与病原菌互作...     

生防细菌CNY-04筛选、鉴定及其对灰霉病菌的防效

【目的】为研究土壤细菌对蔬菜灰霉病的生防价值, 从辽宁、山东等地区的蔬菜种植基地采集土壤样本56份, 分离、筛选出对灰霉病具有稳定拮抗作用的细菌9株。【方法】采用平板对峙培养法进行初筛、复筛, 用抑菌圈法测定其抑菌效果, 并进行离体果实试验验证其对蔬菜灰霉病的防治效果, 通过形态学特征、生理生化特征及16S rRNA基因序列分析研究其分类地位。【结果】细菌CNY-04对蔬菜灰霉病的拮抗能力最强且遗传稳定, 抑菌圈直径达到34 mm; 初步鉴定该菌株为格氏沙雷菌(Serratia grimesii), 尚未见该菌在生防上的报道; CNY-04液体菌剂对离体番茄果实灰霉病的防效为69.23%, 50%多菌灵防效为75.39%, 24 h时接种CNY-04处理的番茄发病率为40.0%, 而48 h时接种处理的发病率为51.1%。【结论】CNY-04是一株较为理想的拮抗菌, 丰富了生防资源。     

一株产共轭亚油酸乳酸菌的鉴定及其特性

从酸菜汁中分离筛选到一株产共轭亚油酸(CLA)能力较高的乳酸菌。经鉴定,确定为植物乳杆菌Lactobacliius plantarum。微氧条件可提高CLA的产量,催化亚油酸(LA)生成CLA的酶受着LA的诱导。37℃对细胞生长和CLA生成最为有利。对数生长期为6～12h,18h后进入稳定期。在14～22h,CLA生成量快速增加,24h时达到最高值。该菌的培养物经萃取、甲酯化后,进行了气相色谱分离,生成的CLA产物为c9/t9,c11-CLA和t10,c12-CLA异构体的混合物。     

核黄素和接种番茄黄化曲叶病毒对番茄叶片防御酶活性的影响

以番茄品种‘1479’为材料,研究了喷施核黄素(Riboflavin)和接种番茄黄化曲叶病毒(TYLCV)对幼苗叶片中过氧化物酶(POD)、多酚氧化酶(PPO)、苯丙氨酸解氨酶(PAL)3种防御酶活性的影响。结果显示:(1)核黄素能显著降低番茄植株的番茄黄化曲叶病毒病的病情指数,并以2 mmol/L时诱导效果最佳,诱抗效果最高可达41.91%。(2)2mmol/L核黄素处理后96h内,番茄叶片的POD、PPO和PAL活性显著高于对照。(3)接种TYLCV后,核黄素处理和接种TYLCV处理均可诱导番茄叶片中防御酶活性显著增强。研究表明,核黄素处理可诱导POD、PPO和PAL活性的系统增强与番茄对TYLCV的诱导抗性密切相关。     

不同诱导处理对番茄叶片营养物质含量及防御酶活性的影响

本文研究了番茄在不同时间下受西花蓟马Frankliniella occidentalis危害(DTF)、机械损伤(MW)、茉莉酸(JA)和水杨酸甲酯(MeSA)外源诱导后,叶片营养物质含量和防御酶活性的变化。结果表明:各种诱导处理24 h和36 h时,番茄叶片可溶性蛋白和可溶性糖含量不同程度的下降,其中虫害处理36 h时,叶片可溶性蛋白和可溶性糖含量下降最明显;在48 h时除水杨酸甲酯处理外,番茄营养物质含量均显著升高。β-1,3葡聚糖酶(PR-2)活性在虫害、机械损伤和茉莉酸处理24 h和36 h后均升高,其中虫害处理的PR-2活性最高。各种处理均能诱导番茄叶片苯丙氨酸解氨酶(PAL)活性明显升高,且均随时间的延长持续升高。所有处理24 h时的番茄叶片多酚氧化酶(PPO)均被激发。各种处理均能导致植株的脂氧合酶(LOX)活性升高,但不同处理诱导的LOX活性升高的时间不同。结果表明,番茄能通过改变营养物质含量和防御酶活性对不同诱导处理作出生理应激反应,但反应程度与诱导方式和时间有关。     

