Xanthomonas oryzae pv. oryzicola (bacterial leaf streak of rice)
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Distribution Table
- Risk of Introduction
- Hosts/Species Affected
- Host Plants and Other Plants Affected
- Growth Stages
- List of Symptoms/Signs
- Biology and Ecology
- Seedborne Aspects
- Pathway Vectors
- Plant Trade
- Detection and Inspection
- Similarities to Other Species/Conditions
- Prevention and Control
- Distribution Maps
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PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Xanthomonas oryzae pv. oryzicola (Fang et al. 1957) Swings et al. 1990
Preferred Common Name
- bacterial leaf streak of rice
Other Scientific Names
- Xanthomonas campestris pv. oryzicola (Fang et al. 1957) Dye 1978
- Xanthomonas oryzicola Fang, Ren, Chen, Chu, Faan & Wu 1957
- Xanthomonas translucens f.sp. oryzicola (Fang et al.) Bradbury 1971
International Common Names
- Spanish: estrías bacterianas del arroz; quemaduras bacterianas del arroz
- French: briûlure bactérienne du riz; stries bactériennes du riz
- XANTTO (Xanthomonas oryzae pv. oryzicola)
Taxonomic TreeTop of page
- Domain: Bacteria
- Phylum: Proteobacteria
- Class: Gammaproteobacteria
- Order: Xanthomonadales
- Family: Xanthomonadaceae
- Genus: Xanthomonas
- Species: Xanthomonas oryzae pv. oryzicola
Notes on Taxonomy and NomenclatureTop of page
The two bacteria causing distinct diseases in rice were formerly named as pathovars of Xanthomonas campestris, as were most other plant-pathogenic Xanthomonas strains. The two pathovars pv. oryzae and pv. oryzicola are now classified in the species Xanthomonas oryzae (Swings et al., 1990). Vauterin et al. (1995) confirmed the present taxonomic position of this and other species of Xanthomonas by molecular and biochemical methods.
DescriptionTop of page X. oryzae pv. oryzicola is a Gram-negative, encapsulated rod with a single polar flagellum for motility. Cell dimensions are 1.0-2.5 x 0.4-0.6 µm. Colonies are fairly slow-growing, usually pale-yellow, round, smooth, entire, domed and mucoid.
DistributionTop of page
See also CABI/EPPO (1998, No. 286).
Distribution TableTop of page
The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
|Continent/Country/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Reference||Notes|
|Bangladesh||Restricted distribution||EPPO, 2014; CABI/EPPO, 2015|
|Cambodia||Widespread||EPPO, 2014; CABI/EPPO, 2015|
|China||Restricted distribution||EPPO, 2014; CABI/EPPO, 2015|
|-Fujian||Present||EPPO, 2014; CABI/EPPO, 2015|
|-Guangdong||Present||EPPO, 2014; CABI/EPPO, 2015|
|-Guizhou||Present||Wang et al., 2010; CABI/EPPO, 2015|
|-Hainan||Present||EPPO, 2014; CABI/EPPO, 2015|
|-Hunan||Present||Ren et al., 1993; EPPO, 2014; CABI/EPPO, 2015|
|-Jiangsu||Present||Chen et al., 2009; CABI/EPPO, 2015|
|-Sichuan||Present||Wang et al., 2010; CABI/EPPO, 2015|
|-Yunnan||Present||Wang et al., 2010; CABI/EPPO, 2015|
|-Zhejiang||Present||EPPO, 2014; CABI/EPPO, 2015|
|India||Widespread||EPPO, 2014; CABI/EPPO, 2015|
|-Andhra Pradesh||Present||CABI/EPPO, 2015|
|-Bihar||Present||EPPO, 2014; CABI/EPPO, 2015|
|-Karnataka||Present||EPPO, 2014; CABI/EPPO, 2015|
|-Madhya Pradesh||Present||EPPO, 2014; CABI/EPPO, 2015|
