scholarly journals Deteksi Molekuler Burkholderia glumae, Penyebab Penyakit Hawar Malai Padi

2018 ◽  
Vol 22 (1) ◽  
pp. 98
Author(s):  
Methy Handiyanti ◽  
Siti Subandiyah ◽  
Tri Joko
Keyword(s):  
Morphological Characteristics ◽  
Its Region ◽  
Selective Medium ◽  
Rice Seed ◽  
Disease Area ◽  
Burkholderia Glumae ◽  
Rice Varieties ◽  
Blight Disease ◽  
Spreading Potential ◽  
Panicle Blight

The presence of bacterial panicle blight disease caused by Burkholderia glumae have been reported to infect rice plants in Indonesia. There have been no reports of yield losses due to B. glumae infection, but this pathogen is seed-borne so that it can increase the spreading potential to other areas. This study aims to determine the spread of the disease area of bacterial panicle blight in Java and to detect B. glumae based on ITS region of 16-23S rDNA. Methods for this research include surveys and random sampling of rice seeds directly from farmers and the Food Crop and Horticulture Center, Agriculture Office of Yogyakarta. The bacteria were isolated using S-PG selective medium, then DNA extraction was performed and amplified using a pair of primers BGF 5’-ACACGGAACACCTGGGTA-3’ and BGR 5’-TCGCTCTCC CGAAGAGAT-3’. 101 isolates were obtained from 21 seed samples consisting of 11 rice varieties from nine regions in Java that has different morphological characteristics. The eight isolates were detected as B. glumae by using ITS primers, i.e., isolates ChgCM.4, IRP.3, IRP.6b, InSB.1a, InSB.2a, InSB.3a, InSB.5a, and InSB.6a. The eight isolates were isolated from seed samples of Cirebon, Purworejo and Banyuwangi. This study shows that bacterial panicle blight disease has found in several rice varieties and locations in Java, and the ITS primer can be used for early detection of B. glumae in rice seed samples. IntisariPenyakit hawar malai yang disebabkan oleh bakteri patogen Burkholderia glumae mulai banyak dilaporkan menginfeksi tanaman padi di Indonesia. Belum ada laporan mengenai kerugian akibat infeksi B. glumae di Indonesia, namun sifatnya yang tular benih dapat meningkatkan potensi menyebar ke wilayah lain. Penelitian ini bertujuan untuk mengetahui wilayah sebar penyakit hawar malai di Jawa dan mendeteksi secara molekuler berdasarkan urutan basa gen 16-23S rDNA internal transcribed spacer (ITS). Metode yang dilakukan meliputi survei dan pengambilan sampel biji padi secara acak langsung dari petani dan UPT Balai Pengembangan Perbenihan Tanaman Pangan dan Hortikultura, Dinas Pertanian Yogyakarta. Sampel biji padi diisolasi menggunakan media selektif S-PG, kemudian dilakukan ekstraksi DNA, dan diamplifikasi menggunakan primer BGF 5’-ACACGGAACACCTGGGTA-3’ dan BGR 5’-TCGCTCTCC CGAAGAGAT-3’. Hasil survei di lapangan diperoleh 21 sampel biji yang terdiri dari 11 varietas padi dari sembilan wilayah di Jawa. Hasil isolasi diperoleh 101 isolat dan masing-masing isolat tersebut memiliki karakteristik morfologi yang berbeda. Delapan isolat dari total isolat yang diuji terdeteksi B. glumae menggunakan primer ITS, yaitu isolat ChgCM.4, IRP.3, IRP.6b, InSB.1a, InSB.2a, InSB.3a, InSB.5a, dan InSB.6a. Kedelapan isolat tersebut merupakan hasil isolasi sampel biji dari wilayah Cirebon, Purworejo, dan Banyuwangi. Hasil penelitian menunjukkan bahwa penyakit hawar malai bakteri sudah terdeteksi pada varietas padi di beberapa lokasi wilayah Jawa, dan penggunaan primer ITS dapat digunakan untuk deteksi dini B. glumae pada sampel biji padi secara molekuler.

