Big Bud Research Articles

Can Pest Management and Cultivar Affect Phytoptus avellanae Infestations on Hazelnut?

The big bud mite Phytoptus avellanae is a resurgent pest of hazelnut, Corylus avellana, causing substantial yields reductions in many productive areas. Mites colonise and develop within healthy buds which become swollen, with subsequent alteration to the plant's development. To date, there has been limited knowledge on how the cultivar and pest management strategies affect infestations. This study explored these aspects through two ad hoc experiments carried out in central Italy. In the first experiment, the susceptibility of 11 cultivars with different geographic origins was tested in a germplasm hazelnut collection. The second experiment assessed the infestation level in orchards with integrated pest management (IPM) and organic pest management strategies and in a renaturalised environment (a former agricultural area now converted in a natural park). The results showed that the most and the least susceptible cultivars were Tonda Gentile and Nocchione, respectively. No significant differences were found between IPM and organic management, but they were both different to the renaturalised environment. The outcomes of this research can serve as a valuable reference and can be applied to all current or potential hazelnut cultivation areas characterised by the same environmental conditions.

Genomic and Pathogenic Characterization of Akanthomyces muscarius Isolated from Living Mite Infesting Hazelnut Big Buds.

The capability of entomopathogenic fungi to live as plant endophytes is well established. However, their presence in undiscovered environmental niches represents the beginning of a new challenging research journey. Recently, Akanthomyces muscarius (Ascomycota, Cordycipitaceae) (Petch) Spatafora, Kepler & B. Shrestha was isolated from hazelnut buds infested by the big bud mite pest Phytoptus avellanae Nalepa, which makes the buds swollen, reddish, and unable to further develop. Gall formation is known to be regulated by a consortium of microbes and mites, and to better understand the possible role of A. muscarius within the infested gall, its whole genome sequence was obtained using a hybrid approach of Illumina and Nanopore reads. The functional and comparative genomics analysis provided within this study may help answer questions related to the ecology and the entomopathogenicity of this fungus.

First report of Candidatus Phytoplasma australasia (16SrII- subgroup D) associated with virescence of Chia (Salvia hispanica L.) from India.

Chia (Salvia hispanica L., Lamiaceae) is an important commercial and medicinal crop recently popularized in India and widely cultivated in Karnataka (Joy et al., 2022). During the field survey of chia crop diseases, characteristic virescence like symptoms were observed at Main Agricultural Research Station, UAS, Raichur as well as at Mysuru and HD Kote region. The incidence was ranged from 2 - 4 per cent in an area of 30 hectares. Typical symptoms associated with chia are malformed shoot and/or inflorescence axis with reduced floral parts with greenish florets. The stem axis become thick, flattened, leaves are reduced towards terminal region. A total of five phytoplasma suspected samples and five suspected healthy samples were used for identification purpose. The Plant Genomic DNA Miniprep Kit (Sigma Aldrich, USA) was used to extract the DNA from five symptomatic and five asymptomatic samples and the DNA was used as template to amplify the phytoplasma-specific 16S rDNA gene using P1/P7 primers (Deng and Hiruki, 1991; Schneider et al., 1995) followed by nested PCR using R16F2n/R16R2 primers (Gundersen and Lee 1996). The expected 1.25-kb amplicon was detected from the suspected symptomatic samples. Nested PCR products were purified and sequenced from both the directions using ABIX370 Genetic Analyzer (Applied Biosystems, Waltham, MA). The analysis revealed that all five sequences shared 100 per cent identity with Candidatus Phytoplasma aurantifolia (OM649850, ON975012) and Tomato big bud phytoplasma (EF193359). The in-silico RFLP pattern of F2n/R2 primed region of 16S rDNA gene analyzed by using iPhyClassifier (Zhao et al. 2009) revealed that the sequence shared 98.72 per cent nucleotide sequence similarity with coefficient value of 1.00 to the reference strain RFLP pattern of 16Sr group II, subgroup D (witches'-broom disease of lime; U15442). Based on 16SrDNA sequences and in-silico RFLP analysis, the phytoplasma associated with the chia virescence was identified as a member of 16SrII-D group. Further, SecA gene was also amplified from the samples using SecAfor1/SecArev3 primer pair (Hodgetts et al., 2008). All samples produced ~400 bp products and sequenced as detailed above. Sequence analysis by nBLAST revealed 100 per cent similarity to Ca. P. australasia (MW020545) and Ca. P. aurantifolia isolate Idukki Kerala 1 (MK726369) both representing 16SrII-D group phytoplasma. The representative sequence (16Sr: PP359693, PP359694; secA:PP386558, PP386559) were deposited in GenBank. Chia virescence phytoplasma belonging to Ca. phytoplasma australasia has not been reported anywhere. The phytopathological studies associated with chia crop are very limited. Joy et al. (2022) reported the occurrence of foot rot disease caused by Athelia rolfsii. Several hosts are recorded to be associated with 16SrII D phytoplasma which includes china aster, eggplant and crotalaria (Mahadevakumar et al., 2017, Yadav et al., 2016a, b). Now the wide occurrence of the phytoplasma in the area might have transmitted by vectors. The occurrence of virescence is of great importance as it affects the overall yield which reduces the market value. To our knowledge, this is the first report of a group 16SrII-D phytoplasma associated with chia virescence in India.

