Salicylic acid mediated multi-pronged strategy to combat bacterial blight disease (<Emphasis Type="Italic">Xanthomonas axonopodis</Emphasis> pv. <Emphasis Type="Italic">punicae</Emphasis>) in pomegranate

Pomegranate bacterial blight disease caused by Xanthomonas axonopodis pv. punicae is one of the most serious threat to the pomegranate industry in India. So far, the chemicals used to control this pathogen alone are less effective. In this article, an attempt was made to supplement chemical control through improving the systemic acquired resistance of plant using nutrients such as nitrogen (N) and salicylic acid (SA) as elicitor. The study revealed that foliar application of SA at the rate of 300 ppm increased above-ground dry mass of plant by 64.97%, improved chlorophyll content of leaves and resulted higher concentration of macro-elements and micro-elements, particularly Mn and Zn, in leaves. It also significantly increased the activities of nitrate reductase (NR), superoxide dismutase (SOD), catalase and peroxidase. However, the maximum response of SA was recorded when it was sprayed after soil application of N at 100% of the recommended dose. As a consequence, this combination recorded the least bacterial blight infection with average severity of 11.58% followed by without-N application under challenge inoculation of the pathogen. However, sustainable production cannot be realized without N application. The integration of this strategy for activation of defence mechanism of plant with the bactericide streptocycline resulted in further reduction of bacterial blight disease incidence and severity under field condition to very low levels (3.84% and 18.57% respectively).     

Effects of Plant Defence Activators on Anthracnose Disease of Cashew

The plant defence activators acibenzolar-S-methyl (Benzo[1,2,3]thiadiazole-7-carbothioic acid-S-methyl ester, ASM), 2,6-dichloro-isonicotinic acid (DCINA), salicylic acid (SA), and dibasic potassium phosphate (K₂HPO₄) were tested for their ability to protect cashew (Anacardium occidentale) seeds and leaves from anthracnose disease caused by Colletotrichum gloeosporioides. No inhibition of the early stages of pathogen development was caused by concentrations equal to or lower than 1.1mM a.i. ASM, 1.2mM a.i. DCINA, 5mM SA and 50mM K₂HPO₄. Maximum reduction of the disease in detached leaves, without phytotoxic effects, was obtained with 0.07mM a.i. ASM and DCINA, 5mM SA, and 50mM K₂HPO₄, with a time interval of at least 72h between application of the activator and inoculation with the pathogen. On attached leaves, foliar sprays were slightly more efficient than soil drench treatments, with 5mM SA being the most effective treatment, while 50mM SA as well as 0.3mM a.i. ASM and DCINA caused phytotoxic effects. In field-grown plants, protection was conferred by a soil drench of concentrations as low as 12.6M a.i. ASM and DCINA and 2.6mM SA. These concentrations were not phytotoxic suggesting that plant defence activators have potential for control of anthracnose disease in the field.     

Extract of Hedera helix induces resistance on apple rootstock M26 similar to Acibenzolar-S-methyl against Fire Blight (Erwinia amylovora)

The potential of acibenzolar-S-methyl (Benzo [1,2,3]thiadiazole-7-carbothioic acid-S-methyl ester, ASM; Bion 50 WG) and of an extract of Hedera helix, to protect M26 apple rootstocks against fire blight was determined under controlled conditions. Marked differences were observed in the rate and extent of multiplication as well as in pathogen cell viability between control and ASM and H. helix-treated rootstocks. Although the pathogen multiplied abundantly in the plant tissue of water-treated rootstocks and showed severe damage, ASM and the plant extract of H. helix applied prior to inoculation with the causal agent of fire blight, E. amylovora (strain 7/74), suppressed disease development and bacterial multiplication. Physiological observations of ASM and plant extract-treated rootstocks indicated that restriction of pathogen colonization in plant tissue was correlated with a pronounced increase of peroxidase (POX) and chitinase activity. Furthermore, physiological changes caused by these treatments in host cells were characterized by POX labeling methods with SDS-Page electrophoresis. Differences in expression of the POX and protein bands were observed in tissues of plants treated with different inducers. POX activity was determined by the presence of three strong bands in plant extract-treated leaves, two strong bands and one very weak band of about 20.1 and 43 kDa were visible in ASM-treated leaves. Evidence is provided that ASM, as well as extract of H. helix are equally capable of inducing of resistance responses in M26 apple rootstock, which result in an increased resistance to E. amylovora—the fire blight pathogen. These findings demonstrate that both treatments have the ability to induce the activation of defense genes leading to the accumulation of structural and biochemical activities at strategic sites, and these can be associated with induction of resistance against fire-blight.     