scholarly journals RESISTANCE OF SEVERAL RICE VARIETIES AGAINST THE BACTERIAL PANICLE BLIGHT DISEASE (Burkholderia glumae)

2019 ◽  
Vol 19 (1) ◽  
pp. 15
Author(s):  
Nurni Wahidah ◽  
Irda Safni ◽  
Hasanuddin Hasanuddin ◽  
Lisnawita Lisnawita
Keyword(s):  
Leaf Sheath ◽  
Positive Control ◽  
Negative Control ◽  
Control Factor ◽  
Burkholderia Glumae ◽  
Rice Varieties ◽  
Blight Disease ◽  
Number Of Seeds ◽  
Empty Seeds ◽  
Panicle Blight

Resistance of Several Rice Varieties against the Bacterial Panicle Blight Disease (Burkholderia glumae) .Burkholderia glumae is included as A2 Quarantine Plant Pest Organism, which is found in some restricted area in Indonesia.  B. glumae is a seedborne pathogen that causes panicle blight, seedling rot, grain rotand leaf sheath browning on rice plants. This research was objected  to determine the resistance of five  rice varieties against bacterial panicle blight pathogen. The experiment was carried out at the screen house of Faculty of Agriculture, Universitas Sumatera Utara, Medan from May to September 2018. This experiment was designed using Factorial Completely Randomized Design (CRD) with 2 factors; Factor 1: B1 (sterile water as negative control), B2 (B. glumae isolate CH BJ), B3 (B. glumae isolate IR 64), B4 (B. glumae isolate IC PRC), B5 (B. glumae isolate DSMZ 9512ᵀ as positive control). Factor 2: V1 (Cisokan variety), V2 (Inpari 4 variety), V3 (Situbagendit variety), V4 (Inpari 32 variety) and V5 (Cidenu variety). The results showed that all five rice varieties were highly susceptible to bacterial panicle blight pathogen. Inpari 32 variety had the highest number of seeds and weight of 100 seeds and had the lowest percentage of empty seeds.  IR 64 variety had the lowest number of seeds and the weight of 100 seeds and had the highest percentage of empty seeds.

scholarly journals First Report of Curvularia Leaf Blight on Curcuma wenyujin Caused by Curvularia clavata in China

Plant Disease ◽  
2013 ◽  
Vol 97 (1) ◽  
pp. 138-138 ◽  
Author(s):  
X. Y. Chen ◽  
J. D. Feng ◽  
Z. Su ◽  
C. Sui ◽  
X. Huang
Keyword(s):  
Morphological Characteristics ◽  
Its Region ◽  
Leaf Blight ◽  
Hainan Province ◽  
Continuous Cropping ◽  
Single Spore ◽  
Chinese Medicinal Herb ◽  
First Report ◽  
Causal Pathogen ◽  
Blight Disease