|-Maharashtra||Present||EPPO, 2014; CABI/EPPO, 2015|
|-Uttar Pradesh||Present||EPPO, 2014; CABI/EPPO, 2015|
|-West Bengal||Present||EPPO, 2014; CABI/EPPO, 2015|
|Indonesia||Widespread||EPPO, 2014; CABI/EPPO, 2015|
|-Java||Present||EPPO, 2014; CABI/EPPO, 2015|
|-Kalimantan||Present||EPPO, 2014; CABI/EPPO, 2015|
|-Sulawesi||Present||EPPO, 2014; CABI/EPPO, 2015|
|-Sumatra||Present||EPPO, 2014; CABI/EPPO, 2015|
|Japan||Absent, reported but not confirmed||CABI/EPPO, 2015|
|Laos||Restricted distribution||EPPO, 2014; CABI/EPPO, 2015|
|Malaysia||Widespread||EPPO, 2014; CABI/EPPO, 2015|
|-Peninsular Malaysia||Present||EPPO, 2014; CABI/EPPO, 2015|
|-Sabah||Present||EPPO, 2014; CABI/EPPO, 2015|
|-Sarawak||Present||EPPO, 2014; CABI/EPPO, 2015|
|Myanmar||Present||Kush, 1977; EPPO, 2014; CABI/EPPO, 2015|
|Nepal||Present||EPPO, 2014; CABI/EPPO, 2015|
|Pakistan||Present||Kush, 1977; EPPO, 2014; CABI/EPPO, 2015|
|Philippines||Present||EPPO, 2014; CABI/EPPO, 2015|
|Taiwan||Absent, reported but not confirmed||EPPO, 2014; CABI/EPPO, 2015|
|Thailand||Present||EPPO, 2014; CABI/EPPO, 2015|
|Vietnam||Widespread||EPPO, 2014; CABI/EPPO, 2015|
|Burkina Faso||Restricted distribution||Wonni et al., 2011; EPPO, 2012; EPPO, 2014; CABI/EPPO, 2015|
|Burundi||Restricted distribution||Afolabi et al., 2014a; CABI/EPPO, 2015|
|Kenya||Present||2016||Onaga et al., 2018|
|Madagascar||Present||Buddenhagen, 1985; EPPO, 2014; CABI/EPPO, 2015|
|Mali||Restricted distribution||EPPO, 2012; EPPO, 2014; CABI/EPPO, 2015|
|Nigeria||Present||EPPO, 2014; CABI/EPPO, 2015|
|Senegal||Present||Trinh, 1980; EPPO, 2014; CABI/EPPO, 2015|
|Uganda||Restricted distribution||Afolabi et al., 2014a; CABI/EPPO, 2015|
|Russian Federation||Absent, formerly present||EPPO, 2014|
|-Russian Far East||Absent, formerly present||EPPO, 2014|
|Australia||Restricted distribution||EPPO, 2014; CABI/EPPO, 2015|
|-Australian Northern Territory||Present||Bradbury, 1986; EPPO, 2014; CABI/EPPO, 2015|
Risk of IntroductionTop of page Risk Criteria Category
Economic Importance Low
Distribution Asia, Africa, Europe, Australia
Seedborne Incidence Low
Seed Transmitted Yes
Seed Treatment None
Overall Risk Low
Hosts/Species AffectedTop of page
Rice is the principal host: the japonica race is usually more resistant than indica to X. oryzae pv. oryzicola.
This pathogen may also infect Leersia sp(p)., Leptochloa filiformis [L. mucronata], wild and cultivated species of Oryza, Paspalum orbiculare, Zizania palustris and Zoysia japonica (EPPO/CABI, 1992; EPPO 1995).
Host Plants and Other Plants AffectedTop of page
Growth StagesTop of page Vegetative growing stage
SymptomsTop of page X. oryzae pv. oryzicola causes narrow, dark-greenish, water-soaked, interveinal streaks of various lengths, initially restricted to the leaf blades. The lesions enlarge, turn yellowish-orange to brown (depending on cultivar), and eventually coalesce. Tiny amber droplets of bacterial exudate are often present on the lesions. There are no records of symptoms on infected seeds.
In its advanced stages, the disease is difficult to distinguish from leaf blight caused by X. oryzae pv. oryzae, but lesion margins remain linear rather than wavy as for the latter. Direct observation of the bacteria may be necessary for confirmation.
