scholarly journals First Report of Sarocladium oryzae Causing Sheath Rot on Rice (Oryza sativa) in Western Australia

Plant Disease ◽  
2012 ◽  
Vol 96 (9) ◽  
pp. 1382-1382 ◽  
Author(s):  
V. Lanoiselet ◽  
M. P. You ◽  
Y. P. Li ◽  
C. P. Wang ◽  
R. G. Shivas ◽  
...  
Keyword(s):  
Oryza Sativa ◽  
Western Australia ◽  
Oryza Sativa L ◽  
Culture Collection ◽  
Universal Primers ◽  
Rrna Gene ◽  
Sequence Information ◽  
Post Inoculation ◽  
First Report ◽  
Sheath Rot

Rice (Oryza sativa L.) has been grown in the Ord River Irrigation Area (ORIA) in northern Western Australia since 1960. In 2011, a sheath rot of rice was observed in the ORIA. Symptoms were variable, appearing as either (i) oblong pale to dark brown lesions up to 3 cm length, (ii) lesions with pale grey/brown centers and with dark brown margins, or (iii) diffuse dark or reddish brown streaks along the sheath. Lesions enlarged and coalesced, often covering the majority of the leaf sheath, disrupting panicle emergence. Isolations from small pieces of infested tissues from plants showing sheath rot symptoms were made onto water agar, subcultured onto potato dextrose agar, cultures maintained at 20°C, and a representative culture lodged both in the Western Australian Culture Collection maintained at the Department of Agriculture and Food Western Australia (as WAC 13481) and in the culture collection located at the DAFF Plant Pathology Herbarium (as BRIP 54763). Amplification of the internal transcribed spacer (ITS)1 and (ITS)2 regions flanking the 5.8S rRNA gene were carried out with universal primers ITS1 and ITS4 according to the published protocol (4). The DNA PCR products from a single isolate were sequenced and BLAST analyses used to compare sequences with those in GenBank. The sequence had 99% nucleotide identity with the corresponding sequence in GenBank for Sarocladium oryzae (Sawada) W. Gams & D. Hawksworth. Isolates showed morphological (e.g., conidiophore and conidia characteristics) (2) and molecular (1) similarities with S. oryzae as described in other reports. The relevant sequence information for a representative isolate was lodged in GenBank (GenBank Accession No. JQ965668). Spores of S. oryzae were produced on rice agar under “black light” at 22°C to induce sporulation over 4 weeks. Under conditions of 30/28°C (day/night), 14/12 h (light/dark), rice cv. Quest, grown for 11 weeks until plants reached the tillering stage, was inoculated by spraying a suspension 5 × 107 spores/ml of the same single isolate onto foliage until runoff occurred. Inoculated plants were placed under a dark plastic cover for 72 h to maximize humidity levels around leaves and subsequently maintained under >90% relative humidity conditions. Symptoms of sheath rot as described in (i) and (ii) above appeared by 14 days after inoculation, with lesions up to 23 cm long by 15 days post-inoculation. Severe disease prevented young panicles from emerging. Infection studies were successfully repeated and S. oryzae was reisolated from leaf lesions 1 week after lesion appearance. No disease was observed on water-inoculated control rice plants. There have been records of S. oryzae on rice in New South Wales in the early 1980s (3) and in 2006 to 2007 (Australian Plant Pest Database), but to our knowledge, this is the first report of this pathogen in Western Australia. References: (1) N. Ayyadurai et al. Cur. Microbiol. Mycologia 50:319, 2005. (2) B. L. K. Brady. No. 673 in: IMI Descriptions of Fungi and Bacteria, 1980. (3) D. Phillips et al. FAO Plant Prot. Bull. 40:4, 1992. (4) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990.

scholarly journals First Report of Rice Blast (Magnaporthe oryzae) on Rice (Oryza sativa) in Western Australia

Plant Disease ◽  
2012 ◽  
Vol 96 (8) ◽  
pp. 1228-1228 ◽  
Author(s):  
M. P. You ◽  
V. Lanoiselet ◽  
C. P. Wang ◽  
R. G. Shivas ◽  
Y. P. Li ◽  
...  
Keyword(s):  
Oryza Sativa ◽  
Western Australia ◽  
Magnaporthe Oryzae ◽  
Leaf Spot ◽  
Rice Blast ◽  
Universal Primers ◽  
Rrna Gene ◽  
Sequence Information ◽  
First Report ◽  
Β Tubulin