Curcuma wenyujin Y.H. Chen & C. Ling is a traditional Chinese medicinal herb in the Zingiberaceae family. Commonly known as Wen yujin, the root is widely used for alleviating pain and protecting the liver. A severe leaf blight disease was observed in three C. wenyujin farms in Hainan Province of China in October 2010. The obvious symptoms of leaf blight, yellow to brown irregular lesions (1 to 20 cm) on C. wenyujin, usually began at the tips of leaves and the main veins. This disease, especially severe from August to October, caused heavy damage and 100% of mature plants (10 months old) in farms were infected. The disease was most severe when continuous cropping was performed and showed slight improvement when rotation was adopted. Farmers usually sprayed carbendazim (50% WP) and thiophanate-methyl (70% WP) to control this disease, but these treatments were not effective. To isolate the causal pathogen, diseased plants were collected in October 2010 from a field of the Hainan Branch Institute of Medicinal Plant Development in Hainan Province. Lesion tissue was removed from the border between symptomatic and healthy tissue, surface sterilized in 75% ethanol for 1 min, washed in three changes of sterile distilled water, transferred to potato dextrose agar (PDA) plates, and incubated at 28°C for 7 days. Single spore cultures of five isolates were obtained and identified as Curvularia clavata based on morphological characteristics (1). Conidia measured 20 to 29 × 7.5 to 10.5 μm (n = 100), were curved, 3-septate, and the third cell from the base was larger and darker than the others. Mycelia of single spore cultures growing on PDA for 5 days were used for DNA extraction using a plant genomic DNA kit (TIANGEN, Beijing). The internal transcribed spacer (ITS) region of the rDNA was amplified using primers ITS1 and ITS4. The amplicons were 562 bp in length (GenBank Accession No. JQ730852) and had 99% nucleotide identity with the GenBank Accession No. JN021115 and AF071336 of C. clavata. Pathogenicity tests were conducted using fresh and healthy detached Curcuma wenyujin leaves. Mycelial discs (10 mm) removed from a 5-day-old colony on PDA were used for inoculation. Each isolate was inoculated on three distinct leaves (two distinct inoculations per leaf). Three additional leaves inoculated with sterile PDA discs were used as control. Inoculated leaves were covered with a polythene film to maintain high humidity. Leaves in trays were kept in a growth chamber at 28°C and observed for symptom appearance every day. Five days after inoculation, inoculated leaves developed blight symptoms similar to those observed on naturally infected leaves. No symptoms were observed on non-inoculated leaves. C. clavata was reisolated from the inoculated leaves, thus fulfilling Koch's postulates. C. clavata has been previously reported to be economically important on a number of other hosts (2). To our knowledge, this is the first report of Curvularia leaf blight on Curcuma wenyujin caused by C. clavata in China. References: (1) A. M Mandokhot et al. Eur. J. Plant Pathol.78:65, 1972. (2) T. Y. Zhang et al. Flora fungorum sinicorum: Beijing, China, 2010.

scholarly journals First report of fruit blight caused by Alternaria alternata on sesame in Northeast China

Plant Disease ◽  
2021 ◽  
Author(s):  
Hongsen Cheng ◽  
De Xue Gao ◽  
Huijie Sun ◽  
Yanbin Na ◽  
Jing Xu
Keyword(s):  
Alternaria Alternata ◽  
Morphological Characteristics ◽  
Its Region ◽  
Liaoning Province ◽  
Oilseed Crop ◽  
Distilled Water ◽  
Conidial Suspension ◽  
First Report ◽  
Health Products ◽  
Blight Disease