Differential Symptomology, Susceptibility, and Titer Dynamics Manifested by Phytoplasma-Infected Periwinkle and Tomato Plants.

Phytoplasmas are intracellular pathogenic bacteria that infect a wide range of plant species, including agriculturally important crops and ornamental trees. However, our understanding of the relationship between symptom severity, disease progression, and phytoplasma concentration remains limited due to the inability to inoculate phytoplasmas mechanically into new plant hosts. The present study investigated phytoplasma titer dynamics and symptom development in periwinkle and tomato, both infected with the same potato purple top (PPT) phytoplasma strain using a small seedling grafting approach. Virescence, phyllody, and witches'-broom (WB) symptoms sequentially developed in periwinkle, while in tomato plants, big bud (BB, a form of phyllody), cauliflower-like inflorescence (CLI), and WB appeared in order. Results from quantitative polymerase chain reaction (qPCR) targeting the PPT phytoplasma's 16S rRNA gene revealed that in both host species, phytoplasma titers differed significantly at different infection stages. Notably, the highest phytoplasma concentration in periwinkles was observed in samples displaying phyllody symptoms, whereas in tomatoes, the titer peaked at the BB stage. Western blot analysis, utilizing an antibody specific to PPT phytoplasma, confirmed substantial phytoplasma presence in samples displaying phyllody and BB symptoms, consistent with the qPCR results. These findings challenge the conventional understanding that phytoplasma infection dynamics result in a higher titer at later stages, such as WB (excessive vegetative growth), rather than in the early stage, such as phyllody (abnormal reproductive growth). Furthermore, the PPT phytoplasma titer was markedly higher in periwinkles than in tomato plants, indicating differing susceptibilities between the hosts. This study reveals distinct host responses to PPT phytoplasma infection, providing valuable insights into phytoplasma titer dynamics and symptom development, with implications for the future management of agricultural disease.

Spatial and Temporal Disparity Analyses of Glycosylated Benzaldehyde and Identification and Expression Pattern Analyses of Uridine Diphosphate Glycosyltransferase Genes in Prunus mume.

The species Prunus mume consists of uniquely aromatic woody perennials with large amounts of free aromatic substances in the flower cells. Uridine diphosphate glycosyltransferase (UGT) modifies these free aromatic substances into water-soluble glycoside-bound volatiles (GBVs) which play an important role in regulating the use of volatiles by plants for information exchange, defense, and stress tolerance. To investigate the changes in the glycosidic state of aromatic substances during the flowering period of P. mume and discern the location and expression of glycoside synthesis genes, we extracted and enzymatically hydrolyzed GBVs of P. mume and then utilized gas chromatography-mass spectrometry (GC-MS) to characterize and analyze the types and contents of GBV glycosides. Further, we identified and classified the members of the UGT gene family of P. mume using the bioinformatic method and analyzed the correlation between the expression of the UGT family genes in P. mume and the changes in glycosidic content. The results showed that the benzenoids were the main aromatic substance that was glycosylated during flowering in P. mume and that glycosidic benzaldehyde was the most prevalent compound in different flower parts and at different flowering stages. The titer of glycoside benzaldehyde gradually increased during the bud stage and reached the highest level at the big bud stage (999.6 μg·g-1). Significantly, titers of glycoside benzaldehyde significantly decreased and stabilized after flowering while the level of free benzaldehyde, in contrast, significantly increased and then reached a plateau after the flowering process was completed. A total of 155 UGT family genes were identified in the P. mume genome, which were divided into 13 subfamilies (A-E, G-N); according to the classification of Arabidopsis thaliana UGT gene subfamilies, the L subfamily contains 17 genes. The transcriptome analysis showed that PmUGTL9 and PmUGTL13 were highly expressed in the bud stage and were strongly correlated with the content of the glycosidic form of benzaldehyde at all stages of flowering. This study provides a theoretical basis to elucidate the function of UGT family genes in P. mume during flower development, to explore the mechanism of the storage and transportation of aromatic compounds in flower tissues, and to exploit industrial applications of aromatic products from P. mume.