Commercial rice crops (Oryza sativa L.) have been recently reintroduced to the Ord River Irrigation Area in northern Western Australia. In early August 2011, unusual leaf spot symptoms were observed by a local rice grower on rice cultivar Quest. A leaf spot symptom initially appeared as grey-green and/or water soaked with a darker green border and then expanded rapidly to several centimeters in length and became light tan in color with a distinct necrotic border. Isolations from typical leaf lesions were made onto water agar, subcultured onto potato dextrose agar, and maintained at 20°C. A representative culture was lodged in the Western Australian Culture Collection Herbarium, Department of Agriculture and Food Western Australia (WAC 13466) and as a herbarium specimen in the Plant Pathology Herbarium, Plant Biosecurity Science (BRIP 54721). Amplification of the internal transcribed spacer (ITS)1 and (ITS)2 regions flanking the 5.8S rRNA gene were carried out with universal primers ITS1 and ITS4 (4). The PCR products were sequenced and BLAST analyses used to compare sequences with those in GenBank. The sequence had 99% nucleotide identity with the corresponding sequence in GenBank for Magnaporthe oryzae B.C. Couch, the causal agent of rice blast, the most important fungal disease of rice worldwide (1). Additional sequencing with the primers Bt1a/Bt1b for the β-tubulin gene, primers ACT-512F/ACT-783R for the actin gene, and primers CAL-228F/CAL-737R for the calmodulin gene showed 100% identity in each case with M. oryzae sequences in GenBank, confirming molecular similarity with other reports, e.g., (1). The relevant sequence information for a representative isolate has been lodged in GenBank (GenBank Accession Nos. JQ911754 for (ITS) 1 and 2; JX014265 for β-tubulin; JX035809 for actin; and JX035808 for calmodulin). Isolates also showed morphological similarity with M. oryzae as described in other reports, e.g., (3). Spores of M. oryzae were produced on rice agar under “black light” at 21°C for 4 weeks. Under 30/28°C (day/night), 14/12 h (light/dark), rice cv. Quest was grown for 7 weeks, and inoculated by spraying a suspension 5 × 105 spores/ml onto foliage until runoff occurred. Inoculated plants were placed under a dark plastic covering for 72 h to maximize humidity levels around leaves, and subsequently maintained under >90% RH conditions. Typical symptoms of rice blast appeared within 14 days of inoculation and were as described above. Infection studies were successfully repeated and M. oryzae was readily reisolated from leaf lesions. No disease symptoms were observed nor was M. oryzae isolated from water-inoculated control rice plants. There have been previous records of rice blast in the Northern Territory (2) and Queensland, Australia (Australian Plant Pest Database), but this is the first report of M. oryzae in Western Australia, where it could potentially be destructive if conditions prove conducive. References: (1) B. C. Couch and L. M. Kohn. Mycologia 94:683, 2002; (2) J. B. Heaton. The Aust. J. Sci. 27:81, 1964; (3) C. V. Subramanian. IMI Descriptions of Fungi and Bacteria No 169, Pyricularia oryzae, 1968; (4) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, New York, 1990.

scholarly journals First Report of Phoma herbarum on Tedera (Bituminaria bituminosa var. albomarginata) in Australia

Plant Disease ◽  
2012 ◽  
Vol 96 (5) ◽  
pp. 769-769 ◽  
Author(s):  
Y. P. Li ◽  
D. G. Wright ◽  
V. Lanoiselet ◽  
C. P. Wang ◽  
N. Eyres ◽  
...  
Keyword(s):  
Western Australia ◽  
Culture Collection ◽  
Universal Primers ◽  
Rrna Gene ◽  
Sequence Information ◽  
Conidial Suspension ◽  
Single Spore ◽  
Published Report ◽  
Bituminaria Bituminosa ◽  
Phoma Herbarum

