287Phytopathol. Mediterr. (2010) 49, 287−300Corresponding author: L. K dịch - 287Phytopathol. Mediterr. (2010) 49, 287−300Corresponding author: L. K Trung làm thế nào để nói

287Phytopathol. Mediterr. (2010) 49

287
Phytopathol. Mediterr. (2010) 49, 287−300
Corresponding author: L. Kredics
Fax: +36 62 544823
E-mail: kredics@bio.u-szeged.hu
Introduction
Rhizoctonia solani Kühn (teleomorph: Thanatephorus cucumeris [A.B. Frank) Donk.]) is a widespread soil-borne pathogen that causes economically important diseases in many crops (Adams, 1988). Rice sheath blight caused by R. solani is one of the most serious diseases of rice worldwide, causing considerable yield losses (Sudhakar et al., 1998). The widespread adoption of new, susceptible, high-yielding cultivars with large numbers of tillers, and the changes in cultural practices associated with these cultivars, favor the development of sheath blight and contribute greatly to the rapid increase in the incidence and severity of this disease in rice-producing areas throughout the world (Groth et al., 1991; Rush and Lee, 1992). Furthermore, environmental conditions such as low light, cloudy days, high temperature and high relative humidity also favor the disease (Ou, 1985). The pathogen overwinters as soil-borne sclerotia and mycelium in plant debris; these constitute the primary inoculum. Control of the pathogen is difficult because of its ecological behavior, its extremely
Key words: biocontrol, Oryza sativa, Rhizoctonia solani, Trichoderma harzianum, Trichoderma virens.
Summary. Sheath blight caused by Rhizoctonia solani is one of the most serious rice diseases worldwide. The disease is currently managed only by the excessive application of chemical fungicides which are toxic and not environmentally friendly. Therefore, greater emphasis should be given to biological control as being both safe and effective. Trichoderma species are ubiquitous fungi in the soil and have an antagonistic activity against several soil-borne plant pathogens including R. solani. The present study was undertaken to evaluate the potential of indigenous Trichoderma strains from Mazandaran province, Northern Iran (a Mediterranean region on the southern coast of the Caspian Sea) against R. solani AG1-IA in vitro, and against sheath blight disease in the glasshouse, in order to find biocontrol isolates for application in the field. More than 200 Trichoderma strains were isolated from the soil, plant debris and the phyllosphere in rice fields. Strains were first screened for their antagonism to R. solani by in vitro antagonism tests including dual culture, antibiosis, the effect of Trichoderma strains on the production and viability of R. solani sclerotia, and hyperparasitism on microscopic slides. According to the in vitro experiments, several strains belonging to T. harzianum, T. virens and T. atroviride showed excellent biocontrol. These potential antagonist strains were further evaluated for their effectiveness in controlling sheath blight under glasshouse conditions. Among the 55 selected strains, seven significantly controlled the disease. T. harzianum AS12-2 was the most effective strain in controlling rice sheath blight, better even than propiconazole, the most commonly used fungicide in Iran.
Shahram NAEIMI1, Sayyed Mahmood OKHO VVAT1, Mohammad JAVAN-NIKKHAH 1, Csaba VÁGVÖLGYI2,
Vahid KHO SRA VI3 and Lás zló KREDICS2
1 Department of Plant Protection, Faculty of Agriculture, University of Tehran, Karaj 3158711167, Iran
2 Department of Microbiology, Faculty of Science and Informatics, University of Szeged,
Közép fasor 52. H-6726 Szeged, Hungary
3 Deputy of Iranian Rice Research Institute in Mazandaran, P.O. Box 145, Amol, Iran
Biological control of Rhizoctonia solani AG1-1A,
the causal agent of rice sheath blight with Trichoderma strains
Phytopathologia Mediterranea
S. Naeimi et al.
288
broad host range and the high survival rate of sclerotia under various environmental conditions (Groth et al., 2006). So far, no rice variety completely resistant to this fungus has been found, although extensive evaluation of rice germplasm has been conducted (Oard et al., 2004). In the absence of a desired level of host resistance, the disease is currently managed by excessive application of chemical fungicides, which have drastic effects on the soil biota, pollute the atmosphere, and are environmentally harmful. Some potentially effective fungicides are highly phytotoxic to rice and, if the disease is not severe, these fungicides may reduce yield (Groth et al., 1990). It is difficult to achieve control through host resistance or fungicides, therefore, biological control may be effective in minimizing the incidence of sheath blight (Das and Hazarika, 2000).
