Phosphate Solubilizing Ability and Phylogenetic Diversity of Bacteria from P-Rich Soils Around Dianchi Lake Drainage Area of China

The phylogenetic diversity of phosphate solubilizing bacteria(PSB)distributed in P-rich soils in the Dianchi Lake drainage area of China was characterized,and the tricalcium phosphate(TCP)solubilizing activities of isolated PSB were determined.Among 1 328 bacteria isolated from 100 P-rich soil samples,377 isolates(28.39%of the total)that exhibited TCP solubilization activity were taken as PSB.These PSB showed different abilities to solubilize TCP,with the concentrations of solubilized P in bacterial cultures varying from 33.48 to 69.63 mg L^-1.A total of 123 PSB isolates,with relatively high TCP solubilization activity(>54.00 mg L^-1),were submitted for restriction fragment length polymorphism(RFLP)analysis,which revealed 32 unique RFLP patterns.Based on these patterns,62 representative isolates,one to three from each RFLP pattern,were seffected for 16S rRNA sequencing.Phylogenetic analysis placed the 123 PSB into three bacterial phyla,namely Proteobacteria,Actinobacteria and Firmicutes.Members of Proteobacteria were the dominant PSB,where 107 isolates represented by 26 RFLP patterns were associated with the genera of Burkholderia,Pseudomonas,Acinetobacter,Enterobacter,Pantoea,Serratia,Klebsiella,Leclercia,Raoultella and Cedecea.Firmicutes were the subdominant group,in which 13 isolates were affiliated with the genera of Bacillus and Brevibacterium.The remaining 3 isolates were identified as three species of the genus Arthrobacter.This research extends the knowledge on PSB in P-rich soils and broadens the spectrum of PSB for the development of environmentally friendly biophosphate fertilizers.     

应用新引物DGGE分析土壤中硝酸盐还原细菌群落

The narG gene is frequently used as a molecular marker for bacterial nitrate-reducing community analysis. In this study, a new set of primers targeting the narG gene was designed and applied to semi-nested polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) assay. The potential of the new primers was verified on DNA directly extracted from soils from five different experimental sites distributed in Central and Southern Italy. Specificity of the primers was determined by excision, amplification, and sequencing of bands resolved by DGGE. A phylogenetic analysis showed the correlation between the sequences retrieved from the soils studied and the narG sequences from β and γ-Proteobacteria. These primers expanded the existing molecular tools for ecological study on the size and diversity of nitrate-reducing bacterial community in soil.     

蘑菇生长过程中覆土内微生物群落结构的变化特征

The culturable bacterial population and phospholipid fatty acid (PLFA) profile of casing soil were investigated at different mushroom (Agaricus bisporus) cropping stages. The change in soil bacterial PLFAs was always accompanied by a change in the soil culturable bacterial population in the first flush. Comparatively higher culturable bacterial population and bacterial PLFAs were found in the casing soil at the primordia formation stage of the first flush. There was a significant increase in the ratio of fungal to bacterial PLFAs during mushroom growth. Multivariate analysis of PLFA data demonstrated that the mushroom cropping stage could considerably affect the microbial community structure of the casing soil. The bacterial population increased significantly from casing soil application to the primordia formation stage of the first flush. Casing soil application resulted in an increase in the ratio of gram-negative bacterial PLFAs to gram-positive bacterial PLFAs, suggesting that some gram-negative bacteria might play an important role in mushroom sporophore initiation.     

稻秸杆覆盖对小麦根围拮抗细菌组成和小麦纹枯病发生的影响

To assess the effect of rice straw mulching on changes of antagonistic bacteria and the incidence of wheat sharp eyespot, a multi-year field study was performed to compare unmulched plots and the plots mulched with rice straw for two or three years. Bacterial and fungal populations were evaluated in the cultures prepared from the wheat rhizosphere and bulk soils. Rice straw mulching increased the number of pseudomonas colony forming units in wheat rhizosphere and bulk soils. The proportion of total bacteria that were fluorescent pseudomonads was higher in mulched than in unmulched soil. Bacterial isolates antagonistic to Rhizoctonia cerealis were identified using an inhibition zone test. A series of these isolates were typed by partial sequencing of the 16S rRNA gene. Pseudomonads had higher antagonistic activity against R. cerealis than other species, and more than 80% of rhizosphere fluorescent pseudomonads were antagonistic to R. cerealis. The disease indices were lower in the mulched plots than in the unmulched control. These results suggest that rice straw mulching in a rice-wheat rotation increases the number of fluorescent pseudomonads. Additionally, these fluorescent pseudomonads may contribute to the control of wheat sharp eyespot.     