Induced systemic protection against tomato late blight elicited by plant growth-promoting rhizobacteria

ABSTRACT Two strains of plant growth-promoting rhizobacteria (PGPR), Bacillus pumilus SE34 and Pseudomonas fluorescens 89B61, elicited systemic protection against late blight on tomato and reduced disease severity by a level equivalent to systemic acquired resistance induced by Phytophthora infestans or induced local resistance by chemical inducer beta-amino butyric acid (BABA) in greenhouse assays. Germination of sporangia and zoospores of P. infestans on leaf surfaces of tomato plants treated with the two PGPR strains, pathogen, and chemical BABA was significantly reduced compared with the noninduced control. Induced protection elicited by PGPR, pathogen, and BABA were examined to determine the signal transduction pathways in three tomato lines: salicylic acid (SA)-hydroxylase transgenic tomato (nahG), ethylene insensitive mutants (Nr/Nr), and jasmonic acid insensitive mutants (def1). Results suggest that induced protection elicited by both bacilli and pseudomonad PGPR strains was SA-independent but ethylene- and jasmonic acid-dependent, whereas systemic acquired resistance elicited by the pathogen and induced local resistance by BABA were SA-dependent. The lack of colonization of tomato leaves by strain 89B61 suggests that the observed induced systemic resistance (ISR) was due to systemic protection by strain 89B61 and not attributable to a direct interaction between pathogen and biological control agent. Although strain SE34 was detected on tomato leaves, ISR mainly accounted for the systemic protection with this strain.     

The effects of ultraviolet-B (UV-B: 290–320 nm) radiation on blister blight disease of tea (Camellia sinensis)

Sunlight is known to reduce the incidence of blister blight disease of tea, caused by Exobasidium vexans . The effects of the ultraviolet-B (UV-B: 290–320 nm) component of solar radiation on the disease and the development of E. vexans were studied in the field in Sri Lanka using UV-screening filter materials held over a commercial crop. Exclusion of UV-B radiation by Polyester, which reduces fluxes in the UV-B region by approximately 75–85%, increased both the number of translucent spots (immature sites of infection) and number of sporulating blisters (mature sites of infection), but it had little or no effect on the sporulation of the pathogen. When basidiospores were artificially inoculated on leaves, and were exposed to full or filtered solar radiation, their survival and germination increased when UV-B wavelengths were removed; significant differences were found 62 h after inoculation. However, UV-B did not affect the extension of germ tubes. This study indicates that the UV-B component of solar radiation plays an important role in the natural regulation of blister blight disease in the field.     

The development of tea blister caused by Exobasidium vexans in tea (Camellia sinensis) correlates with the reduced accumulation of some antimicrobial metabolites and the defence signals salicylic and jasmonic acids

Blister blight (causal agent, Exobasidium vexans) is an economically devastating disease of tea (Camellia sinensis). To determine what metabolite changes occur with tea blister that could be linked to disease progression, metabolomic approaches were used on E. vexans infected tea from a Darjeeling (India) plantation. Samples were classified according to disease phenotypes, i.e. either healthy or at one of three stages of disease progression. Initial metabolite fingerprinting using Fourier transform infrared (FTIR) spectroscopy indicated that metabolite changes could be related to disease stage. Electrospray ionization mass spectrometry (ESI‐MS) highlighted caffeine and flavonoid metabolism changes as disease progressed. High‐performance liquid chromatography (HPLC) with online photodiode array detection and electrospray ionization‐tandem mass spectrometry (HPLC‐PDA‐ESI/MSⁿ) was used to characterize the caffeine, flavan‐3‐ol, flavone and flavonol profiles. There were increases in quercetin and kaempferol glucosides, kaempferol triglycosides and some catechin‐class antioxidants, but also substantial reductions in apigenin and myricetin glycosides and, particularly, caffeine as disease progressed. The content of important defence hormones, salicylic acid and jasmonic acid, was also reduced in blister blight diseased samples. Thus, E. vexans infections perturb defence signalling and reduce many potentially antimicrobial compounds, such as caffeine, to aid disease progression.     

