scholarly journals Grain Discoloration of Rice Caused by Pantoea ananatis (synonym Erwinia uredovora) in China

Plant Disease ◽  
2010 ◽  
Vol 94 (4) ◽  
pp. 482-482 ◽  
Author(s):  
H. Yan ◽  
S. H. Yu ◽  
G. L. Xie ◽  
W. Fang ◽  
T. Su ◽  
...  

In the autumn of 2008, a new bacterial disease of rice was noted in paddy fields near Hangzhou, Zhejiang Province, China. The disease caused severe discoloration of rice grains on cv. Zhong-zhe-you 1 (Oryza sativa L.). It often occurred at early flowering of hybrid rice. Initially, light, rusty, water-soaked lesions appeared on the lemma or palea and then turned brown. More immature and lighter grains were observed on panicles at harvest. No bacterial ooze was observed. Ten bacterial isolates were recovered from eight samples of discolored rice grains (1). Six isolates were selected for identification. They were similar to those of the reference strain of Pantoea ananatis (Serrano, synonym Erwinia uredovora) LMG 2665T (ATCC 33244) from Belgium in phenotypic tests based on the Biolog Microbial Identification System, version 4.2 (Biolog Inc., Hayward, CA), pathogenicity tests, gas chromatographic analysis of fatty acid methyl esters (FAME) using the Microbial Identification System (MIDI Inc, Newark, DE) with the aerobic bacterial library (TAB 5.0), and electron microscopy (TEM,KYKY-1000B, Japan). All isolates were facultatively anaerobic, gram-negative rods that measured 1.6 to 2.5 × 0.5 to 0.7 μm and had three to six peritrichous flagella. Colonies on nutrient agar were yellow and raised with smooth margins. A hypersensitive reaction was observed on tobacco (Nicotiana tobacum cv. Benshi) 24 h after inoculation. All isolates were identified as P. ananatis with Biolog similarity indices of 0.716 to 0.852 and FAME similarity indices of 0.783 to 0.903. Further identification as P. ananatis was done by 16S rDNA sequence analysis. Amplicons were produced from three strains using the universal primers (3) fD2: 5′-AGA GTT TGA TCA TGG CTC AG-3′ forward primer and rP1: 5′-ACG GTT ACC TTG TTA CGA CTT-3′ reverse primer and then sequenced (GenBank Accession Nos. GU324769, GU324770, and GU338399). A BlastN search of GenBank revealed that they had 97 to 98% nt identity with P. ananatis strain 3Pe76 (GenBank Accession No. EF178449). Koch's postulates were completed by spray inoculating panicles of rice cv. Zhong-zhe-you 1 at booting stage, grown in pots, with cell suspensions containing 108 CFU/ml of the six strains at 25 to 29°C. Three plants were inoculated with each strain, controls were sprayed with water, and the experiment was repeated once. Three weeks after inoculation, all strains produced symptoms on panicles similar to those observed in the field. Yellow pigmented bacteria were reisolated from symptomatic panicles and their identity was confirmed by FAMEs. These results indicate that the pathogen is P. ananatis (2), which also causes leaf blight and bulb decay of onion. To our knowledge, this is the first report of rice grain discoloration caused by P. ananatis in China. The disease cycle on rice and the control strategies in the regions are being further studied. References: (1) J. Y. Luo et al. Plant Dis. 91:1363, 2007. (2) H. G. Truper and L. de Clari. Int. J. Syst. Bacteriol. 47:908, 1997. (3) W. G. Weisburg et al. J. Bacteriol. 173:697, 1991.

Plant Disease ◽  
2009 ◽  
Vol 93 (11) ◽  
pp. 1214-1214 ◽  
Author(s):  
I.-S. Myung ◽  
J.-W. Kim ◽  
S. H. An ◽  
J. H. Lee ◽  
S. K. Kim ◽  
...  