对比景观土壤性质普通克里格法和回归克里格法的比较研究

The accuracy between ordinary kriging and regression kriging was compared based on the combined consideration of sample size, spatial structure, and auxiliary variables (terrain indices and electromagnetic induction surveys) for a variety of soil properties in two contrasting landscapes (agricultural vs. forested). When spatial structure could not be well captured by point-based observations (e. g., when the ratio of sample spacing over correlation range was > 0.5), or when a strong relationship existed between target soil properties and auxiliary variables (e. g., their R² was > 0.6), regression kriging (RK) was more accurate for interpolating soil properties in both landscapes studied. Otherwise, ordinary kriging (OK) was better. Soil depth and wetness condition did not appear to affect the selection of kriging for soil moisture interpolation, because they did not significantly change the ratio of sample spacing over correlation range and the relationship with the auxiliary variables. Because of a smaller ratio of elevation change over total study area (E/A = 1.2) and multiple parent materials in the agricultural land, OK was generally more accurate in that landscape. In contrast, a larger E/A ratio of 6.8 and a single parent material led to RK being preferable in the steep-sloped forested catchment. The results from this study can be useful for selecting kriging for various soil properties and landscapes.     

有机肥对磷的吸附-解吸的影响及在红壤发育成的水稻土上的有效性

A field test with the traditional rotation of paddy rice/upland crop (wheat) was carried out on a paddy soil derived from red earth to elucidate the effect of organic manure on the phosphorus adsorption-desorption by soil and its P availability. Soil samples were taken from different treatments at rice harvesting stage and analysed. The isothermal adsorption of P by the samples fitted very well with Langmuir equation, and hence, the parameters in the equation, i.e., maximum adsorption (qm), constant related to bonding energy (k) and their product (k × qm) could be used as a comprehensive index to characterize the potential P adsorptivity of the soil. Organo-inorganic fertilization and organic manuring could decrease qm and k, while mineral P application had little effect on them. The isothermal desorption of P was significantly correlated with initially added and isothermally adsorbed P. Part of P added was fixed, which represented the P fixation capacity of soil, and organic manuring could obviously lower the P fixation. The content of soil available P had a significant negative correlation with qm, k and fixed P. It is concluded that organic manure could increase the P availability of paddy soil derived from red earth by decreasing qm, k, maximum buffering capacity (MBC=k × qm) and fixation capacity.     

Relationship between granitic soil particle-size distribution and shrinkage properties based on multifractal method

The mechanical properties of granitic residual soils vary with depth due to changes in soil type and heterogeneity caused by weathering. The purpose of this study was to relate the spatial variation of particle-size distribution (PSD) of granitic soils with soil shrinkage parameters using multifractal theory. The heterogeneity of PSD and pedogenic processes were depicted in detail by multifractal dimensions. The PSD generally increased with the increase of profile depth in accordance with the variation of single fractal dimension (D) ranging from 2.45 to 2.65. The shrinkage limit was greatly influenced by the multifractal dimension parameters, including information dimension (D₁) and capacity dimension (D₀) (Adjusted R²=0.998, P < 0.01), and the maximum linear extensibility (κ_v) was determined by spectral width (△α) and bulk density, with the latter explaining 89% of the total variance of κ_v (P < 0.01). Soil shrinkage characteristic curve was fitted by the modified logistic model (R² > 0.97, root sum of squares < 0.1), and the water variation corresponding to the maximum change rate of linear extensibility was determined by the silt content (R²=0.81, P < 0.01). Overall, the shrinkage of granitic soils was primarily influenced by PSD and soil compactness.     