Sesame (Sesamum indicum L.) is an important oilseed crop in China and it is also used in food and health products. In August of 2019, a blight sesame fruit was observed in a field of Liaoyang city, Liaoning province of China. Initial disease symptoms consisted of brown or dark brown spots on fruit. With time, lesions coalesced and the whole fruit turned dark brown or black. Most of the diseased fruit had thin and small, deformed, necrotic, hardened cracked epidermal lesions. Lesions were also produced on stem and petioles leading to leaf abscission. The disease results in premature fruit death, and in turn, considerable yield losses. To determine the causal agent, symptomatic fruit with developing lesions were collected, and surface sterilized in 2% NaClO for 3 min, rinsed three times in distilled water, and plated onto PDA medium. After incubation at 25°C for 5 days, a dark olivaceous fungus with abundant, branched, brown to black, and septate hyphae was consistently isolated. Twenty single spores were separated with an inoculation needle under stereomicroscope. The conidia were in chains, brown, obclavate, ovoid or ellipsoid, with 1-6 transverse septa and 0-4 longitudinal or oblique septa 12.5 to 45 × 6.5 to 14.5 μm in size. Conidiophores were septate, light brown to olive brown, measuring 22-60 μm × 2-4 μm. The morphological characteristics of the 20 isolates all matched the description of Alternaria alternata (Simmons, 2007). The internal transcribed spacer (ITS) region of rDNA of 15 isolates was amplified using primers ITS1/ITS4 (White et al. 1990) and EF1-728F/EF1-986R (Carbone et al. 1999) and sequenced. Identical sequences were obtained and the sequence of the isolate ZMHG12 was submitted to GenBank (Accession no. MW418181 and MW700316). BLAST analysis of the sequences of the isolates of ZMHG12 showed 100% to A. alternata (KP739875 and LC132712). In pathogenicity tests, a conidial suspension (2.5 × 105 conidia per ml) was prepared from 7 days-old cultures of isolate ZMHG12 grown on PDA at 25°C. Fruit of 10 two-month-old potted sesame plants (Variety “Liaozhi 8”) were sprayed with the conidia suspension until runoff. Another 10 plants sprayed with distilled water to served as non-inoculated controls. All plants were maintained for 48 h in a humid chamber with a temperature of 25°C to 26°C, and then moved to a greenhouse. Ten days after inoculation, all fruit of inoculated plants exhibited symptoms similar to those observed in the field and non-inoculated control plants remained symptomless. The experiment was repeated twice with similar results. A. alternata has been reported as a pathogen caused leaf blight disease of sesame in Pakistan (Nayyar et al. 2017). To our knowledge, this is the first report of A.alternata causing fruit blight of sesame in China. To date, we have observed the disease on sesames in fields of Fuxin, Chaoyang and Tieling city in Liaoning Province, and Tongliao city in Inner Mongolia of China, and it has become an important disease in sesame production of China. References : Simmons E. G. 2007. Alternaria: An identification manual. CBS Fungal Biodiversity Center, Utrecht, Netherlands. White T. J., et al. 1990. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego. Carbone I., et al. 1999. Mycologia, 91: 553-556. Nayyar, B. G., et al. 2017. Plant Pathology Journal, 33 (6): 543-553.

scholarly journals Prevalence of Burkholderia glumae in rice crops in Ecuador

2018 ◽  
Vol 102 (1-2) ◽  
pp. 65-78
Author(s):  
Lenin Celiano Paz-Carrasco ◽  
Luz Diana Intriago-Mendoza ◽  
Marcos Fernando Basso ◽  
Roberto E. Celi-Herán
Keyword(s):  
Economic Importance ◽  
23S Rrna ◽  
Bacterial Isolates ◽  
Severe Damage ◽  
Burkholderia Glumae ◽  
Genetic Studies ◽  
Molecular Assays ◽  
Blight Disease ◽  
Panicle Blight

Burkholderia glumae is the agent responsible for bacterial panicle blight disease (BPBD) of rice that causes severe damage to this crop worldwide. During 2012 and 2013, symptoms of BPBD were observed in Palestina city, located in Guayas province, Ecuador. In 2014, the presence of B. glumae was confirmed at this location. In view of the socio-economic importance of rice in Ecuador, this research aimed to investigate the prevalence of B. glumae in other rice-producing regions. Eighteen bacterial isolates obtained from blighted kernels were characterized. Physiological, biochemical, serological, and molecular assays and the amplification of the 16S-23S rRNA ITS of the bacterial isolates collected confirmed the identity of the BPBD-associated bacterium. Pathogenicity assays verified the ability of these isolates to produce discoloration, spotting, and empty grains, symptoms associated with BPBD. Antibiotic assays showed that EC-EELS-01 isolate was sensitive to ciprofloxacin and tetracycline, and resistant to polymyxin. The dissemination and prevalence of B. glumae were confirmed in the rice-producing areas of El Oro, Cañar, Guayas, and Los Rios provinces. This research will serve to develop genetic studies to characterize the population in the B. glumae isolates in Ecuador.

scholarly journals An Overview of Rice QTLs Associated with Disease Resistance to Three Major Rice Diseases: Blast, Sheath Blight, and Bacterial Panicle Blight