Biology and management of big bud mites in Pacific Northwest (USA) hazelnut orchards

Biology and management of big bud mites in Pacific Northwest (USA) hazelnut orchards

Studies on Pollen Morphology, Pollen Vitality and Preservation Methods of Gleditsia sinensis Lam. (Fabaceae)

Gleditsia sinensis Lam. (Fabaceae) is an endemic species in China, which has a wide range of ecological functions and high economic value. G. sinensis belongs to androdioecy, and the stamens of perfect flowers are aborted, meaning that a perfect flower is a functional female flower. Understanding the dynamic process of flowering and the characteristics of pollen morphology effectively determine the viability of pollen vitality, and the suitable conditions for short-term storage of pollen can provide theoretical basis and technical reference for hybrid breeding and germplasm conservation of G. sinensis. In this study, the male plants of G. sinensis in Guiyang area were used as research materials. The flowering dynamic process of male flowers was recorded through field observation. The morphology of pollen was observed and analyzed with a scanning electron microscope (SEM). The germination characteristics of pollen were studied with an in vitro germination method, and the pollen vitality was also determined using four staining methods. The effects of different storage temperatures and water contents on pollen germination rate were discussed. The results showed that the male flowers of G. sinensis had a short, single flowering period, lasting 2–3 days from the opening to the shedding. The dynamic opening process of a single flower was artificially divided into five stages. Pollen grains of G. sinensis are oblate spheroidal, tricolporate with equatorial elongated endoapertures and the sporoderm surface is reticulate. The MTT (Thiazolyl Blue Tetrazolium Bromide) staining method could accurately and quickly determine the pollen vitality of G. sinensis. The highest pollen germination rate was 65.89% ± 3.41%, and the length of the pollen tube was 3.96 mm after cultured in 15% sucrose + 100 mg/L boric acid + 20 mg/L calcium chloride for 24 h. It was necessary to collect the pollen at the big bud stage, which was conducive to improving the efficiency of pollen collection because the pollen had been mature with high pollen vitality at this stage. When it came to pollen preservation, the pollen germination rate was significantly affected by storage time, storage temperature and pollen water content. The pollen still had high vitality after being stored at −80 °C for 30 days when the moisture content of the pollen decreased to 9%, and the pollen germination rate only decreased by 28.84% compared with that before storage. In conclusion, this study has comprehensively and systematically studied the morphology, vitality determination and preservation methods of the pollen of G. sinensis, providing a theoretical basis for the cross regional breeding and the conservation and utilization of germplasm resources.

USED NASTED-PCR DETECTION OF PHYTOPLASMA CAUSING BIG BUD DISEASE ON TOMATO IN IRAQ

Symptoms similar to those produced by the phytoplasma disease "Big bud" were observed on tomatoes (Solanum lycopersicum L.) grown in the field in Mosul city, Iraq. Diseased plants were characterized by twisting, corrugated, yellowing or reddening of leaves. The sepals of the flowers acquired hypertrophied form, were fused together and created a bell-shaped sterile bud (phyllody) of green or anthocyanin color. The stems of the plants were lignified, and phloem necrosis was observed on the stem. In mid-September 2020, samples of 30 diseased and 2 healthy (control) tomato plants were collected from the fields. Phytoplasmas were detected by PCR and Nested-PCR in 10 diseased samples, use universal and specific primers. The results of a phylogenetic tree consisting of 27 genetic sequences of the 16 S ribosomal RNA gene of Candidatus Phytoplasma trifolii, locally isolated from Iraq/Mosul, showed a sequence identity with a high percentage of genetic similarity of 99% with Candidatus Phytoplasma trifolii 16Sr member VI-A. Clover proliferation group (16Sr VI), with various isolates from around the world.