The anamorphic fungal genus Trichoderma (Hypocreales, Ascomycota) contains cosmopolitan soil-inhabiting fungi that are a major component of the mycoflora in soils of various ecosystems (Harman et al., 2004). The genus Trichoderma is especially known for its antagonistic activity against several plant pathogens, including R. solani (Papavizas, 1985; Chet, 1987; Harman and Björkman, 1998; Harman, 2006), and some strains are already commercialized as biocontrol agents (BCAs). These are also potential agents in suppressing rice sheath blight, they are highly competitive on rice plant residue and thus exhaust the nutrient supply for the pathogen and greatly reduce its survival (Mew and Rosales, 1984, 1985; Mostafa Kamal and Shahjahan, 1995).
Sheath blight is the most serious disease of high yielding rice cultivars in Mazandaran, the largest rice-growing province in Iran, on the southern coast of the Caspian Sea, which has a Mediterranean climate. The objective of this study was to evaluate the potential of indigenous Trichoderma isolates recovered from paddy rice fields in controlling R. solani, the rice sheath blight pathogen, in vitro and in vivo.
Materials and methods
Fungal isolates
Rhizoctonia solani RBL1, isolated from naturally infected rice plants with typical symptoms of sheath blight in a paddy field of Mazandaran province, Iran, was used in all experiments. R. solani strain RBL1 was obtained from the culture collection of the Iranian Rice Research Institute. The fungus was purified with the hyphal tip method and maintained on potato dextrose agar (PDA, Merck, Germany). To prove pathogenicity, inoculations were done in a glasshouse on Oryza sativa cv. Neda by placing a 5-mm mycelial plug of R. solani between the junction of the basal leaf sheath and the stem above the water line at the maximum tillering stage. R. solani was re-isolated from characteristic lesions of sheath blight. To confirm the anastomosis group (AG) and subgroup, a nuclear rDNA region, containing the ITS1 and 2 as well as the 5.8S gene (accession No. HM211085) was subjected to a BLAST search (Altschul et al., 1997) to find out the most similar sequences in the NCBI GenBank.
For the isolation of Trichoderma strains, soil samples were collected from rice fields located all over Mazandaran province (Figure 1), on the southern coast of the Caspian Sea. Soil was taken with an auger from a depth of 15 cm. Samples were air dried for 3–5 days at room temperature. Trichoderma isolates were obtained by the dilution plate method (Dhingra and Sinclair, 1995) on McFadden & Sutton’s RB-S-F Trichoderma selective medium (Davet and Rouxel, 2000). Sieved soil samples (10 g) were shaken in 90 mL sterile water for 10 minutes. For the isolation of Trichoderma from the rice phyllosphere, the leaves and stems were cut into small pieces (1 cm2), transferred to 500 mL Erlenmeyer flask with 100 mL sterile distilled water and placed on a shaker for one hour. A dilution series up to 10-6 was made from the samples. Aliquots (1 mL) were spread on Petri plates containing a selective medium and were then incubated at 25°C in the dark. Trichoderma isolates were also purified directly from fungal masses on rice debris. Putative Trichoderma colonies (from soil and foliage samples) were purified on PDA plates by the single spore method and deposited in the Microbiological Collection of the University of Szeged (SzMC).
DNA extraction and PCR conditions
For DNA preparation, a mycelium plug of each strain was placed on a cellophane disk sterilized by autoclaving in water and placed on the surface
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Biocontrol of rice sheath blight with Trichoderma
of yeast extract agar (5 g yeast extract, 5 g dextrose and 20 g agar L-1) for 2–3 days at room temperature. The fresh mycelium was scraped off and ground with a mortar and pestle in liquid nitrogen. Total DNA was extracted using the GenElute Plant Genomic DNA Miniprep Kit (Sigma-Aldrich, St. Louis, USA) according to manufacturer’s instructions.
A nuclear rDNA region containing the internal transcribed spacer (ITS) regions 1 and 2 and the 5.8S rRNA gene was amplified using the primers ITS1 and ITS4 (White et al., 1990). PCR amplifications were performed as described previously (Hermosa et al., 2000). Amplicons were purified with the GenElute PCR Clean-up Kit (Sigma-Aldrich) and sequenced at Macrogen Inc., Seoul, Korea. ITS sequences representing different ITS genotypes were submitted to the NCBI GenBank database (Table 1).