Agronomy ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 177 ◽  
Author(s):  
Seyedeh Soheila Zarbafi ◽  
Jong Hyun Ham
Keyword(s):  
Disease Resistance ◽  
Oryza Sativa L ◽  
Quantitative Resistance ◽  
Sheath Blight ◽  
Yield Potential ◽  
Burkholderia Glumae ◽  
Rice Varieties ◽  
Disease Resistant ◽  
Resistant Varieties ◽  
Panicle Blight

Rice (Oryza sativa L.) is one of the most important crops that are produced as human food, directly feeding people more than any other crop. Hence, it is important to increase the yield potential of rice through improving the disease resistance to prevailing rice diseases. Blast caused by the fungus Magnaporthe oryzae, sheath blight caused by the fungus Rhizoctonia solani Kühn, and bacterial panicle blight caused by the bacteria Burkholderia glumae and B. gladioli are serious rice diseases in many rice-producing regions. In spite of the chronic damages from these major diseases, the quantitative resistance to each of them is not known very well and any available disease-resistant varieties are rare or not stable. Although gene-for-gene resistance that is mediated by an R-Avr interaction has been intensively studied for blast, quantitative (or horizontal) resistance to a broad spectrum of races in M. oryzae is still poorly understood. Identification of the quantitative trait loci (QTLs) related to these diseases and using marker technology can facilitate marker-assisted selection to screen resistant traits in individual resources, which could ultimately lead to the development of novel disease-resistant rice varieties. This article is a summary of identified QTLs that are associated with rice diseases, including blast, sheath blight, and bacterial panicle blight that can be used in breeding programs.

scholarly journals First Report of Taro (Colocasia esculenta) Leaf Blight Caused by Phytophthora colocasiae in Nigeria

Plant Disease ◽  
2011 ◽  
Vol 95 (5) ◽  
pp. 618-618 ◽  
Author(s):  
R. Bandyopadhyay ◽  
K. Sharma ◽  
T. J. Onyeka ◽  
A. Aregbesola ◽  
P. Lava Kumar
Keyword(s):  
Crop Protection ◽  
Central Africa ◽  
Morphological Characteristics ◽  
Its Region ◽  
Selective Medium ◽  
Colocasia Esculenta ◽  
Leaf Blight ◽  
Pathogenicity Test ◽  
Phytophthora Colocasiae ◽  
Detached Leaves