具有植物诱导抗病活性的先导化合物及其结构修饰

系统介绍了苯并噻二唑、2,6-二氯异烟酸、β-氨基丁酸和水杨酸这4类应用较广泛的植物诱导抗病激活剂的研究进展,并对其衍生物及其抗病活性进行了归纳总结,对其诱导抗性进行了讨论。     

Identification of tea foliar diseases and pest damage under practical field conditions using a convolutional neural network

Lesions of tea (Camellia sinensis) leaves are detrimental to the growth of tea crops. Their adverse effects include further disease of tea leaves and a direct reduction in yield and profit. Therefore, early detection and on-site monitoring of tea leaf lesions are necessary for effective management to control infections and prevent further yield loss. In this study, 1,822 images of tea leaves with lesions caused by three diseases (brown blight, Colletotrichum camelliae; blister blight, Exobasidium vexans; and algal leaf spot, Cephaleuros virescens) and four pests (leaf miner, Tropicomyia theae; tea thrip, Scirtothrips dorsalis; tea leaf roller, Homona magnanima; and tea mosquito bug, Helopeltis fasciaticollis) were collected from northern and central Taiwan. A faster region-based convolutional neural network (Faster R-CNN) was then trained to detect the locations of the lesions on the leaves and to identify the causes of the lesions. The trained Faster R-CNN detector achieved a precision of 77.5%, recall of 70.6%, an F1 score of 73.91%, and a mean average precision of 66.02%. An overall accuracy of 89.4% was obtained for identification of the seven classes of tea diseases and pests. The developed detector could assist tea farmers in identifying the causes of lesions in real time.     

Induced Systemic Resistance and Promotion of Plant Growth by Bacillus spp

ABSTRACT Elicitation of induced systemic resistance (ISR) by plant-associated bacteria was initially demonstrated using Pseudomonas spp. and other gram-negative bacteria. Several reviews have summarized various aspects of the large volume of literature on Pseudomonas spp. as elicitors of ISR. Fewer published accounts of ISR by Bacillus spp. are available, and we review this literature for the first time. Published results are summarized showing that specific strains of the species B. amyloliquefaciens, B. subtilis, B. pasteurii, B. cereus, B. pumilus, B. mycoides, and B. sphaericus elicit significant reductions in the incidence or severity of various diseases on a diversity of hosts. Elicitation of ISR by these strains has been demonstrated in greenhouse or field trials on tomato, bell pepper, muskmelon, watermelon, sugar beet, tobacco, Arabidopsis sp., cucumber, loblolly pine, and two tropical crops (long cayenne pepper and green kuang futsoi). Protection resulting from ISR elicited by Bacillus spp. has been reported against leaf-spotting fungal and bacterial pathogens, systemic viruses, a crown-rotting fungal pathogen, root-knot nematodes, and a stem-blight fungal pathogen as well as damping-off, blue mold, and late blight diseases. Reductions in populations of three insect vectors have also been noted in the field: striped and spotted cucumber beetles that transmit cucurbit wilt disease and the silver leaf whitefly that transmits Tomato mottle virus. In most cases, Bacillus spp. that elicit ISR also elicit plant growth promotion. Studies on mechanisms indicate that elicitation of ISR by Bacillus spp. is associated with ultrastructural changes in plants during pathogen attack and with cytochemical alterations. Investigations into the signal transduction pathways of elicited plants suggest that Bacillus spp. activate some of the same pathways as Pseudomonas spp. and some additional pathways. For example, ISR elicited by several strains of Bacillus spp. is independent of salicylic acid but dependent on jasmonic acid, ethylene, and the regulatory gene NPR1-results that are in agreement with the model for ISR elicited by Pseudomonas spp. However, in other cases, ISR elicited by Bacillus spp. is dependent on salicylic acid and independent of jasmonic acid and NPR1. In addition, while ISR by Pseudomonas spp. does not lead to accumulation of the defense gene PR1 in plants, in some cases, ISR by Bacillus spp. does. Based on the strains and results summarized in this review, two products for commercial agriculture have been developed, one aimed mainly at plant growth promotion for transplanted vegetables and one, which has received registration from the U.S. Environmental Protection Agency, for disease protection on soybean.     