Monitoring the Bud Mite Pest in a Hazelnut Orchard of Central Italy: Do Plant Height and Irrigation Influence the Infestation Level?

Mite pests are a serious threat for hazelnut cultivations, causing economic losses every year. At least two species of big bud mites, Phytoptus avellanae (Acari: Phytoptidae) and Cecidophyopsis vermiformis (Acari: Eriophyidae), are involved in severe hazelnut bud infestations, even though few studies report P. avellanae as the most present and harmful. Great steps forward have been made in monitoring and management strategies of these mite pests, but a plethora of questions remains unanswered about their ecology and behaviour and how agronomical practices impact populations. Given this precondition, we conducted a four-year monitoring in an experimental hazelnut orchard located in the Viterbo hazelnut district, Central Italy, to: (i) explore the potential effect that irrigation has on mite infestations, (ii) assess if mites locate in a particular band height of hazelnut plants; and (iii) assess the overall field infestation over the years. This study showed that not-irrigated plants and plants irrigated by underground pipe systems were similarly infested. Mites tend to locate in the middle band of the plant, namely from 1.5 to 3 m from the ground. The four-year survey showed an overall increasing infestation trend, with a peak in 2021 for irrigated plants and 2022 for not-irrigated. These results are a milestone for further exploration of the biology and ecology of this pest and to formulate ad hoc monitoring and control strategies as well.

Study of elite black currant varieties selected at the Federal Agrarian Scientific Centre of the North-East

Elite varieties of black currant selected at the Federal Agrarian Scientific Centre of the North-East were studied with the purpose of identifying samples with an optimal combination of high productivity, large fruit, good taste, resistance to big bud mite and powdery mildew. The studies were carried out in 2015–2019 on a site located in the central agro-climatic zone of the Kirov region. 10 elite black currant varieties of 2013 planting were investigated. The varieties of Arkadiya and Vologda were used as control. The counts and observations were carried out using conventional methods. The combination of high productivity, its sustainability and high self-fertility was noted in varieties 71-2-07, 65-1-07 and 64-4-07. In terms of resistance to the pest, two highly resistant samples 71-2-07 and 65-1-07 were identified, which showed no signs of damage during the study period. The damage by big bud mite remained low across the entire experimental site. The average negative effect of big bud mite on the yield was found (r = -0.48). In the following 7 elite forms — 71-2-07, 65-1-07, 70-5-07, 46-1-07, 12-1-07, 15-1-07, 20-1-07 (70.0 % of the studied material), the maximum degree of damage by powdery mildew did not exceed 1.0 points, which indicates their high resistance. The combination of high resistance to big bud mites and resistance to powdery mildew was found in varieties 71-2-07 and 65-1-07. During the study period, 9 elite black currant varieties produced large-fruited berries. Out of these 9 forms, 3 (71-2-07, 64-4-07, 12-1-07) showed significantly higher values of this indicator compared to the Vologda control. Sample 27-1-07 was distinguished by a combination of large fruit, good taste and low acidity, as well as by high contents of ascorbic acid and dry matter. Sources of economically valuable traits were identified in 2 samples: 65-1-07 having a combination of high productivity, large fruit, high self-fertility, good taste, resistance to big bud mites and powdery mildew; 64-4-07 having a combination of high productivity, large fruit and high self-fertility. These genotypes can be recommended as a starting material for further breeding. On the basis of the results obtained, the Ariel variety (71-2-07) was forwarded to the State Variety Testing in 2020.

History and Current Status of Phytoplasma Diseases in the Middle East.

Simple SummaryPhytoplasmas are microorganisms that have been reported to be associated with hundreds of plant diseases in most parts of the world. Several reviews were published regarding diseases associated with phytoplasmas in different countries. However, no comprehensive review is available on the phytoplasma diseases in the Middle East, which is an important region with arid to semi-arid conditions. This review describes the most common phytoplasmas that are associated with diseases in this part of the world. It also describes some of the insect vectors that help to transmit these phytoplasmas. Information is also presented regarding the distribution of the diseases and host ranges.Phytoplasmas that are associated with fruit crops, vegetables, cereal and oilseed crops, trees, ornamental, and weeds are increasing at an alarming rate in the Middle East. Up to now, fourteen 16Sr groups of phytoplasma have been identified in association with more than 164 plant species in this region. Peanut witches’ broom phytoplasma strains (16SrII) are the prevalent group, especially in the south of Iran and Gulf states, and have been found to be associated with 81 host plant species. In addition, phytoplasmas belonging to the 16SrVI, 16SrIX, and 16SrXII groups have been frequently reported from a wide range of crops. On the other hand, phytoplasmas belonging to 16SrIV, 16SrV, 16SrX, 16SrXI, 16SrXIV, and 16SrXXIX groups have limited geographical distribution and host range. Twenty-two insect vectors have been reported as putative phytoplasma vectors in the Middle East, of which Orosius albicinctus can transmit diverse phytoplasma strains. Almond witches’ broom, tomato big bud, lime witches’ broom, and alfalfa witches’ broom are known as the most destructive diseases. The review summarizes phytoplasma diseases in the Middle East, with specific emphasis on the occurrence, host range, and transmission of the most common phytoplasma groups.