油蒿群落土壤碳酸钙和脱氢酶对土壤有机质的响应

Little attention has been paid to the role of soil organic matter (OM) in the formation of pedogenic carbonate in desert soils. The relationships among soil OM, soil dehydrogenase activity (DHA), and soil CaCO₃ in a plant community dominated by Artemisia ordosica, located on the eastern boundary of Tengger Desert in the Alxa League, Inner Mongolia, China, were studied to understand whether OM was directly involved in the formation of pedogenic carbonate. The results showed that DHA and CaCO₃ positively correlated with OM content, and DHA, OM, and CaCO₃ were correlated with each other in their spatial distribution, indicating that abundant OM content contributed to the formation of CaCO₃. Therefore, the formation of pedogenic CaCO₃ was a biotic process in the plant community dominated by A. ordosica.     

不同施肥方式下土中有机氯农药的残留特征

Soil samples with three fertilization treatments (no fertilizer, corn straw and farm manure) collected from a Lou soil (Eum-orthic Anthrosol classfied using Chinese Soil Taxonomy) in northwestern China were analysed for residual levels and their characteristics of organochlorine pesticides (α-HCH, β-HCH, γ-HCH, δ-HCH, HCB, o,p'-DDT, p,p'-DDT, o,p'-DDE, p,p'-DDE, p,p'-DDD, a-endosulfan, dieldrin and endrin). Organochlorine pesticides (OCPs) were detected in all soil samples except δ-HCH and their total concentrations ranged from 159.31 ± 9.00 to 179.77 ± 2.58 ng g^-1 with an order of HCHs > DDTs > (dieldrin + endrin) > HCB > α-endosulfan. Among all the compounds, γ-HCH had the highest concentration followed by p,p'-DDE. The residual levels of HCH isomers and DDT as well as their metabolites in soil with different fertilization treatments were in the order of γ-HCH > β-HCH ≈ α-HCH > δ-HCH and p,p'-DDE > p,p'-DDT > o,p'-DDT > p,p'-DDD ≈ o,p'-DDE, respectively. DDE/DDT ratios ranged from 1.59 ±0.13 to 3.35 ± 0.16 and endrin/dieldrin ratios from 1.40 ± 0.06 to 9.20 ± 4.05, both indicating no new occurrence of these pesticides in these soils, while α-HCH/γ-HCH ratios of 0.04 indicated a new input of lindane (almost pure γ-HCH) in the past several years. The farm manure treatments showed lower DDT residues than samples without fertilizer. Also addition of corn straw and farm manure increased soil organic matter content and decreased the soil pH which could retard the degradation of DDT in the soil.     

采用通气堆沤对石油烃污染土壤进行生物修复

Laboratory simulation studies and a composting pilot study were conducted to evaluate the capacity of three strains of fungi, indigenous fungus Fusarium sp. and Phanerochaete chrysosporium and Coriolus Versicolor, to remediate petroleum-contaminated soils. In laboratory, the fungi were inoculated into a liquidculture medium and the petroleum-contaminated soil samples for incubation of 40 and 50 days 5 respectively. In the 200-day pilot study, nutrient contents and moisture were adjusted and maintained under aerobiccondition in composting units using concrete container (118.5 cm × 65.5 cm × 12.5 cm) designed specially for this study. The laboratory simulation results showed that all the three fungi were effective in degrading petroleum in the liquid culture medium and in the soil. At the end of both the laboratory incubations, the degradation rates by Phanerochaete chrysosporium were the highest, reaching 66% after incubation in liquid culture for 50 days. This was further demonstrated in the composting pilot study where the degradation rate by P. chrysosporium reached 79% within 200 days, higher than those of the other two fungi (53.1% and 46.1%), indicating that P. chrysosporium was the best fungus for bioremediation of soil contaminated with petroleum. Further research is required to increase degradation rate.     