一株番茄青枯病菌拮抗细菌的筛选、发酵条件优化及田间小区防效

[背景]番茄青枯病是由青枯劳尔氏菌(Ralstonia solanacearum)引起的一种土传细菌性病害,该病原菌严重影响番茄的生产。[目的]筛选番茄青枯病的生防细菌,并将其用于病害防治。[方法]采用抑菌圈法、琼脂扩散法从湖南衡阳青枯病发病田的健康番茄根际土壤筛选对青枯劳尔氏菌具有较强拮抗能力的菌株,通过形态学观察、生理生化试验、16S rRNA基因和gyrA基因测序分析确定其分类地位;以单因素试验和正交试验对发酵条件进行优化;通过田间小区试验初探其防效。[结果]筛选的菌株TR-1被初步鉴定为贝莱斯芽孢杆菌(Bacillus velezensislezensis);菌株TR-1最佳培养基配方(g/L):可溶性淀粉20.0,大豆蛋白胨10.0,磷酸氢二钾5.0;最佳发酵条件:pH6.0-7.0,温度30-33℃,摇床转速160 r/min,发酵时长48 h,优化后TR-1无菌发酵上清液对青枯菌抑菌圈直径达2.95 cm,约为优化前的2倍;其田间小区防效为60.30%。[结论]通过对菌株TR-1发酵条件进行优化可大大提升其发酵液抑菌效果,而且菌株TR-1在田间小区试验中对番茄青枯病防效优...     

番茄内生菌St24的鉴定及其对灰霉病的生防作用

从番茄植株根茎部分离到1株有抑菌活性的植物内生放线菌菌株St24,对其分类地位以及对灰霉病菌的防治效果进行研究.结果表明: 菌株St24为酒红链霉菌.St24发酵液经石油醚萃取得到的粗提物对多种病原菌有抑制作用,其中对灰霉病菌的抑制作用最强,抑制菌丝生长的EC₅₀为11.78 mg·L^-1.粗提物处理灰霉菌后,菌丝量减少,菌丝体皱缩、断裂、原生质外渗,菌体细胞表面有许多瘤状畸形.处理后的灰霉病菌培养液在260 nm处比对照多出现一吸收峰,说明粗提物对病原菌的细胞膜透性有影响.经盆栽试验, St24发酵液对番茄灰霉病有保护和治疗的作用,100 mg·L^-1粗提物叶面喷雾的保护作用效果最好,24 h后防效达到94.3%,120 h后为85.4%.     

抗灰葡萄孢霉菌乳酸菌的筛选

从80株乳酸菌中筛选出45株具有抗灰葡萄孢霉菌活性的乳酸菌菌株,其中10株具有较强抗灰葡萄孢霉菌活性。对这10株乳酸菌菌株的抗植物致病真菌谱进行了研究,这10株乳酸菌对番茄早疫病菌,甜瓜疫霉菌,甜瓜枯萎病菌,苹果炭疽病菌的生长均有较强的抑制作用。其中1株具有广谱抗植物致病真菌活性的乳酸菌菌株BX6-4为植物乳杆菌。经番茄离体叶片接种试验发现,植物乳杆菌BX6-4的发酵液能够在体外强烈地抑制灰葡萄孢霉菌的生长。     

The effects of lactic acid bacteria inoculants and formic acid on the formation of biogenic amines in grass silages