Late blight (Phytophthora infestans (Mont) De Bary) development from potato seed-pieces treated with fungicides

Fungicides were applied as seed-piece treatments to control potato late blight, caused by Phytophthora infestans, US8, A2 biotype in controlled environment and field experiments. Efficacy of seed treatments for controlling late blight was examined under three disease development regimes simulated by artifical inoculation; (a) seed-borne infection, (b) transmission of infection resulting from spread during the seed-cutting operation, and (c) infection of foliage by aerial inoculation. Emergence of plants from the seed-borne infection was uniformly low (<40%) in controlled environment and field experiments. In controlled environment experiments some of the plants that emerged from fungicide-treated seed-pieces were infected with late blight. Following exposure of tuber surfaces to P infestans, emergence rates from seed-pieces treated with formulated products that included mancozeb in the formulation were comparable to the untreated and non-inoculated control in controlled environment and field experiments. Plants that emerged from non-inoculated seed-pieces treated with fungicides that contained active ingredients known to be effective against foliar late blight had lower percentage foliar infection after inoculation than the untreated control. Leaves close to the base of the stem had fewer infections than leaves attached at the mid region of the main stem, 14 days after inoculation, in some of the controlled environment studies. In contrast, field experiments conducted under conditions conducive to late blight development showed that none of the seed treatments applied to late blight-free seed-pieces delayed the onset and severity of late blight infection. In potato production areas at risk of early season late blight, seed treatments applied to healthy seed may confer limited protection against late blight between planting and the first scheduled applications of prophylactic foliar fungicides. © 1999 Society of Chemical Industry     

Activation of tomato plant defence responses against bacterial wilt caused by Ralstonia solanacearum using DL-3-aminobutyric acid (BABA)

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.     

Effects of benzothiadiazole and acetylsalicylic acid on β-1,3-glucanase activity and disease resistance in potato

Benzothiadiazole (BTH), as Bion WG50, and acetylsalicylic acid (ASA) treatments of potato foliage of field- and glasshouse-grown potato plants were compared for control of two foliar diseases, early blight ( Alternaria solani ) and powdery mildew ( Erysiphe cichoracearum ). The effect of these treatments on harvested tubers wound-inoculated with the dry rot fungus ( Fusarium semitectum ) was also evaluated. BTH (50 mg a.i. L⁻¹) gave almost complete control of both foliar pathogens on inoculated glasshouse-grown plants and reduced the severity of leaf spotting diseases (mainly early blight) in the field. BTH (100 mg a.i. L⁻¹) and ASA (400 mg a.i. L⁻¹) reduced the severity of dry rot in field-grown tubers in some post-harvest wound-inoculated treatments but not others and a similar reduction occurred with tubers inoculated post-harvest from BTH-treated plants grown under glasshouse conditions. BTH treatment increased β-1,3-glucanase activity in leaves > stem > tubers > stolons but not in roots. Increased enzyme activity was recorded for up to 45 days post-treatment.     

Determination of the role of salicylic acid and Benzothiadiazole on physico-chemical alterations caused by <Emphasis Type="Italic">Cucumber mosaic virus</Emphasis> in tomato