In 2006 and 2007, a new bacterial disease was observed in field-cultivated soybeans in Boeun District and Munkyung City of Korea. The disease caused severe blighting of soybean (Glycine max) leaves. Soybean leaves in fields showed yellowish spots with brown centers. Brown and dead areas of variable size and shape were surrounded by wide, yellow haloes with distinct margins. Spots might coalesce and affected leaves fell readily. Seven bacterial strains were isolated from chlorotic areas of soybean leaves and all produced white colonies on trypticase soy agar. With the Biolog Microbial Identification System, version 4.2, (Biolog Inc., Hayward, CA) all strains and Pseudomonas syringae pv. tabaci CFBP2106T were identified as P. syringae pv. tabaci with a Biolog similarity index of 0.28 to 0.52 and 0.48 after 24 h. Pathogenicity of the strains (three plants per strain) on soybean leaves at the V5 stage (cv. Hwanggeum) was confirmed by rub inoculation with bacterial suspensions (1 × 108 CFU/ml) in sterile distilled water on the lesions cut 1 cm long on the upper side of the leaves with razor blades and by pinprick on 3-week-old leaves of tobacco (Nicotiana tabacum cv. Samsun) in the greenhouse. Wildfire symptoms on the soybean leaves and faint halos on tobacco leaves were observed 4 days after inoculation. The identification of reisolated bacterial strains was confirmed with the metabolic fingerprintings on Biolog. LOPAT tests (1) and phenotypic characteristics (3) of the strains were similar to those of the CFBP2106T. Colonies were levan positive, oxidase negative, potato soft rot negative, arginine dihydrase negative, and tobacco hypersensitivity negative. All strains were gram-negative, aerobic rods with a polar flagellum. Strains were negative for esculin hydrolysis, gelatin liquefaction, urea production, accumulation of poly-β-hydroxy butyrate, starch hydrolysis, ornithine dihydrolase, lysine dihydrolase, growth at 37°C, utilization of geraniol, benzoate, cellobiose, sorbitol, trehalose, l-rhamnose, and adonitol. Positive reactions were catalase and arbutin hydrolysis, utilization of sorbitol, d-arabinose, and dl-serine. The strains were variable in utilization of mannitol, sucrose, and d-arabinose. The 1,472-bp PCR fragments of strains, BC2366 (GenBank Accession No. FJ755788) and BC2367 (No. FJ755789) was sequenced using 16S rDNA universal primers (2). The sequences shared 100% identity with the analogous sequences of P. syringae pv. glycenea (GenBank Accession No. AB001443) available in NCBI databases. Based on the phenotypic, genetic, and pathological characteristics, all strains were identified as P. syringae pv. tabaci. To our knowledge, this is the first report of P. syringae pv. tabaci causing wildfire on soybean in Korea. References: (1) R. A. Lelliott et al. J. Appl. Bacteriol. 29:470, 1966. (2) I.-S. Myung et al. Plant Dis. 92:1472, 2008. (3) N. W. Schaad et al., eds. Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd ed. The American Phytopathological Society, St. Paul, MN, 2001.


Plant Disease ◽  
2008 ◽  
Vol 92 (5) ◽  
pp. 832-832 ◽  
Author(s):  
L. H. Xu ◽  
G. L. Xie ◽  
B. Li ◽  
B. Zhu ◽  
F. S. Xu ◽  
...  

In the spring of 2006, a new bacterial disease was noted in pear orchards near Hangzhou, Zhejiang Province, China. The disease caused severe blossom blast on pears (Pyrus pyrifolia; cv. Cuiguan). Early symptoms of the disease included blackening of the calyx end of developing fruit, blackening of blossom clusters while leaves of affected blossom clusters appeared normal, or death of clusters consisting of both blossoms and leaves. Later, tips of twigs turned dark brown and died. No bacterial ooze was observed. Twelve bacterial isolates were recovered from ten samples of buds and blossoms. Six isolates were selected for identification. They were similar to those of the reference strains of Pseudomonas syringae pv. syringae LMG5570 and LMG 2230 from Belgium in phenotypic tests on the basis of the Biolog Microbial Identification System (version 4.2; Biolog Inc., Hayward, CA), pathogenicity tests, gas chromatographic analysis of fatty acid methyl esters (FAMEs) using the Microbial Identification System (MIDI Inc., Newark, DE) with aerobic bacterial library (TABA50), and electron microscopy (TEM, KYKY-1000B, Japan). All isolates tested were gram-negative, aerobic rods measuring 1.5 to 2.4 × 0.5 to 0.6 μm with 2 to 4 polar flagella. Fluorescent green diffusible pigment was produced on King's Medium B. Colonies were gray-white and slightly raised with smooth margins on nutrient agar. They produced levan on sucrose nutrient agar. A hypersensitive reaction was observed on tobacco cv. Benshi 24 h after inoculation. All isolates were identified as P. syringae pv. syringae with Biolog similarity index of 0.57 to 0.86 and FAME similarity index of 0.58 to 0.81. Identification as P. syringae pv. syringae was confirmed using 16S rDNA universal primers (2,3): 5′-AGA GTT TGA TCA TGG CTC AG-3′ forward primer, 5′-ACG GTT ACC TTG TTA CGA CTT-3′ reverse primer. The PCR fragments of the three isolates were sequenced and compared with sequences in GenBank. They had 99% similiarity with P. syringae pv. syringae 16S rRNA gene strain NCPPB 3869. Koch's postulates were conducted on buds of the original pear cultivar growing in pots and detached pear blossoms in flasks by spray inoculation with cell suspensions containing 108 CFU/ml of the six isolates at 18 to 22°C with two replications. The bacteria induced symptoms on buds and blossoms similar to those observed in the field. The bacterium was reisolated from symptomatic pear buds and internal ovary tissues. P. syringae pv. syringae was first reported in England as the cause of pear blossom blast in 1914 (1). After searching all the Chinese agricultural databases and major journals (National Knowledge Infrastructure database, Vip Chinese periodical database, Chinese wanfang database, China InfoBank, Scientia Agricultura Sinica, Acta Phytopathologica Sinica, Acta Phytophylacica Sinica, and Journal of Fruit Science), to our knowledge, this is the first report of pear blossom blast caused by P. syringae pv. syringae in China. The disease cycle on pear trees and the control strategies in the regions are being further studied. References: (1) B. P. Barker et al. Ann. Appl. Biol. 1:85, 1914. (2) U. Edward et al. Nucleic Acids Res. 17:7843,1989. (3) B. Li et al. J. Phytopathol. 34:141, 2006.


