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1.
A number of chemical and biological agents are known as inducers of systemic acquired resistance (SAR) to tobacco mosaic virus (TMV) in tobacco plants. In the present study, a local spray application of the non-protein amino acid DL-β-aminobutyric acid (BABA) was effective in enhancing resistance to TMV in tobacco plants containing the N gene. In contrast, the isomer α-aminobutyric acid (AABA) showed a much lower activity whereas γ-aminobutyric acid (GABA) was completely inactive, indicating a strong isomer specificity of aminobutyric acid in triggering enhanced virus resistance.Rapid cell death was detected in tobacco leaf tissues after foliar application of BABA, subsequently resulting in the development of macroscopically visible, necrotic lesions. BABA-induced cell death was associated with the rapid generation of superoxide and hydrogen peroxide. As further consequences, the occurrence of lipid peroxidation in treated tissues, a local and systemic increase of salicylic acid (SA) levels and the expression of PR-1a, a molecular marker of SAR in tobacco, could be observed. None of these responses was detectable after treatment with GABA.Enhancement of virus resistance by BABA was found to be strictly dependent on SA-mediated signal transduction since it could not be detected in salicylate hydroxylase (nahG) expressing transgenic tobacco plants. These findings suggest that in tobacco, primary processes triggered by foliar application of BABA, resemble those initiated by microbes during a hypersensitive response (HR) that result in SAR activation.  相似文献   

2.
Two foliar sprays of BABA (DL-3-amino-n-butanoic acid, DL-β-aminobutyric acid), or a mixture of BABA and different fungicides at reduced rates, effectively controlled (>90%) downy mildew, caused byPlasmopara viticola, in the foliage of field-grown grapevines. In five field trials BABA sprays resulted in a significant reduction of infectious leaf area and fungal sporulation, and of necrosis of oilspots. The level of disease control for BABA in four trials was similar to that achieved by metalaxyl-Cu or ‘Acrobat Plus’ (dimethomorph + mancozeb). Two-way tank-mixtures of BABA + fosetyl-AI, BABA + folpet, or BABA + Bion (benzothiadiazole), each at half the recommended rate, provided an additive effect againstP. viticola, performing as well as the full rate of each fungicide alone. BABA was not phytotoxic and did not affect pH, total titratable acids, or °Brix of the juice, as determined by commercial fungicidal standards. The results indicate that foliar applications of BABA can efficiently be integrated into a downy mildew control program in vineyards.  相似文献   

3.
Spray mixtures consisting of the plant activator BABA (DL-3-aminobutyric acid) and the protectant fungicide mancozeb were significantly more effective than BABA or mancozeb alone in controlling late blight (Phytophthora infestans) in potato and tomato and downy mildew (Pseudoperonospora cubensis) in cucumber. A mixture composed of 5 parts BABA and 1 part mancozeb (w/w, a.i.) exhibited a higher synergy factor than the 1+1 or the 1+5 (BABA + mancozeb) mixtures. No synergistic interaction was detected between BABA plus mancozeb in controlling sporangial or cystospore germination, nor mycelial growth ofP. infestans in vitro. The results showed enhanced effect of mancozeb in BABA-induced plants, suggesting, therefore, that lower dosages of this fungicide may be sufficient to control late blight or downy mildew under field conditions. http://www.phytoparasitica.org posting July 15, 2003.  相似文献   

4.
In this study, we investigated the ability of DL-3-aminobutyric acid (BABA) to protect tomato against bacterial wilt caused by Ralstonia solanacearum. This was combined with studies of accumulation of total phenolic compounds, free and total salicylic acid (SA), and activity of enzymes related to plant defence, i.e., polyphenol oxidase (PPO) and catalase (CAT). Under greenhouse conditions, tomato plants pre-treated by soil drenching with BABA profoundly reduced disease severity of bacterial wilt compared to plants receiving a soil drench with water. Thus, BABA reduced leaf wilting index by 75.3 % and vascular browning index by 69.9 %, without any in vitro inhibitory activity on the pathogen. BABA treatment significantly reduced the population of R. solanacearum in stems of tomato plants and additionally also significantly increased both fresh and dry weight of roots and shoots of tomato plants compared with the inoculated control. Application of BABA resulted in a high increase in PPO activity both in plants with and without inoculation. Compared to water-treated plants, treatment with BABA also induced a significant increase of total phenolic compounds as well as of free and total SA in leaves of both inoculated and non-inoculated tomato plants at all sampling times. CAT activity decreased in tomato plants treated with BABA in comparison with the water-treated control plants and the decrease in activity correlated with an increasing total SA accumulation. These findings suggest that BABA treatment resulted in induction of resistance to bacterial wilt in tomato.  相似文献   