Shoe-string disease caused by Cucumber mosaic virus (CMV) is one of the major threats to tomato production worldwide. The alteration in some biochemical parameters in leaves of the susceptible tomato genotype (Nagina) associated with CMV infection and the effect of exogenous application of salicylic acid (SA) and benzothiadiazole (BTH) were studied in this paper. Results showed that exogenous treatment with SA and BTH not only led to plants which gave significantly more yield than diseased controls (DC), but also delayed symptom expression and reduced disease severity. Analysis of biochemical parameters indicated that exogenous application of elicitors and viral infection, significantly affected the activity of peroxidase (POD), superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX). Compared to the DC plants, minimum disease severity and maximum number of fruit were recorded after a single dose of SA + BTH. Maximum plant height was recorded after weekly application of SA and maximum fruit yield per plant was gained with single dose of SA. Moreover, the activity of POD was significantly elicited many-fold after weekly application of SA + BTH, while higher amount of SOD was recorded with single dose of SA. The activity of CAT was also significantly accelerated after weekly application of SA + BTH while increased level of APX was noticed with single dose of BTH. In conclusion, the combined application of SA and BTH played an important role in induction of defense mechanism against CMV infection and can be useful in tomato disease management programs.     

An antibiotic fusaricidin: a cyclic depsipeptide from Paenibacillus polymyxa E681 induces systemic resistance against Phytophthora blight of red-pepper

In this study fusaricidin, a cyclic depsipeptide isolated from Paenibacillus polymyxa E681 (E681), was demonstrated to control Phytophthora blight infection caused by Phytophthora capsici in red-pepper. The minimal inhibitory concentration (MIC) of fusaricidin was found to be 16 ppm against P. capsici. The disease severity of P. capsici was 40% at 0.1 ppm of fusaricidin when compared with water-treated control (81.7%) on post-treatment, whereas the disease severities on pre-treatment were 45% and 83.3% in fusaricidin (0.1 ppm) and water-treated control, respectively, in red-pepper plants. Significant (P?<?0.05) disease suppression was observed on treatment with fusaricidin (0.1 ppm) by foliar spray and soil drench. The disease severity was drastically reduced to 3.3% by soil drench of fusaricidin (1.0 ppm), whereas in water-treated control, the disease severity was 83.3% in the first experiment. Fusaricidin at 0.1 ppm reduced disease severity of P. capsici to 27.5% when compared with positive control (43.1%) and water-treated control (66.2%) in the second experiment. Soft rot disease in tobacco was suppressed upon treatment with fusaricidin at 1.0 ppm by leaf infiltration. RT-PCR analyses of Arabidopsis thaliana revealed that there was an up-regulation of pathogenesis-related (PR) gene expression in wild type A. thaliana (Col-0), while there was no accumulation of PR genes, which implies that the mechanism of protection might be based on a salicylic acid-dependent pathway. This is the first report that fusaricidin exhibits protection against plant pathogens in addition to activity as an antibiotic agent. Hence, E681 can play a role in plant protection by secretion of ISR elicitors including fusaricidin.     

Salicylic Acid Induces Resistance to Alternaria solani in Hydroponically Grown Tomato

ABSTRACT Alternaria solani is the causal agent of early blight disease in tomato and is responsible for significant economic losses sustained by tomato producers each year. Because salicylic acid (SA) is an important signal molecule that plays a critical role in plant defense against pathogen invasion, we investigated if the exogenous application of SA would activate systemic acquired resistance (SAR) against A. solani in tomato leaves. The addition of 200 muM SA to the root system significantly increased the endogenous SA content of leaves. Free SA levels increased 65-fold over basal levels to 5.85 mug g(-1) fresh weight (FW) after 48 h. This level of SA had no visible phytotoxic effects. Total SA content (free SA + SA-glucose conjugate) increased to 108 mug g(-1) FW after 48 h. Concomitant with elevated SA levels, expression of the tomato pathogenesis-related (PR)-1B gene was strongly induced within 24 h of the addition of 200 muM SA. PR-1B expression was still evident after 48 h; however, PR-1B induction was not observed in plants not receiving SA treatment. Challenge inoculation of SA-treated tomato plants using conidia of A. solani resulted in 83% fewer lesions per leaf and a 77% reduction in blighted leaf area as compared with control plants not receiving SA. Our data indicate that root feeding 200 muM SA to tomato plants can (i) significantly elevate foliar SA levels, (ii) induce PR-1B gene expression, and (iii) activate SAR that is effective against A. solani.     