Tedera (Bituminaria bituminosa (L.) C.H. Stirton var. albomarginata) has been successfully established across the mixed-farming (wheat-sheep) region of Western Australia because this species has remarkable drought tolerance and can survive the dry-summer period with strong retention of green leaf. A leaf spot symptom involving pale brown lesions with distinct dark brown margins had been observed in genetic evaluation plots of tedera at Medina and Mount Barker, Western Australia, and a Phoma sp. was isolated. Single-spore isolations of a typical Phoma sp. isolate were made onto potato dextrose agar and maintained at 20°C, and a representative culture has been lodged in the Western Australian Culture Collection Herbarium maintained at the Department of Agriculture and Food Western Australia (Accession No. WAC13435). Amplification of the internal transcribed spacer (ITS) 1 and ITS2 regions flanking the 5.8S rRNA gene were carried out with universal primers ITS1 and ITS4 according to published protocol (3). The DNA PCR products were sequenced and BLAST analyses was used to compare sequences with those in GenBank. The sequence had 99% nucleotide identity with the corresponding sequence in GenBank for Phoma herbarum. Isolates also showed morphological (e.g., 1) and molecular (e.g., 2) similarities with P. herbarum as described in other reports. The relevant sequence information for a representative isolate has been lodged in GenBank (Accession No. JQ282910). A conidial suspension of 107 conidia ml–1 from a single-spore culture was spray inoculated onto foliage of 6-week-old tedera plants maintained under >90% relative humidity conditions for 72-h postinoculation. Symptoms evident by 10 days postinoculation consisted of pale brown lesions, mostly 1.5 to 4 mm in diameter, which developed a distinct, dark brown margin. Occasional lesions also showed a distinct chlorotic halo extending 1 to 1.5 mm outside the boundary of the lesion. Infection studies were successfully repeated twice and P. herbarum was readily reisolated from infected foliage. No disease was observed on and no P. herbarum were isolated from water-inoculated control plants. Except for a recent published report of P. herbarum on field pea (Pisum sativum L.) (2), this pathogen has only been noted in the Australian Plant Pest Database as occurring on lucerne (Medicago sativa L.) and soybean (Glycine max (L.) Merr.) in Western Australia in 1985 and on a Protea sp. in 1991. To our knowledge, this is the first published report of P. herbarum as a pathogen on tedera in Australia or elsewhere. That P. herbarum occurs on other hosts in Australia and has a wide host range elsewhere together suggest its potential to be a pathogen on a wider range of host genera and species. References: (1) G. L. Kinsey. No. 1501 in: IMI Descriptions of Fungi and Bacteria. 2002. (2) Y. P. Li et al. Plant Dis. 95:1590, 2011. (3) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990.

scholarly journals First Report of Bituminaria Witches'-Broom in Australia Caused by a 16SrII Phytoplasma

Plant Disease ◽  
2011 ◽  
Vol 95 (2) ◽  
pp. 226-226 ◽  
Author(s):  
N. Aryamanesh ◽  
A. M. Al-Subhi ◽  
R. Snowball ◽  
G. Yan ◽  
K. H. M. Siddique
Keyword(s):  
Canary Islands ◽  
Western Australia ◽  
Nested Pcr ◽  
Perfect Match ◽  
Universal Primers ◽  
Healthy Plant ◽  
Rrna Gene ◽  
Polymorphism Analysis ◽  
First Report ◽  
Two Samples