Silages were prepared in six laboratory experiments from four direct-cut grassland swards and pure swards of perennial ryegrass and false oat with dry matter contents ranging between 180 and 325?g/kg. Grass was fermented at 22°C and silages were stored at the same temperature for 4 months. Untreated silages (negative control) and silages preserved with 3?g/kg of formic acid (positive control) were compared with silages inoculated with commercial strains of Lactobacillus plantarum, Lactobacillus buchneri and a mixed preparation Microsil. The inoculants were applied at a dose of 5.10⁶ CFU/g of grass. Seven biogenic amines were extracted from silages with perchloric acid and determined as N-benzamides by micellar electrokinetic capillary chromatography. Common chemical quality parameters of silages were also determined. Tyramine, cadaverine and putrescine were the amines occurring at the highest concentration. As compared to untreated silages, formic acid was most effective to suppress formation of the main amines. Also the inoculants often decreased amine contents significantly (P?相似文献   

Inhibitory effects on microbial growth of Botrytis cinerea and Erwinia carotovora on potato using of a biopolymer chitosan at different molecular weights

The antimicrobial efficiency of chitosan at different molecular weights (5, 37, 57 and 290 kDa) against Botrytis cinerea and Erwinia carotovora on potato (Solanum tuberosum L.) was investigated. In vitro study showed that chitosan of 37 kDa was the most active against E. carotovora (minimum inhibitory concentration (MIC) = 950 mg/L), whereas 5 kDa chitosan was the most active against B.cinerea. Coating of potato tubers with 100, 250 and 500 mg/L significantly decreased the rate of weight loss and chitosan of 37 kDa showed the best effect. The in vivo antibacterial effect indicated that all treatments (500, 1000 and 2000 mg/L) significantly inhibited the growth of E. carotovora compared with the control. The lowest decay incidence was observed with 37 kDa chitosan. However, the antifungal activity against B. cinerea inoculated of leaves showed no decay incidence at 500 and 1000 mg/L with 57 kDa chitosan after 48 h.     

Antagonistic effects of volatiles generated by <Emphasis Type="Italic">Bacillus subtilis</Emphasis> on spore germination and hyphal growth of the plant pathogen, <Emphasis Type="Italic">Botrytis cinerea</Emphasis>

Botrytis cinerea is one of the most serious post-harvest pathogens of fruits and vegetables. Volatiles generated by Bacillus subtilis JA significantly inhibited both spore germination and elongation of germ tubes in Botrytis cinerea using a two-compartment agar-plate assay. The volatiles caused protoplasm retraction from the hyphal tips to the spores. Hua Chen and Xiang Xiao have contributed equally to this work.     

Study of the effects of temperature, pH, NaCl, and aw on the proteolytic and lipolytic activities of cheese-related lactic acid bacteria by quadratic response surface methodology

The individual and interactive effects of temperature, pH, NaCl, and a_w on the proteolytic and lipolytic activities of Lactobacillus delbrueckii subsp. bulgaricus B397, Lactococcus lactis subsp. lactis T12, and Lb. plantarum 2739 were studied by quadratic response surface methodology. The effects on enzyme activities depended on the interactions among the independent variables, type of activity, substrate and, especially, species. The proteinase activity of strains B397 and T12 was affected differently by pH as individual or interactive terms depending on the type of substrate _sl- or β-casein. The increase of NaCl concentration (2.5–7.5%) under cheese-like conditions had a negative effect on the proteinase activity of strain T12. The effect of NaCl was related to the corresponding decrease in a_w. Aminopeptidases N and A, iminopeptidase and endopeptidase of Lc. lactis subsp. lactis T12 were strongly inhibited by pH 5–6 and NaCl concentration higher than 3.75%. The negative effects of these independent variables was in several cases enhanced by their interaction and/or by the interaction with the lowest temperatures. In contrast, the same peptidases of Lb. plantarum 2739 retained a high activity under the very hostile environmental conditions. Iminopeptidase and especially endopeptidase activities of strain 2739 were stimulated slightly by NaCl at concentrations up to 5%. Lipase/esterase activity of Lb. delbrueckii subsp. bulgaricus B397 was markedly inhibited under cheese-like conditions.