Multilocus sequence analysis of Candidatus Phytoplasma aurantifolia associated with phyllody disease of gerbera from India.

Gerbera is the most popular cut flower known for its variety of colors and is grown across the world. Its production is challenged by numerous diseases affecting production and quality. During our survey, ten samples from the gerbera plants exhibiting phyllody disease symptoms were collected from Bangalore Rural District, Karnataka, India. The association of phytoplasma with the gerbera phyllody samples was confirmed by PCR using 16SrRNA, SecY, Ribosomal protein (rp) and SecA gene-specific primers. PCR products were amplified from all ten gerbera plants using phytoplasma-specific primers. The amplified PCR products were cloned and sequenced; the sequences of the ten clones were identical. Therefore, representative isolate (GePP1, Gerbera phyllody phytoplasma) was selected for further analysis. The sequence analysis showed that GePP1 shared maximum nucleotide (nt) identity of 97.1% (16SrRNA) with Eggplant big bud, 98.7 to 98.8% (SecY gene) with Tomato big bud, 99.2 to 99.6% (rp gene) with Alfalfa witches-broom (EF193371) and 99.1% (SecA gene) with Sesame phyllody phytoplasmas and that it belongs to the Ca. P. aurantifolia (16SrII) group. This result was well supported by the phylogenetic analysis showing GePP1 (16Sr RNA, SecY, rp and SecA genes) closely clustering with the Ca. P. aurantifolia 16SrII group isolates reported so far. The virtual RFLP pattern generated for the phytoplasma from gerbera was different (similarity coefficient 0.89) from the reference pattern of Ca. P. aurantifolia (16Sr II) subgroup after analysis with four enzymes (BfaI, Hha1, Sau3AI and RsaI). Based on the threshold similarity coefficient for a new subgroup (delineation should be set at 0.97), the GePP1 may be considered as new subgroup of Ca. P. aurantifolia (16SrII) group. This is the first report of Ca. P. aurantifolia belonging to 16Sr II group affecting gerbera in India. Keywords: Candidatus Phytoplasma aurantifolia; phyllody; gerbera; PCR; phylogenetic analysis.

Emerging incidence of tomato big bud disease associated with a 16srii-d phytoplasma in Andhra Pradesh and odisha states of India

Emerging incidence of tomato big bud disease associated with a 16srii-d phytoplasma in Andhra Pradesh and odisha states of India

Interaction between ‘Candidatus Phytoplasma australasiae’ and Tomato yellow leaf curl virus in tomato plants

To evaluate the effect of mixed infection of two main pathogens of tomato in Iran, the interaction between tomato big bud phytoplasma (TBBP, 16SrII-D) and Tomato yellow leaf curl virus (TYLCV) was investigated under greenhouse condition. Tomato plants were graft-inoculated either with TBBP or TYLCV alone or together simultaneously and non-simultaneously. Symptoms expression and incubation period of the diseases were evaluated on all inoculated plants. To assess pathogen development, the concentrations of TBBP and TYLCV were compared at 10, 20, 40 and 70 days post-inoculation using quantitative PCR assays. In all replications, the tomato plants doubly inoculated with TBBP + TYLCV showed milder symptoms and longer incubation period than those singly inoculated with TBBP or TYLCV. Results also showed a reduction of TYLCV and TBBP concentrations in doubly inoculated plants when compared to single infection, although these reductions were not always statistically significant. In the tomato plants simultaneously inoculated with TBBP and TYLCV, the phytoplasma and virus concentrations were significantly lower at 70 days post-inoculation. These results suggest an antagonism between TYLCV and TBBP when infecting the tomato plant.