Damage is often associated with lepidopteran leaf rollers, leaf-folders and hispa beetles, since bacteria readily enter the damaged tissue caused by insect infestation. (From EPPO/CABI, 1992.)
List of Symptoms/SignsTop of page
|Leaves / abnormal colours|
|Leaves / necrotic areas|
|Leaves / odour|
|Leaves / yellowed or dead|
Biology and EcologyTop of page The importance of seed as an inoculum source for X. oryzae pv. oryzicola is recognized, but the role of weeds in off-season survival is not known. Seed transmission may not be important for off-season (winter) crops sown with seed produced in the main season (summer), because the disease does not develop in cool, dry conditions (Rao, 1987). Survival occurs from season to season on crop debris, but not in soil (Devadath and Dath, 1970).
There is undoubtedly spread in irrigation water and infection is favoured with rain and under high humidity.
The bacterium enters leaves through stomata and wounds (particularly those from insect attack) and multiplies in the sub-stomatal cavity and intercellular spaces in the parenchyma. Eventually, parenchyma is replaced by bacterial masses. After lesions (streaks) form, bacterial exudate forms on the leaf surface under moist conditions during the night.
Seedborne AspectsTop of page
X. oryzae pv. oryzicola can be detected in rice seeds (Xie et al., 1990, 1991; Ming et al., 1991). A field survey of rice bacterial diseases and their causal organisms was conducted in Zhejiang, China (subtropical) and Luzon, Philippines (tropical) during 1993-1998. Two hundred and eighty pathogenic bacterial isolates were screened from over 3500 isolates associated with rice seeds from 116 seed samples collected in the subtropics and 129 seed samples from the tropics. The data revealed that bacterial leaf blight (Xanthomonas oryzae pv. oryzae) and bacterial leaf streak (X. oryzae pv. oryzicola) are important in the two zones (Xie et al., 1999).
One report stated that X. oryzae pv. oryzicola is transmitted by infested seed from one summer season to the next, but the disease cycle is broken if summer seed is sown in the winter season because the pathogen cannot become established during the cool, dry, winter weather (Rao, 1987).
Seed Health Tests
Pathogenicity test (Cottyn et al., 1994)
10 ml sterile water with 0.85% NaCl is poured into a culture slant and the bacterial mass is scraped off. The resulting suspension is adjusted to 10<(sup)8>-10<(sup)9> c.f.u./ml, then placed in a drop of Tween and atomized onto IR24 or IR50 plants. The plants are maintained in a greenhouse and examined for bacterial streak lesions 10 days after inoculation. Bacteria are reisolated from the lesions and their virulence confirmed by repeating the pathogenicity test.
Use of semi-selective medium (Ming et al., 1991).
A semi-selective medium, called XOS, has been developed to isolate X. oryzae pv. oryzae and X. oryzae pv. oryzicola from rice seed. The medium contains sucrose, peptone, monosodium glutamate, calcium nitrate, potassium phosphate, iron EDTA, cycloheximide, cephalexin, kasugamycin, methyl violet 2B and agar. Recovery of X. oryzae pv. oryzae, X. oryzae pv. oryzicola and non-pathogenic Xanthomonas-like bacteria on XOS basal medium ranged from 98 to 162% (mean 121%) of the recovery on nutrient glucose agar after incubation at 28°C for 4 days. Addition of the selective inhibitors decreased recovery of non-Xanthomonas saprophytes in rice seed extracts by more than 53%, compared with XOS basal medium. Several saprophytic bacteria common to some Chinese seed lots were not significantly reduced; however, the growth of such bacteria was decreased enough to allow detection of the slower growing xanthomonads. Recovery of different pathogenic strains of the rice xanthomonads varied significantly on XOS. Detection of Xanthomonas species from seed was dependent on partial maceration of seed and incubation of the resulting extract at 5°C for 2 h. Extracts from rice seed collected from asymptomatic plants in California, USA, and China and from plants with symptoms of bacterial leaf blight in China were plated on XOS, and colonies suggestive of Xanthomonas were isolated. Various identification assays indicated that these strains belonged to the genus Xanthomonas; however, the strains were non-pathogenic when inoculated on a susceptible rice cultivar. It is concluded that XOS is quantitatively and qualitatively superior to other available media for isolation of Xanthomonas species from seed. Pathogenicity tests are needed after Xanthomonas species have been isolated to confirm that they are X. oryzae [X. oryzae pv. oryzae or X. oryzae pv. oryzicola].