Bituminaria bituminosa (L.) Stirt. is a perennial legume known as Arabian pea that is used as a forage in arid areas and for stabilization of degraded soils. It is widely distributed in the Mediterranean Basin with wider adaptation across the Canary Islands (4). In July 2010, during a survey for phytoplasma, some Canary Island B. bituminosa plants with typical phytoplasma symptoms, including stunted growth with small leaves, shortened internodes, and bushy growth, were found in seed multiplication nurseries at Medina, Perth, Western Australia (115°48.5′E; 32°13.2′S). Two samples from plants with clear disease symptoms and two visibly healthy plants were collected and total DNA was extracted with the Illustra DNA extraction kit Phytopure (GE Healthcare) according to the manufacturer's instructions. Direct and nested PCR were used to test the presence of phytoplasma 16S rDNA in samples with universal primers P1/P7 and R16F2n/R16R2, respectively (1,3). The PCR amplifications from all diseased samples yielded an expected product of 1.8 kb by direct and 1.2 kb by nested PCR, but not from the healthy plant samples. The direct PCR product was used as a template DNA in sequencing and the DNA sequence was deposited in the NCBI GenBank (Accession No. HQ404357). Sequence homology analysis indicated there was a perfect match between the two isolates. BLAST search of the NCBI GenBank revealed that B. bituminosa phytoplasma shares >99% sequence identity with Crotalaria witches'-broom phytoplasma (Accession No. EU650181.1), pear decline phytoplasma (Accession No. EF656453.1), and Scaevola witches'-broom phytoplasma (Accession No. AB257291.1). On the basis of BLAST analyses of 16S rRNA gene sequences, B. bituminosa phytoplasma in Western Australia appears to belong to the peanut witches'-broom group (16SrII-D) of phytoplasma. Restriction fragment length polymorphism analysis was also performed on nested PCR products of two samples of B. bituminosa phytoplasma by separate digestion with HaeIII, Hind6I, HpaII, MboI, RsaI, Tru9I, and T-HB8I restriction enzymes. Samples yielded patterns similar to alfalfa witches'-broom phytoplasma (Accession No. AF438413) belonging to subgroup 16SrII-D (2). To our knowledge, this is the first report of a phytoplasma of the 16SrII-D group infecting B. bituminosa in Australia and should be referred to as “Bituminaria witches'-broom phytoplasma” (BiWB). This report also indicates that the occurrence of the phytoplasma in B. bituminosa may be widespread in the Canary Islands and other species of Bituminaria might be susceptible to infection by Bituminaria witches'-broom phytoplasma. References: (1) D. E. Gundersen and I.-M. Lee. Phytopathol. Mediterr. 35:144, 1996. (2) A. J. Khan et al. Phytopathology 92:1038, 2002. (3) I.-M. Lee et al. Int. J. Syst. Evol. Microbiol. 54:337, 2004. (4) P. Mendez et al. Grassland Sci. Eur. 11:300, 2006.

scholarly journals First Report of New Bacterial Leaf Blight of Rice Caused by Pantoea ananatis in Southeast China

Plant Disease ◽  
2021 ◽  
Author(s):  
Lin Yu ◽  
Changdeng Yang ◽  
Zhijuan Ji ◽  
Yuxiang Zeng ◽  
Yan Liang ◽  
...  
Keyword(s):  
Oryza Sativa L ◽  
Sequence Similarity ◽  
Disease Incidence ◽  
Leaf Blight ◽  
Bacterial Leaf Blight ◽  
Bacterial Suspension ◽  
Rrna Gene ◽  
Pantoea Ananatis ◽  
Southeast China ◽  
First Report