Author(s):  
Benzhong Fu ◽  
Lei Yu ◽  
Bokai Wang ◽  
Cao Zheng

Walnut blight caused by Xanthomonas arboricola pv. juglandis (Xaj) is the most important bacterial disease in walnut production worldwide. To seek biocontrol agents against Xaj, we screened 152 endophytic bacteria isolated from 87 plants. Through dual-culture method screening, we obtained four antagonistic bacteria, ATE17, BME17, CIE17, and OFE17 which were isolated from Amaranthus tricolor, Bambusa multiplex, Canna indica, and Osmanthus fragrans plants respectively. The inhibition ratios of ATE18, BME17, CIE18, and OFE17 against Xaj on plates were 1.5, 1.6, 1.3, and 1.6, respectively. These indicated they have good biocontrol potential for walnut bacterial blight. Subsequently, the four endophytic bacteria were identified by morphology, Gram staining, Microbial Identification System (fatty acid methyl ester analysis), as well as 16S rDNA and gyrB sequencing. It turns out that all four strains were identified as Bacillus sp. Furthermore, the two strains BME17 and OFE17 can suppress multiple plant fungal pathogens and bacterial pathogens on plates.


2020 ◽  
Vol 12 (2) ◽  
pp. 552 ◽  
Author(s):  
Weronika Kruszelnicka ◽  
Andrzej Marczuk ◽  
Robert Kasner ◽  
Patrycja Bałdowska-Witos ◽  
Katarzyna Piotrowska ◽  
...  

Strength properties of grains have a significant impact on the energy demand of grinding mills. This paper presents the results of tests of strength and energy needed the for destruction of rice grains. The research aim was to experimentally determine mechanical and processing properties of the rice grains. The research problem was formulated in the form of questions: (1) what force and energy are needed to induce a rupture of rice grain of the Oryza sativa L. of long-grain variety? (2) what is the relationship between grain size and strength parameters and the energy of grinding rice grain of the species Oryza sativa L. long-grain variety? In order to find the answer to the problems posed, a static compression test of rice grains was done. The results indicate that the average forces needed to crush rice grain are 174.99 kg m·s−2, and the average energy is 28.03 mJ. There was no statistically significant relationship between the grain volume calculated based on the volumetric mass density Vρ and the crushing energy, nor between the volume Vρ and other strength properties of rice grains. In the case of Vs, a low negative correlation between strength σmin and a low positive correlation between the power inducing the first crack were found for the grain size related volume. A low negative correlation between the grain thickness a3, stresses σmin and work WFmax was found as well as a low positive correlation between thickness a3 and the force inducing the first crack Fmin.


2013 ◽  
Vol 634-638 ◽  
pp. 1179-1183 ◽  
Author(s):  
Jing Deng ◽  
Hua Chang Wu ◽  
Xing Xiu Zhao ◽  
Jiao Jiao Shi

Sufu is a traditional Chinese fermented food. The safety of spontaneous fermentation products has been concerned by more and more people. A total of four isolates with big clear halos on the casein medium plate were isolated from spontaneous fermented Sufu in southern Sichuan. A1 and A3 most likely belong to Bacillus cereus B according to their phenotype and Biolog Microbial Identification System. B2 was classified in group as Bacillus amyloliquefaciens B with the same methods. A2 was identified as Bacillus subtilis according to their phenotype and 16SrRNA. The safety of the strains are also discussed.