Species identification
A combination of morphological and molecular analysis was used for the identification of Trichoderma isolates. For morphological identification, strains were grown on 2% malt extract agar and on PDA under ambient laboratory conditions of light and temperature (about 21°C). Microscopic observations and measurements were made from preparations mounted in lactic acid. Individual isolates were identified at species level using standard mycological key (Gams and Bissett, 1998), species descriptions (Bissett, 1992; Samuels et al., 1999; Kraus et al., 2004), and TrichOKEY 2.0, an online method (http://www.isth.info/tools/molkey/index.php) for the quick and reliable molecular identification of Hypocrea and Trichoderma at the genus, clade, and species levels based on ITS1 and 2 sequences (Druzhinina et al., 2005). TrichOKEY identifies most species unequivocally, although some species have identical or very simi
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287
Phytopathol。医源性。(2010 年) 49,287−300
相应作者: L.克赖迪奇
传真: 36 62 544823
电子邮件: kredics@bio.u-szeged.hu
介绍
水稻纹枯病菌 Kühn (teleomorph: 纹螨 [A.B.弗兰克) 越长。])是广泛的土传病原导致经济上重要的疾病中许多作物 (Adams,1988年)。水稻纹枯病引起的。番茄早疫病菌是水稻世界范围内,造成相当大的产量损失 (Sudhakar 等人,1998年) 的最严重疾病之一。普遍采用的易感、 高产的新品种与大量的分蘖和这些品种,与相关的文化习俗的变化有利于发展的纹枯病和大大有助于迅速增加的发生率和严重程度的这种疾病在水稻生产领域在全世界 (格罗特等人,1991 年 ;拉什和李,1992年)。此外,低光、 阴天、 高的温度和湿度较高的环境条件也青睐这种疾病 (Ou,1985年)。以土源性菌核和菌丝体在植物碎片 ; 病菌越冬这些构成主要接种。控制的病原是困难的由于其生态的行为,其极
关键词: 生物防治,水稻,水稻纹枯病菌,哈茨木霉、 木霉病菌。
摘要。纹枯病水稻纹枯病菌是全世界最严重的水稻病害之一。这种疾病是目前仅有管理过度应用化学杀菌剂的毒性和环境不友好。因此,应该更重视生物控制作为既安全又有效。木霉菌物种是无处不在的真菌在土壤中,对几种植物土传病原包括枯拮抗。本研究进行了评价从伊朗北部 (地中海南部海岸的里海地区) 反对枯 AG1 IA 在体外,马赞达兰省土著木霉菌株的潜力并对纹枯病在温室中,为了找到生防菌株的领域中的应用。超过 200 多木霉菌株从土壤、 植物碎屑和叶围在稻田中。第一次菌株为枯对其拮抗作用的体外拮抗作用测试包括双重文化,抗菌,木霉菌株的生产和生存能力的枯菌核和在微观的幻灯片上寄生的影响。在体外实验中,属于木霉,几株 T.病菌和 T.atroviride 表明优秀的生物防治。这些潜在的拮抗剂菌株进行进一步评价其有效性在温室条件下控制纹枯病。55 选株,其中七个大大控制了病情。木霉 AS12-2 是最有效的应变控制水稻纹枯病,甚至比丙环唑,最常用的杀菌剂在伊朗。
沙赫拉姆 NAEIMI1赛义德马哈茂德玉壶 VVAT1、 穆罕默德 · 爪哇 NIKKHAH 1、 鲍 VÁGVÖLGYI2
Vahid KHO SRA VI3 和 Lás zló KREDICS2
1 部植物保护,农学部,德黑兰大学、 卡拉杰 3158711167,伊朗
2 部微生物学,科学学院和信息学、 塞格德大学
Közép fasor 52。匈牙利塞格德 H 6726
3 副伊朗马赞达兰,在水稻研究所邮政信箱 145、 阿莫,伊朗
的水稻纹枯病菌 AG1-1A、 生物控制
水稻纹枯病木霉菌株的因果代理
Phytopathologia 地中海
S.Naeimi et al.
288
宿主范围广泛和成活率较高的菌核在各种环境下 (格罗特等人,2006 年)。到目前为止,已发现没有完全抵抗这种真菌的水稻品种,虽然水稻种质资源的广泛的评价已进行 (Oard 等人,2004 年)。如果没有所需的寄主抗性级别,这种疾病是目前由管理过度应用化学杀菌剂,这种剧烈的影响,对土壤生物区系、 污染的空气,又对环境有害。一些潜在有效的杀菌剂是高度药害的水稻,并且,如果这种疾病不是严重的这类杀菌剂可能会减少产量 (格罗特等人,1990年)。它很难实现控制通过寄主抗性或杀菌剂,因此,生物控制可有效地减少 (Das 和扎,2000年) 的纹枯病的发生率.