5.
Downy mildew of lettuce (Bremia lactucae) is a serious disease. An alternative to chemicals is the application of disease resistance inducers. The aim of this study was to test whether DL--amino butyric acid (BABA) and Phytogard® (K2HPO3) could induce resistance in downy mildew susceptible plants. Aqueous solutions of BABA (0, 10, 20, 30, 50, 80, 100mM) and Phytogard® (0.0, 5.8, 29.0, 40.6, 58.0 and 87.0ppm) were sprayed on seven-day-old seedlings 0, 3, 7 and 15 days before or 1–3 days after inoculation with B. lactucae. Results obtained showed that Phytogard®- and BABA-induced resistance was dose-dependent. At 40.6ppm for Phytogard® and 10mM for BABA, complete protection was obtained. Both compounds had a curative effect and the induced resistance lasted for at least 15 days. It was also shown that both compounds induced systemic resistance in lettuce against downy mildew. Phytogard® at 40.6ppm completely inhibited spore germination while BABA at 20mM did not. Pathogenesis related (PR) protein analysis showed that BABA induced weak accumulation of PR-2, but not PR-1, PR-5 and PR-9. Phytogard® induced none of these proteins. The use of these two compounds to protect lettuce from B. lactucae is discussed.  相似文献   

6.
β-Aminobutyric Acid-induced Resistance in Plants   总被引：1，自引：0，他引：1  
Thehe broad sprectrum protective effect of the non-protein amino acid -aminobutyric acid (BABA) against numerous plant diseases has been well-documented in the literature. Here, we present an overview of BABA-induced protection in various pathosystems. Contriidictory reports concerning the mechanism of action underlying this type of protection incited us to take advantage of Arabidopsis/pathogen interactions as model systems to investigate the action of BABA at the genetic and molecular level. We present evidence that the protective effect of BABA is due to a potentiation of natural defense mechanisms against biotic and abiotic stresses. In order to dissect the pathways involved in potentiation by BABA describe the use of a mutational approach based on BABA-induced female sterility in Arabidopsis.  相似文献   

7.
BABA induced local and systemic resistance in lettuce (Lactuca sativa) against the Oomycete Bremia lactucae. Structure-activity analysis showed no induced resistance by related amino-butanoic acids or β-alanine. The R-enantiomer of BABA induced resistance whereas the S-enantiomer did not, suggesting binding to a specific receptor. Other compounds known to be involved in SAR signaling, including abscisic acid, methyl-jasmonate, ethylene, sodium-salicylate and Bion® (BTH) did not induce resistance. Systemic translocation of 14C-BABA and systemic protection against downy mildew were tightly correlated. BABA did not affect spore germination, appressorium formation, or penetration of B. lactucae into the host. Epifluorescence and confocal microscopy revealed that BABA induced rapid encasement with callose of the primary infection structures of the pathogen, thus preventing it from further developing intercellular hyphae and haustoria. Invaded host cells treated with BABA did not accumulate phenolics, callose or lignin, or express HR. In contrast, cells of genetically-resistant cultivars accumulated phenolics, callose and lignin and exhibited HR within one day after inoculation. The callose synthesis inhibitor DDG did not inhibit callose encasement nor compromised the resistance induced by BABA. PR-proteins accumulated too late to be responsible for the induced resistance. DAB staining indicated that BABA induced a rapid accumulation of H2O2 in the penetrated epidermal host cells. Whether H2O2 stops the pathogen directly or via another metabolic route is not known.  相似文献   

8.
DL-3-amino-butyric acid (BABA) induces local and systemic resistance against disease in numerous plant species. In a recent study we showed that preventive application of BABA to lettuce (Lactuca sativa) plants induced resistance against downy mildew caused by the oomycete Bremia lactucae by callose encasement of the primary infection structures of the pathogen. Now we show that post-infection application of BABA to the foliage or the roots, even at progressive stages of disease development, is highly protective against B. lactucae. Resistance induced by BABA is manifested in multiple microscopic forms, depending on the time of its application. When applied at 1 day post inoculation (dpi) BABA induced HR in penetrated epidermal cells; at 2 dpi it caused massive encasement with callose of the primary haustoria; and, at 3 or 4 dpi it enhanced the accumulation of H2O2 in the developing mycelia runners and altered their colour to red. The pronounced change in the colour of the mycelium was visually apparent to the naked eye. In all cases the pathogen failed to sporulate on the treated plants. This is the first indication that an immunizing compound may be protective at advanced stages of disease development.  相似文献   