Leaf inoculation (Xie and Mew, 1998)
The method is based on inoculating leaf segments on agar with seed washings in a moist chamber. Freshness of inoculated leaf segments is maintained by addition of 75 to 100 p.p.m. benzimidazole to the 1% water agar after sterilization. Using cells from pure cultures, the minimum inoculum concentration to initiate leaf streak lesions on the segments was found to be 103 c.f.u./ml. Inoculum prepared from seeds harvested from severely infected mother plants induced lesions typical of leaf streak, followed by bacterial ooze. With 4 g of seed, the incubation period was 3.5 days and bacterial ooze appeared within 5 days. The minimum amount of seed needed to detect the bacterium based on seed washings varied according to disease severity of the mother plants. The bacteria isolated from lesions on the leaf segments were confirmed as X. oryzae pv. oryzicola after bacteriological, serological and Biolog tests were conducted. The results confirm that the detached-leaf method is as simple and reliable as the immuno-radiometric assay and inoculation on intact pot-grown rice plants in the greenhouse.
Serological tests (Xie et al., 1990)
Using an immunoradiometric assay (IRMA) about 1000 bacterial cells/ml of X. oryzae pv. oryzicola were detected in the rice seed samples examined. The antiserum and labelled protein A were stable and there was only a slight cross-reaction with X. oryzae pv. oryzae. A batch of seeds could be inspected in 4.5 h.
Plant TradeTop of page
|Plant parts liable to carry the pest in trade/transport||Pest stages||Borne internally||Borne externally||Visibility of pest or symptoms|
|Leaves||Yes||Pest or symptoms usually visible to the naked eye|
|True seeds (inc. grain)||Yes||Pest or symptoms usually invisible|
|Plant parts not known to carry the pest in trade/transport|
|Fruits (inc. pods)|
|Stems (above ground)/Shoots/Trunks/Branches|
ImpactTop of page Bacterial leaf streak of rice (caused by X. oryzae pv. oryzicola) is much less important than bacterial leaf blight (X. oryzae pv. oryzae), generally occurring in some areas during very wet seasons and where high rates of nitrogen fertilizer are used. Severe disease conditions are usually observed in the early stages of growth, older plants becoming more resistant. High grain losses due to the disease are therefore rare, because plants have time to recover after a disease outbreak. Losses of up to 30% have been reported in India, but losses are usually lower (Ou, 1985).
DiagnosisTop of page
A diagnostic protocol for X. oryzae pv. oryzicola is given in OEPP/EPPO (2007).
If a pure culture of the right colony type is isolated from rice tissue with symptoms of bacterial leaf streak, an initial diagnosis may be made if the organism is shown to be Xanthomonas (no growth with 0.1% tetrazolium salt, negative for nitrate reduction, etc.; Lelliott and Stead, 1987). Diagnosis is confirmed by testing pathogenicity on rice and/or by complete identification as X. oryzae pv. oryzicola, including positive reactions in starch and gelatin hydrolysis tests (Bradbury, 1986).
Detection and InspectionTop of page Detection in seed is of primary importance in preventing the spread of X. oryzae pv. oryzicola. Preliminary indications of seed infection are given by bacterial streaming. The bacterium can be isolated by dilution methods and confirmed by standard methods (see Diagnostic Methods).
A semi-selective medium for the two pathovars of X. oryzae has been described (Ming et al., 1991). However, serological methods that reliably distinguish pv. oryzicola from pv. oryzae (much more widely distributed) have been lacking. A specific immunoradiometric assay for pv. oryzicola in seed, with reportedly only slight cross-reaction with pv. oryzae, has been published (Xie et al., 1990).
Similarities to Other Species/ConditionsTop of page X. oryzae pv. oryzicola may be distinguished from X. oryzae pv. oryzae (cause of bacterial leaf blight) by colony morphology in typical isolates, by strong starch and gelatin hydrolysis (see Diagnostic Methods) and by modern biochemical and molecular methods (Leach et al., 1990; Swings et al., 1990).