In autumn 2020, leaf blight was observed on rice (Oryza sativa L., variety Zhongzao39, Yongyou9, Yongyou12, Yongyou15, Yongyou18, Yongyou1540, Zhongzheyou8, Jiafengyou2, Xiangliangyou900 and Jiyou351) in the fields of 17 towns in Zhejiang and Jiangxi Provinces, China. The disease incidence was 45%-60%. Initially, water-soaked, linear, light brown lesions emerged in the upper blades of the leaves, and then spread down to leaf margins, which ultimately caused leaf curling and blight during the booting-harvest stage (Fig. S1). The disease symptoms were assumed to be caused by Xanthomonas oryzae pv. oryzae (Xoo), the pathogen of rice bacterial blight. 63 isolates were obtained from the collected diseased leaves as previously described (Hou et al. 2020). All isolates showed circular, smooth-margined, yellow colonies when cultured on peptone sugar agar (PSA) medium for 24h at 28℃. The cells were all gram-negative and rod-shaped with three to six peritrichous flagella; positive for catalase, indole, glucose fermentation and citrate utilization, while negative for oxidase, alkaline, phenylalanine deaminase, urease, and nitrate reductase reactions. 16S rRNA gene sequence analysis from the 6 isolates (FY43, JH31, JH99, TZ20, TZ39 and TZ68) revealed that the amplified fragments shared 98% similarity with Pantoea ananatis type strain LMG 2665T (GenBank JFZU01) (Table S3). To further verify P. ananatis identity of these isolates, fragments of three housekeeping genes including gyrB, leuS and rpoB from the 6 isolates were amplified and sequenced, which showed highest homology to LMG 2665T with a sequence similarity of 95%-100% (Table S3). Primers (Brady et al. 2008) and GenBank accession numbers of gene sequences from the 6 isolates are listed in Table S1 and Table S2. Phylogenetic analysis of gyrB, leuS and rpoB concatenated sequences indicated that the 6 isolates were clustered in a stable branch with P. ananatis (Fig. S2). Based on the above morphological, physiological, biochemical and molecular data, the isolates are identified as P. ananatis. For pathogenicity tests, bacterial suspension at 108 CFU/mL was inoculated into flag leaves of rice (cv. Zhongzao39) at the late booting stage using clipping method. Water was used as a negative control. The clipped leaves displayed water-soaked lesions at 3 to 5 days after inoculation (DAI); then the lesion spread downward and turned light brown. At about 14 DAI, blight was shown with similar symptoms to those samples collected from the rice field of Zhejiang and Jiangxi provinces (Fig. S1). In contrast, the control plants remained healthy and symptomless. The same P. ananatis was re-isolated in the inoculated rice plants, fulfilling Koch’s postulates. In the past decade, P. ananatis has been reported to cause grain discoloration in Hangzhou, China (Yan et al. 2010) and induce leaf blight as a companion of Enterobacter asburiae in Sichuan province, China (Xue et al. 2020). Nevertheless, to the best of our knowledge, this is the first report of P. ananatis as the causative agent of rice leaf blight in southeast China. This study raises the alarm that the emerging rice bacterial leaf blight in southeast China might be caused by a new pathogen P. ananatis, instead of Xoo as traditionally assumed. Further, the differences of occurrence, spread and control between two rice bacterial leaf blight diseases caused by P. ananatis and Xoo, respectively need to be determined in the future.

scholarly journals First Report of Strawberry Crown Rot Caused by Xanthomonas fragariae in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Zhiwei Song ◽  
Chen Yang ◽  
Rong Zeng ◽  
Shi-gang Gao ◽  
Wei Cheng ◽  
...  
Keyword(s):  
16S Rrna ◽  
Crown Rot ◽  
Universal Primers ◽  
Bacterial Suspension ◽  
Rrna Gene ◽  
Species Identity ◽  
Specific Primers ◽  
16S Rrna Sequence ◽  
First Report ◽  
Xanthomonas Fragariae

Strawberry (Fragaria × ananassa Duch.) is a kind of fruit with great economic importance and widely cultivated in the world. From 2019 to 2020, a serious crown rot disease was sporadically observed in several strawberry cultivars including ‘Zhang Ji’, ‘Hong Yan’ and ‘Yue Xiu’ in Shanghai, China. Initially, water-soaked rot appeared in inner tissue of strawberry crown, then progressed into browning and hollowing symptoms accompanied with yellow discolorations of young leaves. To isolate and identify the causal agent, small pieces of tissue taken from ten diseased crowns were sterilized by 70% alcohol. The cut-up pieces were macerated and serially diluted. The dilutions were placed on nutrient agar (NA) medium. After incubation at 25°C for 4-5 days, the yellow bacterial colonies were tiny and were streaked on NA plate for purification. The colonies were yellow, mucoid, smooth-margined, and five independent representative colonies were used for further confirmation. To confirm the species identity of the bacterial, genomic DNA was extracted from the five representative isolates, and 16S rRNA gene was amplified and sequenced using universal primers 27F/1492R. The 16S rRNA sequence was deposited in GenBank (MW725235) and showed 99% nucleotide similarity with Xanthomonas fragariae strain LMG 708 (NR_026318). The isolate’s identity was further confirmed by X. fragariae-specific primers XF9/XF12 (Roberts et al. 1996). All five isolates could be detected by XF9/XF12 primer. To confirm Koch’s postulates, five healthy strawberry plants were placed in 1000 ml glass beakers by submerging the cutting wound in 50 ml the bacterial suspension of 108 CFU/ml. Five additional strawberry plants treated with sterilized water served as a control. The beakers containing inoculated plants were sealed with plastic film at 25°C. Water-soaked rot appeared on internal tissue of crown similar to those observed in the field within 10-12 days after inoculation, while the control samples remained healthy. The bacteria were re-isolated from rot of inoculated crowns, and confirmed by X. fragariae-specific primers XF9/XF12. X. fragariae has been reported to cause angular leaf spot on strawberry in China (Wang et al. 2017; Wu et al., 2020). It’s also found that X. fragariae could systematically infect crown tissue (Milholland et al. 1996; Mahuku and Goodwin, 1997). To our knowledge, this is the first report of X. fragariae causing strawberry crown rot in China. This report increased our understanding of X. fragariae, and showed that the spread of this disease might seriously threaten the development of strawberry industry in the future

scholarly journals First Report of Meloidogyne graminicola on Rice in Henan Province, China