Antagonism between acibenzolar-S-methyl-induced systemic acquired resistance and jasmonic acid-induced systemic acquired susceptibility to Colletotrichum orbiculare infection in cucumber

In cucumber, we show salicylic acid only induce local acquired resistance (LAR), whereas acibenzolar-S-methyl (ASM) can induce LAR and systemic acquired resistance (SAR) to plant diseases. Jasmonic acid (JA) can induce local acquired susceptibility (LAS) and systemic acquired susceptibility (SAS). ASM treatment of lower first leaves leads to the accumulation of cucumber acidic class III chitinase (CHI2) in untreated upper leaves and effectively suppresses lesion formation on those leaves. In contrast, JA treatment completely suppresses CHI2 gene expression and causes plants to be more susceptible to Colletotrichum orbiculare. ASM-induced SAR can effectively antagonize the JA-induced SAS, providing a response that is midway between what would be expected with either JA or ASM by themselves.     

Web Blight of Fan Columbine, <Emphasis Type="Italic">Aquilegia flabellata, </Emphasis>Caused by <Emphasis Type="Italic">Rhizoctonia solani </Emphasis>AG1-IB : A New Disease Record

A new disease, found on fan columbine in August of 1997, first appeared as necrotic spots on leaves and within a week caused wilting of all the leaves. Fungal mycelia bound aerial parts of the plants together, formed mats of mycelia and eventually killed the plants. The pathogen, isolated from the infected leaves and stalks, was identified as Rhizoctonia solani AG1-IB in respect to hyphal anastomosis and culture types. The common name of web blight is proposed for this new occurrence on fan columbine (Kumonosu-byo in Japanese). Received 24 November 1999/ Accepted in revised form 4 February 2000     

First report of coriander leaf blight diseases caused by Cladosporium tenuissimum in China and analysis of metabolic alterations related to pathogenic processes

Coriander (Coriandrum sativum) is a medicinal and aromatic plant. From November 2017 to March 2020, leaf blight disease on coriander plants was frequently observed in commercial coriander cultivated fields of Haikou, Sanya and Wanning City, Hainan Province, China. Leaves with symptoms showed irregular chlorotic to dark brown necrotic lesions at the edges of leaves, and the leaves were curled and covered with a layer of grey mould. Based on morphological characteristics, pathogenicity testing and concatenated sequences of the internal transcribed spacer region (ITS), actin (ACT) and translation elongation factor-1α (TEF) genes, the pathogen was identified as Cladosporium tenuissimum. Untargeted metabolomes of the coriander leaves were analysed by gas chromatography-mass spectrometry (GC-MS). Score plots of principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) showed clear discrimination between infected and control treatments. The levels of l -threonic acid, hexadecanoic acid and myo-inositol in the control treatment were 3.45-, 1.81- and 2.44-fold, respectively, those in the infected treatment. To our knowledge, this is the first report of C. tenuissimum causing coriander leaf blight disease in China. Furthermore, this study indicates that C. tenuissimum infection of coriander causes a significant decrease in l -threonic acid, hexadecanoic acid and myo-inositol levels, indicating that these metabolites may be involved in the plant's response to coriander leaf blight disease.     

安徽省茶树细菌性梢枯病病原鉴定

2017年-2018年在安徽省庐江、东至县茶园种植区发现一种茶树新病害——梢枯病,发病症状表现为顶芽枯死,嫩叶叶柄变褐,叶片枯萎。为明确庐江、东至县茶树梢枯病的病原菌,采用平板划线法和稀释涂布平板法分离病原,按照柯赫氏法则对病原细菌进行致病性测定,并利用细菌的表型特征和分子生物学技术确定病原菌的分类地位。结果表明,从茶树患病叶片和茎干分离到菌落形态一致的细菌菌株共16株,选择6株代表性菌株进行回接试验,确定获得的细菌分离物为该病害的致病菌;通过对测试菌株的生理生化试验、16S rDNA和16S-23S rDNA-ITS的序列分析,以及基于16S rDNA、16S-23S rDNA-ITS序列的系统发育树分析,将安徽省茶树梢枯病的病原菌鉴定为燕麦嗜酸菌燕麦亚种Acidovorax avenae subsp.avenae。