变形真菌霉菌属的定义 (Hypocreales,子囊菌类) 包含大都会的土壤栖息在真菌的各种生态系统 (哈曼等人,2004 年) 的土壤中真菌的主要组成部分。属木霉尤其是闻名的拮抗作用对几种植物病原菌,包括枯 (Papavizas,1985 年 ;切特,1987 年 ;哈曼和 Björkman,1998 年 ;哈曼,2006 年),和一些株都已经商业化了作为生物防治剂 (宝鸡文理学院)。这些也是在抑制水稻纹枯病的潜在代理商,他们对水稻植物残极具竞争性和因而排气病原体的养分供应,大大降低其生存 (水电部和罗萨莱斯,1984 年,1985 年 ;穆斯塔法 · 卡迈勒和沙迦罕,1995年).
纹枯病是高高产水稻品种在马赞达兰,最大的水稻种植省在伊朗南部海岸的里海,有地中海气候的最严重的疾病。这项研究的目的是评估的土著木霉菌株从稻田中控制枯,水稻纹枯病病菌,恢复潜力在体外和
材料和方法
真菌分离株
水稻纹枯病菌 RBL1,分离的自然感染的水稻纹枯病在伊朗马赞达兰省的水田中的典型症状在所有实验中使用。 体内。枯株 RBL1 被从伊朗的水稻研究所文化集合。这种真菌菌丝顶端法纯化,保持对马铃薯葡萄糖琼脂 (PDA,默克公司、 德国)。为了证明致病性,免役都是枯的叶鞘的在温室里对水稻稻品种妮达的在最大分蘖期交界的基部和水线以上干之间放置一个 5 毫米菌丝插头。。番茄早疫病菌是重新孤立在纹枯病的特征性病变。要确认吻合术组 (AG) 和分组,一个核 rDNA 区域,包含它们的 ITS1 和 2,以及 5.8S 基因 (加入号HM211085) 曾遭受 BLAST 搜索 (特舒尔等人,1997年) 来找出最相似的序列在
木霉菌株的分离 NCBI 基因。稻田遍布马赞达兰省 (图 1),从里海的南部海岸上采集土壤样品。土壤被了从深度 15 厘米.样品的俄歇了空气干燥室温 3 — — 5 天。用稀释平板法 (Dhingra 和辛克莱,得到木霉分离物1995 年) 上麦克法登 & 萨顿的 RB-S-F 木霉菌选择性培养基 (Davet 和 Rouxel,2000年)。被筛的土壤样品 (10 g) 被动摇 90 毫升无菌水中 10 分钟。木霉分离水稻叶围的叶子和茎都切成小块 (1 cm2),转移到 500 毫升锥形瓶与 100 毫升无菌蒸馏水水,放在摇床上一个小时。起来一稀释系列到 10-6 由样品。整除数 (1 毫升) Petri 板有选择性培养基上迅速传播,然后孵育在 25 ° C 在黑暗中。木霉菌株也进行纯化直接从真菌群众对水稻碎片。(从土壤和树叶的样本) 的假定木霉殖民地被 PDA 平板方法纯化单孢和存放在塞格德大学 (SzMC) 微生物集合.
DNA 提取及 PCR 条件
DNA 制备方法,每一株菌丝体插头放在玻璃纸磁盘上灭菌的高压灭菌水中和放在表面,
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水稻纹枯病的生防木霉菌
酵母提取物琼脂 5 克葡萄糖和葡萄糖 20 g 琼脂 L 1 5 g 酵母抽提物) 在室温下 2 — — 3 天。新鲜菌丝被刮掉和地面与砂浆,杵在液氮中。使用 GenElute 植物基因组 DNA 微量工具包 (西格玛奥德里奇,圣 Louis 中提取总 DNA美国) 根据制造商的说明。
核 rDNA 区域包含内转录的间隔 (其) 区域 1 和 2 和 5.8S rRNA 基因扩增使用的引物,它们的 ITS1 和 ITS4 (白等,1990年)。如前面所述进行 PCR 扩增 (Hermosa 等人,2000 年)。扩增与 GenElute PCR 清洁工具包 (西格玛-奥德里奇) 纯化测序在 Macrogen Inc.,首尔,韩国。其代表不同的序列及其基因型提交 NCBI 基因数据库 (表 1).