9.
Interactions between Plasmopara helianthi, Glomus mosseae and two plant activators DL--amino-n-butyric acid (BABA) and CGA 245704 (acibenzolar-S-methyl (BTH)) in sunflower plants susceptible to downy mildew were studied in four experiments using different methods of treatment and pathogen inoculation. Both chemicals were applied as soil drenches and foliar sprays, whereas P. helianthi infection was obtained by root and cotyledon inoculations of the seedlings. Soil drenches at the rates of 50 and 100mgkg–1 soil of BABA and BTH given 1 and 3 days before P. helianthi inoculation, respectively to mycorrhizal plants, provided moderate protection against the pathogen (about 50–55%). Morphological changes and decrease in mycorrhizal colonization in roots of BTH-treated plants and in BTH-treated mycorrhizal plants were also observed. Delay in the emergence and reduction of the root systems were more evident at the highest concentration but decreased with time. These effects were absent with the BABA treatment.Foliar spray treatment of BABA and BTH, applied at 4000 and 200µgml–1, respectively (1 day post-inoculation) to mycorrhizal plants provided good protection (about 80%) against P. helianthi foliar infections. No effects on mycorrhizal colonization or on root systems were observed. In vitro tests on the effect of the compounds on the mycorrhizal fungus showed that the germination of G. mosseae sporocarps increased with BABA treatment whereas it was greatly inhibited by BTH treatment.  相似文献   

10.
Of the three isomers of aminobutyric acid, only the β isomer (BABA) was effective in inducing resistance against Peronospora parasitica , the causal agent of downy mildew, in cauliflower ( Brassica oleracea var. botrytis ). A single foliar spray applied to 7-day-old seedlings protected the plants against Peronospora parasitica for at least 15 days. Of the enantiomers (R and S), only the R was effective. Resistance was accompanied by a hypersensitive-like reaction (necrotic spots) which was evident before inoculation. BABA was systemically effective when applied to the roots, but failed to protect cotyledons adjacent to treated ones. Unlike other chemical inducers, BABA was effective when applied several hours postinoculation. It had no effect on P. parasitica spore germination. In cauliflower seedlings, BABA did not induce the accumulation of the pathogenesis-related protein PR-1, PR-2, PR-3, PR-5 and PR-9. Only treated and challenged seedlings accumulated PR-2.  相似文献   

11.
6-Azauracil caused a marked reduction in the number and size of local lesions on excisedNicotiana glutinosa leaves or leaf discs inoculated with tobacco mosaic virus or its nucleic acid. The amount of infectivity recovered from tobacco (N. tabacum White Burley) leaf discs floated on the pyrimidine analogue solution and subsequently ground and assayed 24, 48, 72, and 96 h after inoculation with intact virus was reduced in the 24, 48, and 72 h series but reached the same level as that of the water-treated control discs in the 96 h series.By contrast, the amount of infectivity in stripped epidermal tissue ofN. glutinosa leaves inoculated with nucleic acid was not reduced in strips floated on the analogue for 24, 50, and 70 h as compared with water-floated controls. The analogue had no effect on infectivity of the virus in vitro and did not act as an inhibitor of infection.Part of this paper was presented at the International Symposium on Plant Pathology, held in New Delhi from December 27, 1966 till January 1, 1967. A summary will be published in the symposium volume entitled Plant disease problems.  相似文献   

