• The Plant Pathology Journal
• /
• 제28권3호
• /
• pp.239-247
• /
• 2012

Phytoplasmas have been associated with more than 46 plant species in Korea. Several vegetables, ornamentals, fruit trees and other crop species are affected by phytoplasma diseases. Six 16Sr groups of phytoplasmas have been identified and these phytoplasmas are associated with 63 phytoplasma diseases. Aster yellows phytoplasmas are the most prevalent group and has been associated with more than 25 diseases in Korea. Jujube witches' broom, paulownia witches' broom and mulberry dwarf diseases cause economic losses to host trees throughout the country. So far, Korean phytoplasmas belong to six species of 'Candidatus Phytoplasma'; 'Ca. P. asteris', 'Ca. P. pruni$^*$', 'Ca. P. ziziphi', 'Ca. P. trifolii', 'Ca. P. solani$^*$' and 'Ca. P. castaneae'. The diseases are distributed throughout the country and most of them were observed in Gyeongbuk and Chonbuk provinces. At least four insect vectors; Cyrtopeltis tenuis, Hishimonus sellatus, Macrosteles striifrons and Ophiola flavopicta have been identified for phytoplasma transmission.

• The Plant Pathology Journal
• /
• 제25권1호
• /
• pp.21-25
• /
• 2009

Jujube trees infected with phytoplasma exhibit symptoms of typical witches' broom, such as yellowing, abnormally small leaves, short internodes and proliferation of shoots. A 1.2 kb fragment of the 16S rDNA from jujube phytoplasma was generated by R16F2n/R16R2 primer pair from earlier amplified P1/P7 PCR products of cloned jujube witches' broom phytoplasmas. Enzymatic restriction fragment length polymorphism (RFLP) and sequence analysis of 16S rDNA revealed that the jujube tree was infected with 16S rDNA I and V groups of phytoplasmas. Extensive comparative analyses of restriction enzyme profiles from Alu I, Hha I, Msp I, and Rsa I clearly classified the two into different phytoplasma groups. The phylogenie analyses based on 16S rDNA showed that the similarity of the two different clones was 87.5%. This is the first report of a mixed phytoplasmal infection in a single jujube tree.

• 한국산림과학회지
• /
• 제101권4호
• /
• pp.635-639
• /
• 2012

뽕나무 오갈병 파이토플라스마 매개곤충을 알아보기 위하여 뽕나무 재배지에서 채집된 곤충 중 흡즙성 곤충 3 종(Hishimonas sellatus, Bothrogonia japonica and Balclutha punctata)를 선발하였다. 이들 흡즙성 곤충을 뽕나무 이병주에서 흡즙시킨 다음 건전 뽕나무와 일일초로 전반시킨 결과, 마름무늬매미충(H. sellatus)과 B. punctata이 파이토플라스마를 전반하였다. 뽕나무에서는 전형적인 오갈 증상을 보였지만 일일초에서는 가지가 가늘게 늘어지며, 잎은 총생하고 작아지는 빗자루증상이 나타났다. 매개충과 매개전염시킨 뽕나무와 일일초에 대하여 R16F2n/R2 프라이머로 PCR 검정 결과 끝검은말매미충을 제외한 모든 시료에서 파이토플라스마가 검출되었다.

• The Plant Pathology Journal
• /
• 제21권4호
• /
• pp.383-386
• /
• 2005

In 2003 typical phytoplasma symptoms of witches' broom and flower malformation were observed on statice (Limonium sinuatum) plants grown at commercial greenhouses in Busan, South Korea. The DNA extracted from the infected leaves was amplified using universal primer pair of Pl/P6 derived from conserved 16S rRNA gene of Mollicutes giving the expected Polymerase chain reaction (PCR) product of 1.5 kb. In the nested PCR assays, the expected DNA fragment of 1.1 kb was amplified with the specific primer pair 16Fl/Rl that was designed on the basis of aster yellows (AY) phytoplasma 16S rDNA sequences. The 1.1 kb PCR products were cloned and nucleotide sequences were determined. The sequences were identical to that of Onion yellows OY phytoplasma (GenBank accession no. D12569) isolated from Onion in Japan. Electron microscopy of thin sections of leaf veins showed phytoplasma bodies in the phloem. Statice witches' broom symptom occurred on statice in commercial greenhouses in Korea was confirmed as infection of AY phytoplasma by transmission electron microscopy observation, and by determination of 16S rRNA gene sequences of phytoplasma.

• The Plant Pathology Journal
• /
• 제17권1호
• /
• pp.57-61
• /
• 2001

Phytoplasmas were identified from two chrysanthemum (Dendranthema grandiflorum) plants showing different symptoms ; one with stusting, rosette, and excessive branching (Ph-ch1), and the other with stunting and chlorosis (Ph-ch2). Electron microscopy of midrib of the plants with the symptoms revealed that numerous phytoplasmas were localized in the phloem cells. The disease was transmitted from infected plants to healthy ones by grafting. Phytoplasma-specific DNA was detected in polymerase chain reaction (PCR) analysis with template DNA extracted from the leaves of Ph-ch1 and Ph-ch2, both of which yielded a same DNA band corresponding to 1.5 kb. Using a specific primer pair (R16F1/R1) synthesized based on aster yellows (AY) phytoplasma, a DNA fragment of 1.1 kb was amplified by PCR. Endonuclease restriction patterns of the 1.1 kb PCR products from Ph-ch1 and Ph-ch2, which were dgeste with each of the restriction endonucleases Sau3A, Hha, Alu and Rsa, were same as those of AY phytoplasma from periwinkle. This suggests that the chrysanthemum plants (Ph-ch1 and Ph-ch2) be infected with a phytoplasma belonging to AY phytoplasma.