In November 2009, many farmers in Abia State were alarmed by complete destruction of their taro (Colocasia esculenta (L.) Schott.) crop. Symptoms, suggestive of leaf blight caused by Phytophthora colocasiae Raciborski (2), began as small, brown, water-soaked lesions that rapidly enlarged to form large, dark brown, coalescing lesions, sometimes with orange host exudations. White sporulation was evident on the lesion surface under wet conditions. The pathogen caused rapid defoliation and killed plants. The epidemic was widespread in 2010 during the rainy season (April to November) in all taro-growing areas of Nigeria. Diseased leaves were collected from taro in Iwo Village near Ibadan, cut into 4-cm2 pieces, washed in several changes of sterile water, and incubated in petri dishes lined with wet filter paper at 22°C. Newly produced sporangia were collected from the incubated leaves and plated on a selective medium (1). Sporangia were hyaline, papillate, and measured 25 to 55 × 15 to 30 μm. Zoospores encysted within 30 min after release; cysts were 9.7 to 19.5 μm in diameter. Sporangia and zoospore formation were induced in water and by chilling, respectively (1). Two leaves each of three 1-month-old taro and three Xanthosoma plants (both unknown clones) and six detached leaves of taro were inoculated with a 1 × 105/ml zoospore suspension of isolates PC01 and PC02. Detached leaves were incubated in moist chambers at 22°C. Plants were covered with polyethylene bags for 12 h after inoculation and maintained in a screenhouse. Water-soaked lesions appeared on detached leaves within 24 h postinoculation and the leaves were completely rotted 48 h later. All inoculated attached leaves of taro, but not Xanthosoma, showed typical leaf blight symptoms including abundant sporangial production. Noninoculated control detached leaves and plants were disease free. Sporangia from detached and attached inoculated leaves, when plated on selective medium, produced typical P. colocasiae colonies. The internal transcribed spacer (ITS) region of rDNA was amplified using the ITS1 and ITS4 primers (3). Amplicons (786 bp) were sequenced in both directions and submitted to GenBank (Accession Nos. HQ602756, HQ602757, HQ602758, and HQ602759). A BLASTn search revealed 99% similarity to a P. colocasiae strain of the Pacific Region (Accession No. GU111604), but only 94% similarity to a P. colocasiae strain from India (Accession No. GQ202149). The sequence analysis, morphological characteristics, and pathogenicity test confirmed the taro leaf blight pathogen as P. colocasiae. There are previous reports of occurrence of taro blight-like disease attributed to P. colocasiae in Ethiopia, Equatorial Guinea (1), and more recently in Cameroon, but comprehensive details on pathogen or disease are not available. To our knowledge, this is the first confirmed record in Nigeria of P. colocasiae causing taro blight. This disease poses a serious threat to the production and biodiversity of this important food crop. Urgent interventions are necessary to halt this emerging epidemic in West and Central Africa. References: (1) Phytophthora colocasiae, In: CABI-Crop Protection Compendium. CAB International, Wallingford, UK, 2005. (2) P. S. Tsao. Page 219 in: Phytophthora: Its Biology, Taxonomy, Ecology and Pathology. The American Phytopathological Society. St. Paul, MN, 1983. (3) T. J. White et al. Page 315 in: PCR Protocol: A Guide to Methods and Applications. Academic Press, London. 1990.

scholarly journals First Report of Neofusicoccum parvum Causing Panicle Blight and Leaf Spot on Vitis heyneana in China

Plant Disease ◽  
2015 ◽  
Vol 99 (3) ◽  
pp. 417-417 ◽  
Author(s):  
D. D. Wu ◽  
G. Fu ◽  
Y. F. Ye ◽  
F. Y. Hu ◽  
H. F. Mou ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Severe Disease ◽  
Morphological Characteristics ◽  
Aerial Mycelium ◽  
Its Region ◽  
Average Diameter ◽  
Wine Production ◽  
Neofusicoccum Parvum ◽  
First Report ◽  
Panicle Blight