First Report of Tomato “Big Bud” Disease in Syria Caused by ‘Candidatus Phytoplasma trifolii’-Related Strain

HomePlant DiseaseVol. 103, No. 3First Report of Tomato “Big Bud” Disease in Syria Caused by ‘Candidatus Phytoplasma trifolii’-Related Strain PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Tomato “Big Bud” Disease in Syria Caused by ‘Candidatus Phytoplasma trifolii’-Related StrainH. Khalil, R. N. Yousef, N. V. Girsova, D. Z. Bogoutdinov, T. B. Kastalyeva, and S. AldenkaweH. KhalilAl-Baath University, Homs, Syria; Search for more papers by this author, R. N. YousefAl-Baath University, Homs, Syria; Search for more papers by this author, N. V. GirsovaAll-Russian Research Institute of Phytopathology, Bolshie Vyasiomy, Moscow Region, 143050 Russia; and Search for more papers by this author, D. Z. BogoutdinovSamara State Agricultural Academy, Ust’-Kinel’sky, Samara Province, 446442 RussiaSearch for more papers by this author, T. B. Kastalyeva†Corresponding author: T. B. Kastalyeva; E-mail: E-mail Address: kastalyeva@yandex.ruhttp://orcid.org/0000-0003-3978-9419All-Russian Research Institute of Phytopathology, Bolshie Vyasiomy, Moscow Region, 143050 Russia; and Search for more papers by this author, and S. AldenkaweAl-Baath University, Homs, Syria; Search for more papers by this authorAffiliationsAuthors and Affiliations H. Khalil1 R. N. Yousef1 N. V. Girsova2 D. Z. Bogoutdinov3 T. B. Kastalyeva2 † S. Aldenkawe1 1Al-Baath University, Homs, Syria; 2All-Russian Research Institute of Phytopathology, Bolshie Vyasiomy, Moscow Region, 143050 Russia; and 3Samara State Agricultural Academy, Ust’-Kinel’sky, Samara Province, 446442 Russia Published Online:21 Jan 2019https://doi.org/10.1094/PDIS-06-18-1057-PDNAboutSectionsSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Symptoms similar to the phytoplasma disease “big bud” have been observed on tomatoes (Solanum lycopersicum L.) grown in the field in the central and north-eastern part of Syria since 2013. Diseased plants were characterized by twisting, corrugated, yellowing, or reddening leaves. The sepals of the flowers acquired hypertrophied form, were fused, and created a bell-shaped sterile bud: phyllody of green or anthocyanin color. The stems of the plants were lignified, and necrosis of the phloem was observed on stem cuts. Incidence of the disease varied between 0.2 and 40%, depending on the region and weather conditions. An infected plant formed on average 70% less fruit than a healthy plant. In mid-September 2017, samples of 12 infected and two healthy (control) tomato plants (cv. Sheruk) collected in the Syrian province of Homs were transferred to the All-Russian Research Institute of Phytopathology (Russia), where an identification of phytoplasma was carried out. Total DNA was extracted from 0.3 g of leaf mid veins according to the method of Maixner et al. (1995). A nested polymerase chain reaction (PCR) was performed to detect phytoplasmas. Primers P1/16S-SR were used for the first amplification, followed by the second amplification with primers R16F2n/R16R2. The 20-fold diluted PCR product of the first amplification was used as the DNA template for the second amplification, resulting in the amplification of a 1.2-kb amplicon. The positive control included DNA isolated from the previously known phytoplasma-infected sample, and the negative control PCR reaction lacked a DNA template. Eleven of the 12 symptomatic plants amplified the expected 1.2-kb band in the nested PCR. All PCR products were subjected to the restriction fragment length polymorphism analysis (RFLP) and were digested by restriction enzymes AluI, HhaI, MseI (Tru1I), RsaI, Sau3AI, and TaqI. The electrophoretic profiles of the products digested were compared with published real and virtual profiles of phytoplasmas (Lee et al. 1998; Wei et al. 2007). All 11 profiles for each endonuclease were identical to each other and to RFLP profiles for clover proliferation phytoplasma group 16SrVI, subgroup 16SrVI-A. In 2011, there was the first report of phytoplasma isolated from grapevine in Syria and identified as belonging to 16SrXII group in mixture with phytoplasma of 16SrVI group (Contaldo et al. 2011). In 2013, phyllody disease of sesame with numerous different symptoms such as floral virescence, phyllody, witches’ broom, yellowing, short internodes, and twisted and reduced leaves was described in Syria (Khabbaz et al. 2013). It was shown that the causative agent was phytoplasma, but its group was not determined. To our knowledge, this is the first report of a 16SrVI group phytoplasma infecting tomatoes in Syria and ‘Candidatus Phytoplasma trifolii’ as the most probable pathogen species.