Biochemistry of TBT-Degrading Marine Pseudomonads Isolated from Indian Coastal Waters

Tributyltin (TBT) is a very effective biocide and an active ingredient in antifouling paints. Screening along the Indian coast yielded 49 bacterial isolates capable of TBT assimilation. The screening was done based on the ability of bacteria to grow in mineral salt medium (MSM) containing TBT as the sole source of carbon. All the isolates produced exopolysaccharides (biosurfactants) in the medium which aid in emulsification and thus ease bioavailability of TBT. Five isolates were identified as potent TBT degraders (namely, Pseudomonas pseudoalcaligenes, Pseudomonas stutzeri, Pseudomonas mendocina, Pseudomonas putida, and Pseudomonas balearica) based on their biomass production in MSM containing TBT as the sole source of carbon. In addition to evaluating the potential of individual bacterial strains, the study also focused on using a consortium of bacteria to explore their synergistic effect when grown on TBT. Further tests like growth profile, rhamnolipid secretion profile, extracellular protein secretion profile, and detection of siderophores were performed on these isolates when grown in MSM supplemented with 2 mM TBT concentration. Emulsification activity of the crude extracellular polysaccharides against kerosene was evaluated. It can be therefore inferred that TBT degradation by these marine pseudomonads is a two-step process: (a) dispersion of TBT in the aqueous phase and (b) tin–carbon bond cleavage by siderophores affecting debutylation of TBT. The consortium of bacteria may be effective in the treatment of TBT-contaminated waste water in dry docks.     

Potential of indigenous antagonistic rhizobacteria in the biological control of Monosporascus root rot and vine decline disease of muskmelon

ABSTRACT

Monosporascus root rot and vine decline (MRVD) of muskmelon, caused by Monosporascus cannonballus, is an economically important disease worldwide. The objectives of this study were to isolate native rhizobacterial strains and to evaluate their ability to promote plant growth and to provide protection against M. cannonballus. Thirty eight native bacterial isolates from the rhizosphere soil of muskmelon and cucumber were screened for their antagonism against M. cannonballus in a dual culture assay. Among them, five isolates viz., Bacillus amyloliquefaciens (B4), Pseudomonas mendocina (B7), Bacillus endophyticus (B10), Pseudomonas resinovorans B11 and P. aeruginosa AT3, identified based on the 16S rRNA gene sequence analysis, showed a significant level of antagonism and the inhibition zone ranged from 5.6 mm to 25.9 mm. Scanning electron microscopic observation of the hyphae of M. cannonballus at the inhibition zone revealed morphological abnormalities including shrinkage, loss of turgidity, pit formation and deformation. These bacterial isolates showed compatibility with one another and with Trichoderma viride. Greenhouse experiments revealed that P. resinovorans B11 was the most effective among the bacterial antagonists in controlling MRVD in melon. When applied as seed treatment and soil application, P. resinovorans B11 reduced the incidence of MRVD by 93.1%, relative to the infected control.     

Growth and nitrogenous excretion of a common soil flagellate Spumella sp.—a laboratory experiment

The growth and nitrogenous excretion of a common soil flagellate, Spumella sp., isolated from a Scottish podzol and fed with the common soil bacterium, Pseudomonas fluorescens, were investigated. Video-enhanced light microscopy and transmission electron microscopy were used to study the digestion process. Ingestion of the bacteria occurred rapidly at the base of the two flagella and involved the formation of a small protrusion, which surrounded the prey. The first signs of digestion appeared a few minutes after ingestion with the degradation of the outer membrane of the bacteria. Digestion was complete within 30–60 min, and the indigestible bacterial residues were then released into the medium. Ammonium nitrogen was the major form of nitrogen excreted. Some apparently intact P. fluorescens bacteria were also egested. For each division 130 bacteria were required. No feeding activities were observed at 5°C. Of the total bacterial protein, 42% was incorporated into biomass of flagellates.     