The climbing vine, Vitis heyneana Roem. & Schult, is a member of the grape family endemic to Asia. Its fruits are used in wine production, and its roots, stems, and leaves can be used in medicinal materials. This plant is grown in Southwest China, as well as in India, Bhutan, and Nepal. Mulao Autonomous County in Guangxi Province is the only artificial cultivation area in China. During the summer of 2013, a panicle blight and leaf spot were detected on V. heyneana on four farms in Mulao Autonomous County. The symptoms were observed from the onset of florescence through fruit harvest. Brown lesions initially appeared at the base of a panicle and then extended to the whole panicle, finally causing the panicle to die and fruit to drop. When the disease developed on leaves, the symptom initially appeared as small dark brown circular spots, later enlarging into irregular spots (average diameter 6 mm) with a light brown center and dark brown rim. With severe disease, some individual leaves were affected by numerous spots, leading to premature senescence. Small sections of diseased tissue excised from 10 panicle and 10 leaf samples were plated on potato dextrose agar (PDA) and incubated at 28°C. Fungal colonies developed, initially with abundant white aerial mycelium, which turned olivaceous gray after 5 days and formed black pycnidia after 25 days. The conidia were hyaline, ellipsoidal to fusiform, externally smooth, thin-walled, and nonseptate. Thirty conidia were measured; the dimensions were 12.0 to 17.5 × 4.0 to 6.0 μm. Morphological characteristics of the isolates were similar to the descriptions of Neofusicoccum parvum (3). The isolate MPT-1 was selected as a representative for molecular identification. Genomic DNA was extracted and used for PCR to amplify the internal transcribed spacer (ITS) region and partial translation elongation factor 1-alpha (EF1-α) gene, using primers ITS1/ITS4 and EF1-728F/EF1-986R, respectively. The obtained ITS sequence (GenBank Accession No. KJ599627) and EF1-α sequence (KM921768) showed >99% homology with several GenBank sequences of N. parvum. Morphological and molecular results confirmed the isolate as N. parvum. For pathogenicity tests, detached, young healthy panicles and leaves of V. heyneana were surface-sterilized, wounded by sterile needle, and inoculated with mycelial plugs (3 mm in diameter) of four N. parvum isolates. Ten panicles and 10 leaves were used for every isolate. Control panicles and leaves were treated with sterile PDA plugs. All the samples were placed in a humid chamber (RH 90%, 28°C, 12 h of light) for 3 days. Symptoms similar to those observed in the field developed on all panicles and leaves inoculated with N. parvum isolates. N. parvum was reisolated from all inoculated, symptomatic tissues. The controls remained symptomless. N. parvum has been reported to cause trunk canker on V. vinifera (2), dieback on Cupressus funebris (3), and a leaf spot on Myristica fragrans (1). To our knowledge, this is the first report of N. parvum causing panicle blight and leaf spot on V. heyneana in China. Panicle blight caused a large number of fruits to drop and reduced the yield seriously. Some effective measures should be taken to control this disease. References: (1) V. Jayakumar et al. New Dis. Rep. 23:19, 2011. (2) J. Kaliternam et al. Plant Dis. 97:1656, 2013. (3) S. B. Li et al. Plant Dis. 94:641, 2010.

scholarly journals First Report of Burkholderia glumae Causing Bacterial Panicle Blight on Rice in Ecuador

Plant Disease ◽  
2014 ◽  
Vol 98 (7) ◽  
pp. 988-988 ◽  
Author(s):  
C. Riera-Ruiz ◽  
J. Vargas ◽  
C. Cedeño ◽  
P. Quirola ◽  
M. Escobar ◽  
...  
Keyword(s):  
Uv Light ◽  
Oryza Sativa L ◽  
Bacterial Species ◽  
Methyl Violet ◽  
Selective Medium ◽  
Phenol Red ◽  
Biochemical Tests ◽  
Burkholderia Glumae ◽  
First Report ◽  
Panicle Blight

Rice (Oryza sativa L.) is one of the leading crops and the basis of most diets in Ecuador and other countries. Diseases such as bacterial panicle blight (BPB), also known as seedling rot or grain rot, have the potential to threaten rice production worldwide. Burkholderia glumae, a causal agent of BPB, has severely affected the rice industry in many countries of Africa, Asia, and the Americas (1,2,4), but no report of this bacteria in Ecuador can be found in the literature. Rice plantations showing BPB-like symptoms including upright panicles with stained and vain grains were spotted in Palestina city, one of Ecuador's most extensive rice areas, in July 2013, but similar symptoms have been observed in the region since early 2012. Six symptomatic plants from two different groves were collected. Samples were plated on the semi-selective medium S-PG (KH2PO4 1.3 g, Na2HPO4 1.2 g, (NH4)2SO4 5 g, MgSO4·7H2O 0.25 g, Na2MoO4·2H2O 24 mg, EDTA-Fe 10 mg, L-cystine 10 μg, D-sorbitol 10 g, pheneticillin potassium 50 mg, ampicillin sodium 10 mg, cetrimide 10 mg, methyl violet 1 mg, phenol red 20 mg, agar 15 g/liter distilled water) and axenic colonies were transferred to potato dextrose agar (PDA) to test for fluorescence (3). Colonies of the potential pathogen were 1 mm, circular, entire margin, with a smooth and shiny surface. When cultured in PDA, isolates showed a moist texture, dull yellow color, and displayed fluorescence with exposure to UV light. Cells were bacterial gram-negative rods of 1 to 2 × 0.5 μm. Twelve presumptive isolates were submitted to biochemical tests (API 20NE). The biochemical profile (APIWEB) showed that all the isolates belonged to the Burkholderia genus with a 99.9% similarity. To determine the bacterial species, colonies were submitted to ELISA tests using specific antibodies for B. glumae from Agdia, Inc. The two isolates that were positive for B. glumae were sequenced using a part of the 16s rDNA amplified by the primers 536F: 5′-GTGCCAGCMGCCGCGGTAATAC-3′ and 1492R: 5′-GGTTACCTTGTTACGACTT-3′. The obtained sequences (deposited into GenBank as KF601202) shared 100% similarity with several B. glumae strains after a BLAST query. Isolates were then diluted to 108 UFC/ml and used to inoculate healthy rice plants. Inoculated plants produced BPB-like symptoms including upright panicles with stained vain grains and the bacterium was re-isolated from symptomatic plants. To the best of our knowledge, this is the first report of B. glumae in Ecuador. Further research is ongoing to identify and determine the pathogenicity of the remaining Burkholderia strains that tested negative for B. glumae. References: (1) J. Luo et al. Plant Dis. 91:1363, 2007. (2) R. Nandakumar et al. Plant Dis. 93:896, 2009. (3) T. Urakami et al. Int. J. Syst. Bacteriol. 44:235, 1994. (4) X.-G. Zhou. Plant Dis. 98:566, 2014.