12.
Late blight caused by Phytophthora infestans is one of the most devastating diseases of the potato crop. Resistance breeding and current fungicides are unable to control the rapidly evolving P. infestans and new control strategies are urgently needed. This study examined mechanisms of dl ‐β‐aminobutyric acid (BABA)‐induced resistance (IR) in the potato–P. infestans system. Leaves from two cultivars that differ in their degree of resistance, Bintje and Ovatio, were analysed after foliar treatment with BABA. Rapid activation of various defence responses and a significant reduction in P. infestans growth were observed in leaves treated with BABA. In the more resistant cultivar, Ovatio, the activation was both faster and stronger than in Bintje. Microscopic analysis of leaves treated with BABA revealed induction of small hypersensitive response (HR)‐like lesions surrounded by callose, as well as production of hydrogen peroxide (H2O2). Molecular and chemical analyses revealed soluble phenols such as arbutin and chlorogenic acid and activation of PR‐1. These results show a direct activation of defence responses in potato, rather than priming as reported for other plant species. They also show that the efficiency of BABA‐IR differs between cultivars, which highlights the importance of taking all aspects into consideration when establishing new methods for disease management.  相似文献   

13.
Foliar sprays and soil drenches with DL--amino-n-butyric acid (BABA) reduced the number of Heterodera avenae and H. latipons cysts on wheat and barley. Foliar sprays of wheat with 8000mgl–1 BABA reduced the number of H. avenae cysts by 90%, whereas 2000mgl–1 BABA was enough to reduce the number of H. latipons cysts by 79%. Multiple spray treatments with 2000mgl–1 BABA at 10-day intervals reduced the number of H. avenae cysts on wheat and barley. A soil drench of wheat with 125mgl–1 BABA reduced the number of H. latipons cysts by 93% and H. avenae cysts by 43%. Second-stage juveniles of these nematodes penetrated and formed syncytia in wheat roots soil-drenched with BABA. More adult males of H. avenae were produced in BABA (<250mg1–1)-treated wheat roots (~76%) than in untreated roots (27%). Soil drenches with higher concentrations of BABA inhibited development of adult males and females. Several chemical elicitors of induced resistance were tested for their ability to reduce the number of H. avenae cysts on wheat. Only BABA was found to be an effective resistance inducer. The number of egg masses of an unidentified Meloidogyne sp. root-knot nematode, which infects only monocots, was also reduced by 95% by a soil drench of wheat with 500mgl–1 BABA. Development of this nematode inside the BABA-treated roots was also inhibited.  相似文献   

14.
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15.
 为了探究化学诱导剂诱导葡萄抗霜霉病的特性与葡萄内生菌激活的关系,筛选出对葡萄霜霉病有较高生防效果的菌株,本研究通过光学显微镜、扫描电子显微镜观察和传统培养法,检测了葡萄茎段的内生菌,并应用4种化学诱导剂对葡萄叶片和茎段进行处理,对被激活的内生菌进行分离和生防效果的测定。结果显示,在光学显微镜和扫描电子显微镜下均可观察到葡萄茎段内存在多种不同形态的内生细菌,但均处于不可培养状态;经不同浓度的诱导剂处理后叶片和茎段内生菌均增多,其中均以β-氨基丁酸(β-Aminobutyric acid, BABA)激活菌株数最多,诱导叶片和带叶茎段抗霜霉病效果最好,分别为80.4%和86.8%;被激活的叶片和茎段内生菌均为细菌,且多数为革兰氏阳性细菌,只有2株为革兰氏阴性细菌,其中,由BABA激活的革兰氏阴性细菌L-B-4生防效果高达97.2%,显著高于其他菌株,结合形态特征与16S rDNA序列分析,菌株L-B-4被鉴定为产氮假单胞杆菌(Pseudomonas azotoformans)。本文首次发现化学诱导剂在诱导葡萄抗霜霉病的过程中对葡萄内生细菌有激活作用,且被激活菌株对葡萄霜霉病有较高的生防效果。  相似文献   

16.
-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.  相似文献   

17.
Amzalek E  Cohen Y 《Phytopathology》2007,97(2):179-186
ABSTRACT Four inducers of systemic acquired resistance (SAR) were examined for their efficacy in controlling rust infection caused by Puccinia helianthi in sunflower plants. Of the four compounds, DL-3-amino-n-butanoic acid (DL-beta-aminobutyric acid [BABA]) was the most effective and sodium salicylate (NaSA) was the least effective in protecting against rust. In leaf disk assays, full protection was obtained with BABA at 25 mug/ml, benzodiathiazol-S-methyl ester (BTH) at 100 mug/ml, 2,6-di-chloroisonicotinic acid (INA) at 100 mug/ml, and NaSA at >200 mug/ml. L-2-amino-n-butanoic acid (AABA) was partially effective, whereas N-methyl-BABA and 4-aminobutnoic acid (GABA) were ineffective. The R-enantiomer of BABA, but not the S-enantiomer, was more effective than the racemic mixture. In intact plants, BABA applied as a foliar spray or a root dip, before or after (up to 48 h) inoculation, provided significant protection for 8 days. BTH, INA, and NaSA were less protective and more phytotoxic compared with BABA. BABA did not affect urediospore germination, germ tube growth, appressorial formation, or initial ingress of P. helianthi, but strongly suppressed mycelial colonization in the mesophyll and, consequently, pustule and urediospore formation. No accumulation of defense compounds (phenolics, lignin, or callose) was detected in BABA-treated inoculated or noninoculated plants. This is the first report on the activity of BABA against an obligate Basidomycete pathogen in planta.  相似文献   