物种鉴定
结合形态学和分子分析用于木霉菌株的鉴定。形态学鉴定,株种植在 2%麦芽浸膏琼脂上和在 pda 上的光照和温度 (约 21 ° C) 的环境在实验室条件下。显微镜的观察和测量是由安装在乳酸的筹备工作。在物种水平使用标准的真菌学关键 (Gams 和比塞特,1998年),确定了单个菌株物种描述 (比塞特,1992 年 ;塞缪尔斯 et al.,1999 年 ;克劳斯等人,2004 年),和 TrichOKEY 2.0,快速和可靠的分子鉴定的菌生种和木霉属、 分支和物种各级在它们的 ITS1 和 2 序列 (Druzhinina 等人,2005 年) 的基础的一种在线方法 (http://www.isth.info/tools/molkey/index.php)。TrichOKEY 标识大多数物种毫不含糊地,不过有些物种的完全相同或非常西米
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287
Phytopathol. Mediterr. (2010) 49, 287−300
Corresponding author: L. Kredics
Fax: +36 62 544823
E-mail: kredics@bio.u-szeged.hu
Introduction
Rhizoctonia solani Kühn (teleomorph: Thanatephorus cucumeris [A.B. Frank) Donk.]) is a widespread soil-borne pathogen that causes economically important diseases in many crops (Adams, 1988). Rice sheath blight caused by R. solani is one of the most serious diseases of rice worldwide, causing considerable yield losses (Sudhakar et al., 1998). The widespread adoption of new, susceptible, high-yielding cultivars with large numbers of tillers, and the changes in cultural practices associated with these cultivars, favor the development of sheath blight and contribute greatly to the rapid increase in the incidence and severity of this disease in rice-producing areas throughout the world (Groth et al., 1991; Rush and Lee, 1992). Furthermore, environmental conditions such as low light, cloudy days, high temperature and high relative humidity also favor the disease (Ou, 1985). The pathogen overwinters as soil-borne sclerotia and mycelium in plant debris; these constitute the primary inoculum. Control of the pathogen is difficult because of its ecological behavior, its extremely
Key words: biocontrol, Oryza sativa, Rhizoctonia solani, Trichoderma harzianum, Trichoderma virens.
Summary. Sheath blight caused by Rhizoctonia solani is one of the most serious rice diseases worldwide. The disease is currently managed only by the excessive application of chemical fungicides which are toxic and not environmentally friendly. Therefore, greater emphasis should be given to biological control as being both safe and effective. Trichoderma species are ubiquitous fungi in the soil and have an antagonistic activity against several soil-borne plant pathogens including R. solani. The present study was undertaken to evaluate the potential of indigenous Trichoderma strains from Mazandaran province, Northern Iran (a Mediterranean region on the southern coast of the Caspian Sea) against R. solani AG1-IA in vitro, and against sheath blight disease in the glasshouse, in order to find biocontrol isolates for application in the field. More than 200 Trichoderma strains were isolated from the soil, plant debris and the phyllosphere in rice fields. Strains were first screened for their antagonism to R. solani by in vitro antagonism tests including dual culture, antibiosis, the effect of Trichoderma strains on the production and viability of R. solani sclerotia, and hyperparasitism on microscopic slides. According to the in vitro experiments, several strains belonging to T. harzianum, T. virens and T. atroviride showed excellent biocontrol. These potential antagonist strains were further evaluated for their effectiveness in controlling sheath blight under glasshouse conditions. Among the 55 selected strains, seven significantly controlled the disease. T. harzianum AS12-2 was the most effective strain in controlling rice sheath blight, better even than propiconazole, the most commonly used fungicide in Iran.
Shahram NAEIMI1, Sayyed Mahmood OKHO VVAT1, Mohammad JAVAN-NIKKHAH 1, Csaba VÁGVÖLGYI2,
Vahid KHO SRA VI3 and Lás zló KREDICS2
1 Department of Plant Protection, Faculty of Agriculture, University of Tehran, Karaj 3158711167, Iran
2 Department of Microbiology, Faculty of Science and Informatics, University of Szeged,
Közép fasor 52. H-6726 Szeged, Hungary
3 Deputy of Iranian Rice Research Institute in Mazandaran, P.O. Box 145, Amol, Iran
Biological control of Rhizoctonia solani AG1-1A,
the causal agent of rice sheath blight with Trichoderma strains
Phytopathologia Mediterranea
S. Naeimi et al.
288
broad host range and the high survival rate of sclerotia under various environmental conditions (Groth et al., 2006). So far, no rice variety completely resistant to this fungus has been found, although extensive evaluation of rice germplasm has been conducted (Oard et al., 2004). In the absence of a desired level of host resistance, the disease is currently managed by excessive application of chemical fungicides, which have drastic effects on the soil biota, pollute the atmosphere, and are environmentally harmful. Some potentially effective fungicides are highly phytotoxic to rice and, if the disease is not severe, these fungicides may reduce yield (Groth et al., 1990). It is difficult to achieve control through host resistance or fungicides, therefore, biological control may be effective in minimizing the incidence of sheath blight (Das and Hazarika, 2000).