Plant Disease ◽  
2021 ◽  
Author(s):  
Mao-Yan Liu ◽  
Jing Liu ◽  
Wenkun Huang ◽  
Deliang Peng
Keyword(s):  
Oryza Sativa ◽  
Its Region ◽  
Henan Province ◽  
Morphological Data ◽  
Post Inoculation ◽  
Root Tips ◽  
Lateral Field ◽  
First Report ◽  
Meloidogyne Graminicola ◽  
Rice Plants

Rice (Oryza sativa) is an important food crop in China and root-knot nematode Meloidogyne graminicola has been one of the most important diseases on rice in recently five years (Ju et al. 2020). In August 2020, rice plants were found to be maldeveloped, yellow leaves and hooked root tips in an irrigated paddy field of Yuanyang County, Xinxiang City, Henan Province. Fifty rice plants were randomly collected and 84.0 percent plants were infected with root-knot nematodes, with root-gall index of 56.0. Then nematodes from rice roots were isolated with 100-μm and 25-μm sieves. A large number of females, some third-stage juveniles (J3s), and a small number of males of Meloidogyne spp. were found in root galls of all samples after dissected, and then were identified and measured under the microscope. In females (n = 20), the perineal pattern was dorsoventrally oval with low and round dorsal arch, and the lateral field was not obvious or absent, striae are usually smooth, with occasional short and irregular striatal fragmentation. The morphological data of females are as follows: body length (BL) = 516.9 ± 72.5 μm (424.2 to 611.6 μm), body width (BW)= 328.4 ± 80.7 μm (232.1 to 437.4 μm), stylet length = 11.2 ± 1.3 μm (7.7 to 13.9 μm), dorsal pharyngeal gland orifice to stylet base (DGO) = 3.9 ± 0.5 μm (3.2 to 4.5 μm), vulval slit length = 24.3 ± 4.6 μm (15.2 to 31.4 μm), vulval slit to anus distance = 16.2 ± 2.5 μm (10.1 to 20.2 μm). Males are long cylindrical, wormlike, with a short round tail. Morphological measurements of males (n = 20) were BL = 1,218.0 ± 150.7μm (1,085.7 to 1,692.2 μm), BW = 34.2 ± 4.6 μm (28.5 to 39.7 μm), stylet = 17.4 ± 0.7 μm (15.9 to 19.3 μm), DGO = 3.6 ± 0.7 μm (2.5 to 4.5 μm), tail = 10.8 ± 2.1 μm (8.0 to 14.8 μm), spicule = 30.3 ± 2.6 μm (24.7 to 36.3 μm). The egg masses from the females were incubated at 28℃ for 48 hours. Measurements of J2s (n = 20) were BL = 444.2 ± 37.8 μm (315.7 to 547.5 μm), BW = 21.2 ± 2.7 μm (16.7 to 26.4 μm), stylet = 14.2 ± 0.3 μm (13.6 to 14.8 μm), DGO = 3.5 ± 0.5 μm (2.7 to 4.5 μm), tail = 70.8 ± 5.1 μm (61.3 to 80.8 μm), hyaline tail length = 21.0 ± 2.5 μm (16.3 to 26.1 μm). These morphological features are consistent with the original description by Golden and Birchfield (1965). DNA of a single female from each sample was extracted for molecular identification. Primer pairs D2A/D3B (5´-ACAAGTACCGTGAGGGAAAGTTG-3´/ 5´-TCGGAAGGAACCAGCTACTA-3´) (De Ley et al. 1999) and the species-specific primers Mg-F3/Mg-R2 (5′-TTATCGCATCATTTTATTTG-3′/ 5′-CGCTTTGTTAGAAAATGACCCT-3′) (Htay et al. 2016) were used to amplify D2/D3 region of 28S RNA and the internal transcribed spacer (ITS) region, respectively. The amplified sequences of D2/D3 region (GenBank MW490724, 766 bp) shared 99.9% and 99.7% homology with the sequences of M. graminicola (MN647592, MT576694) isolated from Guangxi and Anhui Province (Ju et al. 2020), respectively, while ITS region sequences (MW487239, 369 bp) shared 100% and 99.7% homology to M. graminicola isolate GXL3 (MN636702) and FQJJ01 (MT159690), respectively. In order to verify the pathogenicity of nematodes, about 300 J2s were inoculated on ten 14-week-old rice (Oryza sativa cv. Nipponbare) planted in pots with sterilized sandy soil, respcectively, and maintained in a greenhouse at 28°C/26°C with a 16h/8h light/dark photoperiod and 75% relative humidity. At 14 days post inoculation, obvious symptoms of hook galls were observed on roots in all inoculated rice plants, and females and males in the same shape as the collected samples were found in the root galls under the stereoscopic microscope. No symptoms were observed on non-inoculated rice plants. After 28 days, the growth of the inoculated rice plants was significantly worse than that of uninoculated ones, with yellow leaves and short plants. These results confirmed the pathogenicity of M. graminicola on rice and it indicated that M. graminicola was already spread from the main rice-producing areas to the wheat and rice rotation areas. To our knowledge, this is the first report of M. graminicola in the Henan Province of China.