• Journal of Microbiology and Biotechnology
• /
• 제21권1호
• /
• pp.81-88
• /
• 2011

The anti-phytoplasma activities of surfactin (derived from Iranian native Bacillus subtilis isolates) and tetracycline towards Candidatus "Phytoplasma aurantifolia", the agent of lime Witches' broom disease, were investigated. HPLC was used to quantify the surfactin production in four previously characterized native surfactin-producing strains, and the one producing the highest amount of surfactin (about 1,500 mg/l) was selected and cultivated following optimized production and extraction protocols. Different combinations of purified surfactin and commercial tetracycline were injected into artificially phytoplasmainfected Mexican lime seedlings using a syringe injection system. An absolute quantitative real-time PCR system was developed to monitor the phytoplasma population shifts in the lime phloem during 3 months following the injections. The results revealed that the injections of surfactin or tetracycline had a significant inhibitory effect on Candidatus "P. aurantifolia". However, the combined treatment with both surfactin and tetracycline (1:1) resulted in the highest inhibition due to a synergic effect, which suppressed the phytoplasma population from about $2{\times}10^5$ to less than 10 phytoplasma units/g plant tissue.

• The Plant Pathology Journal
• /
• 제36권5호
• /
• pp.459-467
• /
• 2020

Areca palm yellow leaf (AYL) disease caused by the 16SrI group phytoplasma is a serious threat to the development of the Areca palm industry in China. The 16S rRNA gene sequence was utilized to establish a rapid and efficient detection system efficient for the 16SrI-B subgroup AYL phytoplasma in China by loop-mediated isothermal amplification (LAMP). The results showed that two sets of LAMP detection primers, 16SrDNA-2 and 16SrDNA-3, were efficient for 16SrI-B subgroup AYL phytoplasma in China, with positive results appearing under reaction conditions of 64℃ for 40 min. The lowest detection limit for the two LAMP detection assays was the same at 200 ag/μl, namely approximately 53 copies/μl of the target fragments. Phytoplasma was detected in all AYL disease samples from Baoting, Tunchang, and Wanning counties in Hainan province using the two sets of LAMP primers 16SrDNA-2 and 16SrDNA-3, whereas no phytoplasma was detected in the negative control. The LAMP method established in this study with comparatively high sensitivity and stability, provides reliable results that could be visually detected, making it suitable for application and research in rapid diagnosis of AYL disease, detection of seedlings with the pathogen and breeding of disease-resistant Areca palm varieties.

• 한국식물병리학회지
• /
• 제13권4호
• /
• pp.239-243
• /
• 1997

1990년 8월 충북 보은의 참깨 밭에서 전형적인 엽화병(葉化病; phyllody disease)이 발생하였다. 병징은 꽃이 잎처럼 녹색으로 변하고, 이병엽은 정상엽보다 작고 잔가지가 마치 빗자루 모양으로 총생하였고 개화 및 결실이 되지 않았다. 투과 전자현미경으로 병든 잎의 사관요소에서 phytoplasma가 존재하는 것을 확인하였다. 병든 잔가지에서 추출한 DNA를 중합효소 연쇄반응으로 분석한 결과 대추나무 빗자루병에 걸린 나무에서 증폭되는 DNA와 같은 크기의 band가 관찰되었다. 따라서 위의 시료는 phytoplasma 벙으로 확인 되었으며 참깨 엽화병으로 명명하였다. 또한 참깨 엽화병을 일으키는 phytoplasma와 대추 나무 빗자루병 phytoplasma를 PCR 증폭 및 제한효소로 절단하여 분석한 결과 이들은 서로 다른 그룹이라는 것을 알 수 있었다.

• The Plant Pathology Journal
• /
• 제27권4호
• /
• pp.367-371
• /
• 2011

Multiplex PCR assays were developed for the simultaneous detection of ten important Korean quarantine phytoplasmas. The species-specific primers were designed based on ribosomal protein, putative preprotein translocase Y, immunodominant protein, elongation factor TU, chaperonin protein and the 16S rRNA genes of 'Candidatus (Ca.) Phytoplasma' species. Three main primer sets were prepared from ten designed primer pairs to limit nonspecific amplification as much as possible. The multiplex PCR assay using the three primer sets successfully amplified the correct conserved genes for each 'Ca. Phytoplasma' species. In addition, ten important 'Ca. Phytoplasma' species could be easily determined by recognizing band patterns specific for each phytoplasma species from three primer sets. Moreover, a high sensitivity of multiplex PCR for each primer set was observed for samples containing a low DNA concentration (10 ng/${\mu}l$). This study provides the useful multiplex PCR assay as a convenient method to detect the presence of ten important quarantine phytoplasmas in Korea.

• 식물병연구
• /
• 제7권2호
• /
• pp.116-119
• /
• 2001

Witches' broom symptoms were firstly found on tubers of Solanum tuberosum cv, Deijima, showing dense growth of spindly sprouts in Cheju province, Korea. Plantlets from the diseased plants also produced the typical witches' broom symptoms, having densely-growing small leaves when they became adult plants. At the later stages the diseased leaves were blightened. Presence of phytoplasma in plant tissues was confirmed by DAPI-staining fluorescence microscopy and electron microscopy, exhibiting its localization in sieve tubes of stem, petiole, and midrib. This is the first report of potato witches' broom in Korea.