The anamorphic fungal genus Trichoderma (Hypocreales, Ascomycota) contains cosmopolitan soil-inhabiting fungi that are a major component of the mycoflora in soils of various ecosystems (Harman et al., 2004). The genus Trichoderma is especially known for its antagonistic activity against several plant pathogens, including R. solani (Papavizas, 1985; Chet, 1987; Harman and Björkman, 1998; Harman, 2006), and some strains are already commercialized as biocontrol agents (BCAs). These are also potential agents in suppressing rice sheath blight, they are highly competitive on rice plant residue and thus exhaust the nutrient supply for the pathogen and greatly reduce its survival (Mew and Rosales, 1984, 1985; Mostafa Kamal and Shahjahan, 1995).
Sheath blight is the most serious disease of high yielding rice cultivars in Mazandaran, the largest rice-growing province in Iran, on the southern coast of the Caspian Sea, which has a Mediterranean climate. The objective of this study was to evaluate the potential of indigenous Trichoderma isolates recovered from paddy rice fields in controlling R. solani, the rice sheath blight pathogen, in vitro and in vivo.
Materials and methods
Fungal isolates
Rhizoctonia solani RBL1, isolated from naturally infected rice plants with typical symptoms of sheath blight in a paddy field of Mazandaran province, Iran, was used in all experiments. R. solani strain RBL1 was obtained from the culture collection of the Iranian Rice Research Institute. The fungus was purified with the hyphal tip method and maintained on potato dextrose agar (PDA, Merck, Germany). To prove pathogenicity, inoculations were done in a glasshouse on Oryza sativa cv. Neda by placing a 5-mm mycelial plug of R. solani between the junction of the basal leaf sheath and the stem above the water line at the maximum tillering stage. R. solani was re-isolated from characteristic lesions of sheath blight. To confirm the anastomosis group (AG) and subgroup, a nuclear rDNA region, containing the ITS1 and 2 as well as the 5.8S gene (accession No. HM211085) was subjected to a BLAST search (Altschul et al., 1997) to find out the most similar sequences in the NCBI GenBank.
For the isolation of Trichoderma strains, soil samples were collected from rice fields located all over Mazandaran province (Figure 1), on the southern coast of the Caspian Sea. Soil was taken with an auger from a depth of 15 cm. Samples were air dried for 3–5 days at room temperature. Trichoderma isolates were obtained by the dilution plate method (Dhingra and Sinclair, 1995) on McFadden & Sutton’s RB-S-F Trichoderma selective medium (Davet and Rouxel, 2000). Sieved soil samples (10 g) were shaken in 90 mL sterile water for 10 minutes. For the isolation of Trichoderma from the rice phyllosphere, the leaves and stems were cut into small pieces (1 cm2), transferred to 500 mL Erlenmeyer flask with 100 mL sterile distilled water and placed on a shaker for one hour. A dilution series up to 10-6 was made from the samples. Aliquots (1 mL) were spread on Petri plates containing a selective medium and were then incubated at 25°C in the dark. Trichoderma isolates were also purified directly from fungal masses on rice debris. Putative Trichoderma colonies (from soil and foliage samples) were purified on PDA plates by the single spore method and deposited in the Microbiological Collection of the University of Szeged (SzMC).
DNA extraction and PCR conditions
For DNA preparation, a mycelium plug of each strain was placed on a cellophane disk sterilized by autoclaving in water and placed on the surface
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of yeast extract agar (5 g yeast extract, 5 g dextrose and 20 g agar L-1) for 2–3 days at room temperature. The fresh mycelium was scraped off and ground with a mortar and pestle in liquid nitrogen. Total DNA was extracted using the GenElute Plant Genomic DNA Miniprep Kit (Sigma-Aldrich, St. Louis, USA) according to manufacturer’s instructions.
A nuclear rDNA region containing the internal transcribed spacer (ITS) regions 1 and 2 and the 5.8S rRNA gene was amplified using the primers ITS1 and ITS4 (White et al., 1990). PCR amplifications were performed as described previously (Hermosa et al., 2000). Amplicons were purified with the GenElute PCR Clean-up Kit (Sigma-Aldrich) and sequenced at Macrogen Inc., Seoul, Korea. ITS sequences representing different ITS genotypes were submitted to the NCBI GenBank database (Table 1).