scholarly journals First report of stalk bacterial soft rot of sugarcane caused by Dickeya zeae in China

Plant Disease ◽  
2020 ◽  
Author(s):  
yanchang Yang ◽  
Ziting Yao ◽  
Mu-Qing Zhang ◽  
Chengwu Zou ◽  
Baoshan Chen
Keyword(s):  
Pure Water ◽  
Bacterial Species ◽  
Evolutionary Relationship ◽  
Soft Rot ◽  
Bacterial Suspension ◽  
Rrna Gene ◽  
Post Inoculation ◽  
Distilled Water ◽  
Sugarcane Cultivar ◽  
First Report

In late September 2019, seven stalks of about 1400 stalks of sugarcane cultivar Zhongzhe 1 exhibited soft rot symptoms in a trial plot in Beihai city, Guangxi province of China. Symptoms included scorched and collapsed leaves, maceration of stalks, and sour smelling exudates from the stalks (Supplementary Fig. S1). Severely diseased stalks had collapsed and were dead. Internal stalk fragments of 5 × 5 mm were collected at the junction of healthy and diseased tissue after surface-sterilization of stalks with 70% ethanol for one minute, and three times rinsing with sterile distilled water. Stalk fragments were placed on Luria–Bertani agar medium (1 % w/v tryptone, 0.5 % w/v yeast extract, 1 % w/v NaCl, 1 % w/v agar, pH7.0) and plates were put in an incubator at 30°C for 48h. Four types of bacterial colonies were obtained, and small and white colonies with irregular margins were the most dominant. A single colony of each type was diluted in sterile distilled water and aliquots of each suspension were streaked on fresh medium plates to obtain pure cultures. Ten eight-week-old stalks (11 th leaf stage) of sugarcane plants, which derived from cuttings of symptomless cultivar Zhongzhe 1, were inoculated by injection of 300 μl of bacterial suspension (3.5x108 CFU/ml) into the stalks. Another 10 stalks were injected with pure water and served as control. The inoculated plants were kept in a greenhouse at 25-37℃.Among the four types of bacteria, only strain BH9 induced symptoms that were identical to those of diseased canes observed in the field (Supplementary Fig. S1). Elongated water-soaked lesions were observed around the inoculation sites three days post inoculation. Five of the 10 BH9-inoculated plants had collapsed two days later. Water-soaked stalks had a sour smell similar to the filed diseased plants. Eight days post inoculation, all BH9-inoculated plants exhibited symptoms but control plants remained symptomless up to 30 days after inoculation. Uniform white colonies with irregular margins were isolated from the inoculated stalks that developed soft rot symptom, and these bacteria caused again stalk soft rot symptoms when inoculated to a new batch of 10 healthy plants. The 16S rRNA gene of strain BH9 was amplified by PCR with primer pair fD2/rP1 and the PCR amplicons from three independent colonies were sequenced. The sequences of the three amplicons were identical (Accession No. MT723897). BLAST alignments of the 16S rDNA sequence from BH9 strain with the GenBank database revealed that BH9 belonged to the genus Dickeya (98.5% identity between D. zeae BH9 and D. zeae EC1). Further PCR assays and sequencing of three genes, DNA polymerase III gamma subunit gene dnaX with primers dnaXf/dnaXr, DNA gyrase gene gyrB with primers gyrBf1/gyrBr1, and recombinase A gene recA with primers recAf/recAr, were performed to identify the species within the genus Dickeya (Zhang et al., 2014). BH9 sequences of these genes (Accession No. MT723898 to MT723900) had highest identity (97.5%, 97.6%, and 97.7%, respectively) with those from D. zeae EC1 (GenBank accession No. CP006929.1). To determine the evolutionary relationship of BH9 to other Dickeya species and strains, a phylogenetic analysis was performed using dnaX, gyrB, and recA sequences. As shown in Supplementary Fig. S2, BH9 clustered with D. zeae strains and formed a lineage distinguishable from other Dickeya species. Among the closest strains, D. zeae NCPPB3531 (Accession No. CM001980.1) was isolated from potato and D. zeae CSL RW192 (Accession No. CM001972.1) from river water (Pritchard et al., 2013). Consequently, strain BH9 was identified as D. zeae. This bacterial species has been reported to cause soft rot in rice (Pu et al., 2012), banana (Zhang et al., 2014), maize (Martinez-Cisneros et al., 2014), and clivia (Hu et al., 2018). To the best of our knowledge, this is the first report of a bacterial stalk rot caused by D. Zeae in sugarcane. In fact, low incidence of D. zeae-caused stalk soft rot was recently found in sugarcane fields in Fusui County, about 150 km north to Beihai. Given the potential threat of this disease to the local sugarcane industry, the mode of transmission, cultivar resistance, and measures to control the disease should be investigated.