Effect of single and dual phosphate-solubilizing bacterial strain inoculations on overall growth of mung bean plants

Available phosphorus is limiting in most cultivable soils in several parts of India, including Rajasthan. Four phosphate-solubilizing bacterial strains viz. Pseudomonas fluorescens BAM-4, Burkholderia cepacia BAM-6, B. cepacia BAM-12 and Aeromonas vaga BAM-77 were isolated from the rhizosphere of pearl millet (Pennisetum glaucum, cv. Raj 171), mung bean (Phaseolus aureus, cv. RMG 492) and sesame (Sesamum indicum, cv. RT 46). To the best of our knowledge, this is the first report on phosphate solubilization by Aeromonas vaga. Seed inoculation of mung bean with or without tricalcium phosphate (TCP) was performed to study the effect of single and dual bacterial inoculations in pot trials having sterilized sandy loam soil, and was found to enhance the growth and yield of plants. The results were on a par with chemical fertilizer, single superphosphate (SSP) and commercial biofertilizers, PSB (Bacillus polymyxa) and MC (Pseudomonas striata), used as standard reference. Addition of TCP to soil gave better results and dual inoculation was more effective than single inoculation of bacteria. Among the four strains studied, A. vaga and P. fluorescens were found to be more valuable as single inoculants in terms of plant growth, whereas in combination treatments, P. fluorescens along with B. cepacia and A. vaga performed very well both in the presence and absence of TCP.     

Interspecific interactions in dual-species biofilms of soil bacteria: effects of fertilization practices

Purpose

Bacterial cooperation and competition in biofilms are being recognized as important factors in regulating structure and function of microbial communities. However, knowledge about soil bacterial interactions in biofilms and how these may be influenced by different fertilization practices is still limited. This study aims to investigate interspecific interactions in biofilms and the effects of fertilization practices on these interactions.

Materials and methods

We assessed bacterial interactions according to a classification criterion proposed recently via comparing biomass of single-species biofilms with dual-species biofilms. Biofilm biomass was measured by crystal violet staining using the modified Calgary biofilm device.

Results and discussion

Increased biofilm formation was detected in 67% of co-cultures that were composed of strains isolated from unfertilized soil, indicating a high prevalence of cooperation among the strains in natural soil. In contrast, decreased biofilm formation was detected in 74% of co-cultures that contained strains isolated from soil receiving chemical fertilizer. Interestingly, combinations of bacterial isolates from soils amended with chemical fertilizer in combination with composted chicken manure or mushroom residues showed higher level of synergism and biofilm induction in dual-species biofilms than the strains from chemically fertilized soils, suggesting integrated fertilization with composted chicken manure or mushroom residues may help maintain the native microbial interaction network dominated by synergistic interactions.

Conclusions

Together, these findings indicate that social interactions, required for biofilm formation, among soil bacteria are affected by fertilization practices. Cooperation is dominant in dual-species biofilms in unfertilized soil. Organic manure could mitigate the negative impacts on bacterial social interactions caused by chemical fertilizers.

     

Metabolic and physiological characteristics of salt-tolerant strains of Bradyrhizobium spp.

 Biochemical and physiological characteristics of salt-tolerant (88 mM, 264 mM and 440 mM NaCl) strains of Bradyrhizobium were evaluated according to their capacity for using different carbon sources, growth rate, resistance to antibiotics, plasmid profile and exopolysaccharide production. Salt-tolerant strains significantly enhance their capacity to oxidize C sources (about 75–85 compounds) by increasing growth rate and exopolysaccharide production involved in adhesion, resulting in a greater adapting capacity to colonize unfavorable saline environments. However, salt stress could work as a curing agent and thus the gene stability would become critical for the biological nitrogen-fixation information present in plasmids, as is the case in Rhizobium. Received: 5 January 1998     

Effect of passage through the intestinal tract of detritivore earthworms (Lumbricus spp.) on the number of selected Gram-negative and total bacteria