scholarly journals Burkholderia glumae and B. gladioli Cause Bacterial Panicle Blight in Rice in the Southern United States

Plant Disease ◽  
2009 ◽  
Vol 93 (9) ◽  
pp. 896-905 ◽  
Author(s):  
Rangaraj Nandakumar ◽  
A. K. M. Shahjahan ◽  
X. L. Yuan ◽  
E. R. Dickstein ◽  
D. E. Groth ◽  
...  
Keyword(s):  
United States ◽  
Its Region ◽  
Accurate Method ◽  
Cellular Fatty Acid ◽  
Fatty Acid Analysis ◽  
Southern United States ◽  
Growth Responses ◽  
Bacterial Strains ◽  
Burkholderia Glumae ◽  
Panicle Blight

Bacterial panicle blight (BPB) is among the three most limiting rice diseases in Louisiana and the southern United States. The identity and characterization of pathogens associated with this disease was unclear. This research details studies carried out on the pathogens causing BPB on rice in Louisiana and other rice producing southern states. Bacterial strains were isolated from BPB-infected sheath, panicle, or grain samples collected from rice fields in Louisiana, Arkansas, Texas, and Mississippi. In greenhouse inoculation tests, 292 of 364 strains were pathogenic on rice seedlings or panicles. Identification of strains in the pathogen complex by growth on S-PG medium, carbon source utilization profile (Biolog), cellular fatty acid analysis, and polymerase chain reaction (PCR) methods revealed that 76 and 5% of the strains were Burkholderia glumae and B. gladioli, respectively. The other strains have not been conclusively identified. Although strains of both species produced similar symptoms on rice, B. glumae strains were generally more aggressive and caused more severe symptoms on rice than B. gladioli. Virulent strains of both species produced toxoflavin in culture. The two species had similar growth responses to temperature, and optima ranged from 38 to 40°C for B. glumae and 35 to 37°C for B. gladioli. PCR was the most sensitive and accurate method tested for identifying the bacterial pathogens to the species level. The 16S rDNA gene and 16S-23S rDNA internal transcribed spacer (ITS) region sequences of the B. glumae and B. gladioli strains from rice showed more than 99% sequence homology with published sequences. A real-time PCR system was developed to detect and quantify this pathogen from infected seed lots. Our results clearly indicate that B. glumae and B. gladioli were the major pathogens causing BPB in the southern United States.

Sign in / Sign up

Export Citation Format

Share Document