18.
Induced resistance against Sclerotinia sclerotiorum in kiwifruit leaves   总被引：2，自引：0，他引：2  
Salicylic acid (SA), 1-aminocyclopropane-1-carboxylic acid (ACC) and DL -β-amino- n -butyric acid (BABA) were screened for the ability to induce phenylalanine ammonia lyase (PAL) activity in kiwifruit ( Actinidia deliciosa 'Hayward') leaves. SA (2 m M ) was the most effective and induced a 10-fold rise in PAL activity after 2 days compared with a four-fold rise 5 days after ACC (0.5 m M ) treatment. BABA was not an effective elicitor of PAL. SA was further tested, alongside a chlorinated analogue 4-chlorosalicylic acid (4CSA), for the ability to control Sclerotinia sclerotiorum on kiwifruit leaves. Pretreatment with SA and 4CSA caused a reduction in the size of lesions arising from subsequent S. sclerotiorum infection. 4CSA was the more effective and reduced disease levels, relative to controls, by up to 85% on leaf discs and 78% on leaves on the vine. This compares with a 48% reduction by SA on both. Resistance to infection was not affected by washing treated leaf discs prior to inoculation or by delaying inoculation for up to 4 days following 4CSA application. SA and 4CSA were rapidly absorbed and metabolized by kiwifruit leaves and had no apparent phytotoxic effects at the concentrations used for disease control studies. It is proposed that SA and 4CSA operate through the induction of host resistance mechanisms.  相似文献   

19.
Resistance to infection in plants can be induced by treatment with various chemicals. One such compound is β-aminobutyric acid (BABA). Its positive effect on disease resistance has been noted in several pathosystems. Here we demonstrate that treatment with BABA protects Brassica napus plants from infection by the fungal pathogen Leptosphaeria maculans. Surprisingly, BABA also displayes in vitro antifungal activity against L. maculans with EC50 similar to the fungicide tebuconazole. Both spore germination and hyphal growth were affected. The toxic effect can be reverted by addition of trypton to the culture medium. We hypothesised that BABA might inhibit inorganic nitrogen assimilation. Suppression of disease progression in plants and antifungal activity in vitro was weaker for α-aminobutyric acid and negligible for γ-aminobutyric acid. In contrast to a resistance inducer benzothiadiazole, the effect of BABA on disease development was nearly independent of the timing of treatment, indicating possible antifungal activity in planta. On the other hand, quantification of multiple hormones and an expression analysis have shown that treatment with BABA induces a synthesis of salicylic acid (SA) and expression of SA marker gene PR-1, but no evidence was observed for priming of SA responses to L. maculans. While we have not conclusively demonstrated how BABA suppresses the disease progression, our results do indicate that antifungal activity is another mechanism by which BABA can protect plants from infection.  相似文献   

20.
From 1996 to 1997, potassium silicate (SiO2) was tested at 0, 25, 50, and 100mgl–1 in hydroponics to control powdery mildew. Other elements were added in the usual amounts, and the strawberries were cultivated hydroponically in a greenhouse for 4 months (from October to January). The powdery mildew spread in the control plot, but little mildew developed in the plot with 25mgl–1 silicate, and none in plots with more than 50mgl–1 silicate. The suppressive effect lasted for about 4 months on fruits and even longer on leaves. On analysis of mineral content in the leaves, only the silicate content differed markedly between the control and treated plants. Nitrogen, phosphate, potassium, and calcium contents did not differ greatly. The maximum silicate content was about 24 times that of the control, and disease severity decreased significantly when the content was more than 1.5% in the leaves. The hardness of the strawberry leaves, measured by a creep meter, was increased by the silicate treatment.  相似文献   

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