Species identification
A combination of morphological and molecular analysis was used for the identification of Trichoderma isolates. For morphological identification, strains were grown on 2% malt extract agar and on PDA under ambient laboratory conditions of light and temperature (about 21°C). Microscopic observations and measurements were made from preparations mounted in lactic acid. Individual isolates were identified at species level using standard mycological key (Gams and Bissett, 1998), species descriptions (Bissett, 1992; Samuels et al., 1999; Kraus et al., 2004), and TrichOKEY 2.0, an online method (http://www.isth.info/tools/molkey/index.php) for the quick and reliable molecular identification of Hypocrea and Trichoderma at the genus, clade, and species levels based on ITS1 and 2 sequences (Druzhinina et al., 2005). TrichOKEY identifies most species unequivocally, although some species have identical or very simi
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病原。mediterr。(2010)49,287−300
通讯作者:L. kredics
传真:36 62 544823
电子邮件:kredics”生物。u-szeged。胡
介绍
立枯丝核菌üHN(有性型水稻纹枯病菌[该弗兰克)驴。])是一种普遍存在的土壤传播的病原体,导致许多作物的经济意义疾病(亚当斯,1988)。水稻纹枯病R.纹枯病是水稻全世界最严重的疾病,造成相当大的产量损失(院等人。,1998)。新的,敏感的广泛采用,大量分蘖穗高产品种,这些品种和文化实践相关的变化,有利于纹枯病的发展大大有助于在水稻产区在世界范围内的发病率和严重程度迅速增加(格罗斯等人。,1991;高峰和Lee,1992)。此外,环境条件,如低灯,阴天,温度高、相对湿度也有利于疾病(欧,1985)。病原菌以菌核和菌丝体在土传植物碎片;这些构成的主要接种。病原体的控制是困难的因为它的生态行为,其极
关键词:生物防治,水稻,立枯丝核菌,木霉,木霉黄桷树
总结。纹枯病是世界最严重的水稻病害。这种疾病是目前唯一的化学农药是有毒的和不环保的过度应用管理。因此,更应重视生物控制是安全和有效的。木霉是一类在土壤中无处不在的真菌并对多种土传植物病原菌拮抗活性包括R.。本研究的目的是评估在马赞德兰省土著木霉菌株的潜力,伊朗北部地区(地中海地区在南部的里海沿岸)体外对水稻纹枯病菌AG1-IA,并对纹枯病的温室中,为了寻找生物分离领域中的应用。从土壤中分离的200余株木霉,植物碎片与水稻领域叶面。菌株筛选拮抗R.菌的体外拮抗试验包括双文化,抗菌,木霉菌株对水稻纹枯病菌菌核产量和活力的影响,并对微观幻灯片重寄生。根据在体外实验中,几株哈茨木霉,T.黄桷树和T.atroviride具有优良的生物防治。这些潜在的拮抗菌株进一步评估其有效性,控制纹枯病的温室条件下。55个选定的菌株之间,七的显着控制疾病。哈茨木霉as12-2是防治水稻纹枯病的最有效的应变,比丙环唑更好,在伊朗最常用的杀菌剂。
Shahram naeimi1,赛义德马哈茂德玉壶vvat1,穆罕默德javan-nikkhah 1,乔VÁGVÖlgyi2,
瓦希德Kho SRA VI3和Lá的ZLókredics2
1植物保护系,农学,德黑兰,卡拉杰3158711167大学微生物学系,伊朗2系
,情报学,赛格德大学,
KöZéP FASOR 52。h-6726塞格德,匈牙利
3副在马赞德兰伊朗水稻研究所,邮政信箱145,急性单核细胞白血病,立枯丝核菌ag1-1a伊朗
生物控制,
与木霉菌株
phytopathologia地中海
美国内伊米等人水稻纹枯病的病原。