Detection of phytoplasma causing tomato big bud disease in Syria

Detection of phytoplasma causing tomato big bud disease in Syria

First Hungarian records of Aprostocetus eriophyes, an acariphagous chalcidoid wasp (Hymenoptera: Eulophidae)

Aprostocetus eriophyes (Taylor, 1909) (Hymenoptera: Eulophidae) is reported as new to the Hungarian fauna. Female specimens were reared from galls of the hazelnut big bud mite (Phytoptus avellanae Nalepa, 1889) (Phytoptidae) collected in February to April 2017 at six different locations in Hungary. Diagnosis, hosts, biology and distribution of A. eriophyes is discussed. With 3 figures.

Detection of Phytoplasmas Associated with Tomato Witches’ Broom and Big Bud Disease in Egypt

Symptoms of witches’ broom were observed on tomato plants in some fields in Aswan governorate, Egypt. Molecular investigation was done with phytoplasma-detection primer P1/P7 to amplify a fragment of the 16S rRNA gene plus spacer region and beginning of 23Sr gene. RFLP analyses and sequencing of DNA fragments amplified by R16F2n/R2 primers indicated that these phytoplasmas are closely related and could be classified in the 16SrII group. Phylogenetic analyses of 41 accessions of 16S ribosomal RNA gene sequences of ‘Candidatus phytoplasmas’ comprising the strain from Egypt and representative strains from GenBank confirmed that the phytoplasma from tomato cluster with other strains all classified in subgroup 16SrII-D. Therefore, it could be useful to use the RFLP methodology in rapid and specific screenings of this phytoplasma presence in Egyptian tomato plants

Increasing incidence of tomato big bud phytoplasma in Ranga Reddy District of Telangana State, India

Tomato is an important vegetable crop and India ranks second in area and production of tomato worldwide. During field surveys in Moinabad and Shamshabad Mandals in Ranga Reddy district of Telangana from 2014–2016, symptoms like big bud and phyllody were observed on tomato. The affected plants did not produce any fruit. The phytoplasma strains were detected and characterized using universal and nested primer pairs of phytoplasma with amplification of 16S rRNA and secA genes. BLAST analysis of 1.25 kb 16S rDNA partial sequences of nested PCR products and 880 bp of secA gene products obtained from symptomatic TBB (tomato big bud) samples revealed 99% sequence identity with strains of ‘Ca. Phytoplasma australasia’ (16Sr II group). Phylogenetic analysis and virtual RFLP analysis of 16SrDNA sequences of tomato big bud phytoplasma (TBBP) strain also suggested the closest relationship with ‘Ca. P. australasia’16Sr II-D subgroup related strain. Present study confirmed association of 16Sr II-D subgroup of phytoplasma associated with tomato big bud disease in Telangana State of India.

Occurrence, identification and transmission of the phytoplasma associated with tomato big bud disease and identification of its vector and weed host in Pakistan

Tomato (Solanum lycopersicum L.) plants showing stunting, big bud, leaves yellowing or reddening and witches’-broom symptoms were observed since 2009 in Pakistan. A weed Parthenium hysterophorus grown in and around tomato fields also exhibited witches’-broom like symptoms. Fluorescence light microscopy of hand-cut stem stalk sections treated with Dienes’ stain showed blue areas in the phloem region of both tomato and P. hysterophorus symptomatic plants that indicated the association of phytoplasma with the complex. Amplification of 1.2 kb 16S rDNA fragment in nested PCR confirmed that the symptomatic tomato and P. hysterophorus plants are infected by a phytoplasma. Partial sequencing of 16S rRNA (GenBank accession: LT671581 and LT671583) and virtual restriction fragment length polymorphism confirmed that the phytoplasma associated with both plant species had the greatest homology to 16SrII-D subgroup. Disease was successfully transmitted by grafting and leafhopper Orosius albicinctus in tomato plants. This is the first report of natural occurrence of 16SrII-D phytoplasma in tomatoes and a weed P. hysterophorus in Pakistan.