scholarly journals Sphaerisporangium rufum sp. nov., an endophytic actinomycete from roots of Oryza sativa L

2014 ◽  
Vol 64 (Pt_4) ◽  
pp. 1077-1082 ◽  
Author(s):  
Ratchanee Mingma ◽  
Kannika Duangmal ◽  
Savitr Trakulnaleamsai ◽  
Arinthip Thamchaipenet ◽  
Atsuko Matsumoto ◽  
...  
Keyword(s):  
Oryza Sativa ◽  
Oryza Sativa L ◽  
Rrna Gene ◽  
Content Type ◽  
Endophytic Actinomycete ◽  
Link Type ◽  
Physiological Properties ◽  
Actinomycete Strain ◽  
Phosphatidylinositol Mannosides ◽  
The 16S Rrna Gene

An endophytic actinomycete, strain R10-82T, isolated from surface-sterilized roots of rice (Oryza sativa L.) was studied using a polyphasic approach. Strain R10-82T produced branching substrate mycelia and developed spherical spore vesicles on aerial hyphae containing non-motile spores. The major cellular fatty acids were iso-C16 : 0, iso-C14 : 0 and 10-methyl C17 : 0. The predominant menaquinones were MK-9, MK-9(H2), MK-9(H4) and MK-9(H6). Rhamnose, ribose, madurose, mannose and glucose were detected in whole-cell hydrolysates. The diagnostic phospholipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylinositol mannosides, hydroxylphosphatidylethanolamine and ninhydrin-positive phosphoglycolipids. These morphological and chemotaxonomic data were similar to those of the genus Sphaerisporangium . Analysis of the 16S rRNA gene sequence revealed that strain R10-82T was related most closely to Sphaerisporangium cinnabarinum JCM 3291T (98.3 % similarity). The DNA G+C content of strain R10-82T was 74 mol%. DNA–DNA relatedness data in combination with differences in the biochemical and physiological properties suggested that strain R10-82T should be classified as representing a novel species of the genus Sphaerisporangium , for which the name Sphaerisporangium rufum is proposed. The type strain is R10-82T ( = BCC 51287T = NBRC 109079T). An emended description of the genus Sphaerisporangium is also provided.

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