1992 ◽  
Vol 58 (6) ◽  
pp. 2089-2092 ◽  
Author(s):  
J M Klingler ◽  
R P Stowe ◽  
D C Obenhuber ◽  
T O Groves ◽  
S K Mishra ◽  
...  

Plant Disease ◽  
2008 ◽  
Vol 92 (3) ◽  
pp. 483-483 ◽  
Author(s):  
G. F. Wang ◽  
K. Praphat ◽  
G. L. Xie ◽  
B. Zhu ◽  
B. Li ◽  
...  

In August of 2006, a new bacterial disease was noted in Hangzhou mulberry orchards of Zhejiang Province, China where bacterial wilt of mulberry caused by Ralstonia solanacearum was previously reported (3). In the summer, the disease caused severe wilt, especially on 1- or 2-year-old mulberry plants, that resulted in premature plant death. Leaf wilt symptoms generally started on older leaves at the bottom of the plant and spread to the younger leaves. The leaves of infected plants became withered and dry, turned dark brown, and eventually the plants became defoliated. The root xylem of infected plants was moist and discolored with brown stripes. The phloem was asymptomatic, however, in severe infections, the phloem was decayed. The observation of wilting proceeding from the bottom of the plant to the top distinguishes this disease from bacterial wilt caused by R. solanacearum. Five bacterial strains isolated from infected mulberry plants showed characteristics similar to those of the standard reference strain of Enterobacter cloacae subsp. cloacae IBJ0611from China, but differed from R. solanacearum IBJ35, E. cancerogenus LMG2693T, and E. cloacae subsp. dissolvens LMG2683T from the University of Gent, Belgium in phenotypic tests, including the Biolog Identification System version 4.2 (Biolog Inc., Hayward CA), pathogenicity tests, transmission electron microscopy (TEM,KYKY-1000B, Japan) observation, and gas chromatographic analysis of fatty acid methyl esters (FAMEs) using the Microbial Identification System (MIDI Company, Newark, DE) with the aerobic bacterial library (TABA50). Isolates were gram negative, facultative anaerobic, rod shaped, 0.3 to 1.0 × 1.0 to 3.0 μm with peritrichous flagella. Colonies on nutrient agar were light yellow, smooth, circular, entire, and convex with no green fluorescent diffusible pigment on King's medium B (3). Weak hypersensitive reaction was observed on tobacco 3 days after inoculation. All five strains were identified as E. cloacae with Biolog similarity of 0.662 to 0.863 and FAMEs similarity of 0.632 to 0.701. Inoculation of 10 6-month-old intact mulberry plants of cv Husang with cell suspensions containing 109 CFU/ml by pinprick at the base of the stem reproduced symptoms observed in natural infections. No symptoms were noted on the two control plants inoculated by the same method but with sterilized distilled water. The bacterium was reisolated from the symptomatic mulberry plants. E. cloacae has been reported from the United States as the cause of internal yellowing of papaya fruits (1) and rhizome rot of edible ginger (2). To our knowledge, this is the first report of mulberry wilt caused by E. cloacae in China. References: (1) K. Nishijima et al. Plant Dis. 71:1029, 1987. (2) K. Nishijima et al. Plant Dis. 88:1318, 2004. (3) L. Xu et al. Acta Phytophylacica. Sin. 34:141, 2007.


2016 ◽  
Vol 369 ◽  
pp. 148-151
Author(s):  
J.V. Silva ◽  
C.M.R. Franco ◽  
E.M.A. Pereira ◽  
T.H.F. Andrade ◽  
A.G. Barbosa de Lima

Rice (Oryza sativa L.) is a greatly important socio-economic crop. Immediate threshing and drying of wet harvested grains, to reach 18–19% (w.b) moisture content, is a practical method used by individual farmers to slow deterioration and increase selling prices. However, rough rice grain is different from other grains because it has an outer cover shell (palea and lemma) and a bran layer. Thus, the heat and mass transfer processes that take place during grain drying are different from those of other cereal grains, so understanding the effect of different treatments, drying temperature, moisture content and the gradients in rice grains is essential to optimize the drying conditions. In this sense, the current study aims to analyze the moisture removal and its effects on the stress cracking and the number of brown rice grains (BRSMG CONAI variety) at the temperatures of 60 and 80°C.


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