X. oryzae pv. oryzicola was formerly classified as a pathovar of X. campestris, but the pathogens that cause bacterial leaf blight and leaf streak of rice are now placed in the species X. oryzae.
Prevention and ControlTop of page Phytosanitary measures to prevent the distribution of seed infected by X. oryzae pv. oryzicola are of primary importance for the control of bacterial leaf streak. If healthy seed is used, other control measures are not likely to be necessary.
Apart from the relative resistance of japonica races of rice compared to indica races, there is little reference to resistance as a method of control.
ReferencesTop of page
Afolabi O, Milan B, Amoussa R, Koebnik R, Szurek B, Habarugira G, Bigirimana J, Silue D, 2014. First report of Xanthomonas oryzae pv. oryzicola causing bacterial leaf streak of rice in Burundi. Plant Disease, 98(10):1426. http://apsjournals.apsnet.org/loi/pdis
Afolabi O, Milan B, Poulin L, Ongom J, Szurek B, Koebnik R, Silue D, 2014. First report of Xanthomonas oryzae pv. oryzicola causing bacterial leaf streak of rice in Uganda. Plant Disease, 98(11):1579. http://apsjournals.apsnet.org/loi/pdis
APPPC, 1987. Insect pests of economic significance affecting major crops of the countries in Asia and the Pacific region. Technical Document No. 135. Bangkok, Thailand: Regional Office for Asia and the Pacific region (RAPA).
Chen ZhiYi, Liu YongFeng, Liu FengQuan, Luo ChuPing, Nie YaFeng, 2009. Resistant evaluation of rice bacterial leaf streak and virulence differentiation of Xanthomonas oryzae pv. oryzicola in Jiangsu. Acta Phytophylacica Sinica, 36(4):315-318. http://www.wanfangdata.com.cn
EPPO, 2012. EPPO Reporting Service. EPPO Reporting Service. Paris, France: EPPO. http://archives.eppo.org/EPPOReporting/Reporting_Archives.htm
EPPO, 2014. PQR database. Paris, France: European and Mediterranean Plant Protection Organization. http://www.eppo.int/DATABASES/pqr/pqr.htm
Leach JE, White FF, Rhoads ML, Leung H, 1990. A repetitive DNA sequence differentiates Xanthomonas campestris pv. oryzae from other pathovars of X. campestris. Molecular Plant-Microbe Interactions, 3(4):238-246
Onaga, G., Murori, R., Habarugira, G., Nyongesa, O., Bigirimana, J., Oliva, R., Cruz, C. V., Onyango, G., Andaku, J., Ongom, J., 2018. First report of Xanthomonas oryzae pv. oryzicola causing bacterial leaf streak of rice in Kenya., 102(5), 1025. http://apsjournals.apsnet.org/loi/pdis doi: 10.1094/PDIS-06-17-0846-PDN
Swings J, Mooter M van den, Vauterin L, Hoste B, Gillis M, Mew TW, Kersters K, 1990. Reclassification of the causal agents of bacterial blight (Xanthomonas campestris pv. oryzae) and bacterial leaf streak (Xanthomonas campestris pv. oryzicola) of rice as pathovars of Xanthomonas oryzae (ex Ishiyama 1922) sp. nov., nom. rev. International Journal of Systematic Bacteriology, 40(3):309-311
Wang ShaoXue, Ma GaiZhuan, Wei LanFang, Ji GuangHai, 2010. Virulence differentiation of strains of Xanthomonas oryzae pv. oryzicola in southwest of China. Journal of Hunan Agricultural University, 36(2):188-191. http://www.hunau.net/qks
Wonni I, Ouedraogo L, Verdier V, 2011. First report of bacterial leaf streak caused by Xanthomonas oryzae pv. oryzicola on rice in Burkina Faso. Plant Disease, 95(1):72-73. http://apsjournals.apsnet.org/loi/pdis
Xie GL, Sun SY, Wang GJ, Zhu XD, Chen JA, Ye YH, Feng ZM, Liang MX, 1990. Studies on rice seed inspection of Xanthomonas campestris pv. oryzicola. 1. Immunoradiometric assay. Chinese Journal of Rice Science, 4(3):127-132
Distribution MapsTop of page
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