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广泛的宿主范围和不同环境条件下菌核存活率高(格罗斯等人。,2006)。到目前为止水稻品种,没有完全抵抗这种真菌被发现,虽然水稻种质资源进行了广泛的评估(上等人。,2004)。在一个理想的宿主抗性水平缺乏,疾病是目前化学药剂过量应用管理,这对土壤生物的强烈影响,污染大气,而且对环境有害的。一些可能有效的杀菌剂,对水稻高度的植物毒性,如果病情不严重,这些杀菌剂可能会降低产量(格罗斯等人。,1990)。这是难以通过寄主抗性或杀菌剂,实现控制,因此,生物控制可以减小纹枯病发生有效(DAS和
表示,2000)。变形真菌木霉属(Hypocreales,子囊)包含了世界性的土栖真菌在不同生态系统土壤真菌区系的主要组成部分(哈曼等人。,2004)。木霉属是特别是其对几种植物病原菌的拮抗活性,包括水稻纹枯病菌(papavizas,1985;切特,1987;哈曼和BJ rkmanö,1998;哈曼,2006),和一些菌株已经商业化,作为生物控制剂(BCAS)。这些也都是潜在的药物在抑制水稻纹枯病,他们具有很强的竞争力,对水稻植株的残留,因此排气养分供应的病原体,大大降低其生存(新罗萨莱斯,1984,1985;卡马尔,穆斯塔法沙迦罕,1995)。
纹枯病是水稻高产品种的马赞达兰最严重的疾病,最大的水稻生长在伊朗省,在南部的里海沿岸,其中有一个地中海气候。本研究的目的是评估潜在的土著木霉菌株水稻纹枯病菌恢复控制领域中,水稻纹枯病菌,在体外和体内
。材料和方法
真菌菌株
立枯丝核菌RBL1,从自然感染水稻植株在马赞德兰省,稻田纹枯病的典型症状,伊朗分离,在所有的实验中使用。从伊朗水稻研究所收集的文化得到了水稻纹枯病菌菌株RBL1。真菌的菌丝尖端纯化方法和保持在马铃薯葡萄糖琼脂培养基(PDA,默克公司,德国)。证明的致病性,接种于水稻品种温室里做的。内放置一个5毫米的水稻纹枯病菌的菌丝插头的基生叶鞘和茎以上的水在最大分蘖期之间的交界处。R.病菌被重新从纹枯病的特征性病变是孤立的。确认吻合组(AG)和亚群,核rDNA区域,包括ITS1和2以及5.8S基因(登录号hm211085)进行BLAST(Altschul等人。,1997)中找出最相似的序列在NCBI GenBank
对木霉菌株。隔离,土壤样品从水稻领域遍布马赞德兰省采集(图1),在南部的里海沿岸。土壤被从一个15厘米深的螺旋。样品经风干3–5天在室温下。木霉菌株的稀释平板法得到(Dhingra和辛克莱,1995)麦克法登&萨顿的rb-s-f木霉菌选择性培养基(davet和该公司,2000)。过筛的土壤样品(10克)动摇了在90毫升无菌水10分钟。从水稻根际分离的木霉菌,叶和茎切成小块(1平方厘米),转移到500毫升三角瓶100毫升无菌蒸馏水,放在摇床一小时。系列稀释到10-6由样品。样品(1毫升)被扩展Petri板包含一个选择性培养基,然后在25°C培养在黑暗中。木霉菌株真菌也从群众对水稻碎片直接净化。假定的木霉菌菌落(从土壤和植物样品)进行纯化,PDA平板的单孢子的方法和存放在赛格德大学的微生物的集合(szmc)。
DNA提取和PCR
DNA制备条件下,各菌株菌丝体插放在一个玻璃盘通过高压灭菌水,放在表面
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酵母提取物琼脂2010
水稻纹枯病的防治(5克酵母提取物,5 g葡萄糖和20克琼脂L-1)2–3天在室温下。新鲜菌丝刮掉和地面在液氮的研钵和杵。使用genelute植物基因组DNA小量提取试剂盒提取的总DNA(∑-奥德里奇,圣路易斯,美国)根据制造商的指示。
含有内部转录间隔区(ITS)核rDNA区域1和2,5.8S rRNA基因的引物ITS1和ITS4扩增(白等人。,1990)。PCR扩增如以前所说的进行(Hermosa等人。,2000)。纯化的genelute PCR纯化试剂盒扩增产物(西格玛奥德里奇)和测序在macrogen Inc.,汉城,韩国。其序列代表不同的基因型被提交到NCBI GenBank数据库(表1)。
物种鉴定
结合形态学和分子分析用于木霉的分离株的鉴定。形态学鉴定,菌株2%麦芽提取物琼脂和PDA的光照和温度的实验环境条件下生长的(约21°C)。显微观察和测量了从安装在乳酸制剂。个别菌株被确定在种的水平使用标准的真菌学的关键(GAMS和拔萃,1998),物种的描述(拔萃,塞缪尔等人,1992;1999;克劳斯等人。,2004),和trichokey 2,一个在线的方法(http://www.isth.info/tools/molkey/index.php)的快速在属,分支的红和绿色木分子识别和可靠的,和物种水平基于ITS1和2序列(druzhinina等人。,2005)。大多数物种trichokey标识明确,尽管一些物种具有相同或非常相似的
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