Laboratory experiments were carried out to investigate the fate of bacteria during and after passage through the intestinal tract of detritivore earthworms. Earthworms (Lumbricus spp.) were fed with cattle dung inoculated 7 days previously with one of five different Gram-negative bacteria. Bacterial concentrations were determined 2 days later in dung and soil, and in gut material from different parts of the earthworm intestinal tract. A high percentage (28–82%) of the total bacteria (epifluorescence direct counts) in the earthworm gut content was culturable. The concentration of total heterotrophic aerobic bacteria did not vary significantly among the five different bacterial additions and the non-inoculated control. In earthworm casts the number of total heterotrophs per gram dry matter (2.1×10⁹) was higher than in soil (1.7×10⁸), but lower than in the dung (1.5×10¹⁰). The test-bacteria, however, showed different survival patterns along the earthworm intestinal tract. The concentrations of Escherichia coli BJ 18 and Pseudomonas putida MM 1 and MM 11 in earthworm casts were lower than in the ingested dung, while concentrations of Enterobacter cloacae A 107 and Aeromonas hydrophila DMU 115 in dung and casts were similar. Ent. cloacae, and to aminor extent E. coli, were reduced in numbers by several orders of magnitude in the pharynx and/or crop. In the hind gut, however, the concentration of Ent. cloacae had increased to the same level as in the ingested dung, while the concentration of E. coli remained low. Our observations indicate that the bacterial flora of ingested food materials changes qualitatively and quantitatively during gut transit.     

Colonization of torrefied grass fibers by plant-beneficial microorganisms

This study aimed to assess the colonization of thermally treated (i.e. torrefied) grass fibers (TGFs), a new prospective ingredient of potting soil. Eleven bacterial strains and one fungus, Coniochaeta ligniaria F/TGF15, all isolated from TGF or its extract after inoculation with a soil microbial community, were tested for their ability to colonize TGF. Surprisingly, none of these bacteria were able to directly colonize TGF either as single inoculants or as a consortium. Furthermore, bacterial persistence or growth in TGF was not improved by the addition of nutrients or a surfactant. Only extensive washing of the substrate, presumably removing bacteriostatic or bactericidal compounds, allowed bacterial growth on the fibers. Strikingly, the fungal strain consistently colonized TGF up to high densities (up to 10¹⁰ CFU per g dry TGF). Given the unique capacity of this fungus to degrade toxic compounds including phenols, TGF was colonized with it for different periods of time, after which a consortium of seven selected bacterial isolates was added. Co-presence of the fungus, or 3 and 24 h pre-colonization with it, was insufficient to create a habitable environment for the bacterial consortium. However, fungal pre-colonization of minimally 3 days allowed the bacterial consortium to colonize the TGF at numbers up to 10⁹ to 10¹⁰ CFU per g dry substrate. The resultant bacterial community consisted of at least four strains, i.e. Pseudomonas putida 15/TGE5, Serratia plymuthica 23/TGE5, Pseudomonas corrugata 31/TGE5, and Methylobacterium radiotolerans 56/TGF10, as shown by PCR of colonies on plates and PCR–DGGE profiling. Two persisters, S. plymuthica 23/TGE5 and P. corrugata 31/TGE5, were highly antagonistic towards several phytopathogenic fungi. Thus, a microbial community with plant-beneficial potential was established on TGF, provided that the fungus C. ligniaria F/TGF15 first creates habitable space in the matrix.     

Effect of co-inoculation of plant growth-promoting rhizobacteria on the growth of amaranth plants

This study shows the effect of co-inoculation of three bacterial isolates, viz. Bacillus firmus KUCr1, Cellulosimicrobium cellulans KUCr3 and Pseudomonas aeruginosa KUCd1, on selected growth parameters of amaranth plants. KUCr1 and KUCr3 are reported to be P-solubilizers and indole acetic acid (IAA) producers, and KUCd1 is a siderophore producer. Co-inoculation of the three isolates gave the best results for overall growth of amaranth plants followed by co-inoculation with KUCr1 and KUCd1, then KUCr1 alone. Among the test isolates, KUCr1 and KUCd1 were found to be better rhizosphere colonizers when co-inoculated. KUCr1 and KUCr3 when co-inoculated produced more IAA in liquid medium. Co-inoculation gave insignificant variation in P-solubilization, but siderophore production by KUCd1 was greatly enhanced when inoculated with other isolates in culture conditions. The augmentation of plant growth, whenusing a consortium culture, might be due to better IAA production andsiderophore production by the test isolates. This report suggests that co-inoculation of microbes promotes plant growth better than individual isolates.     

Isolation and characterisation of phages against Pseudomonas syringae pv. actinidiae

Purpose: Pseudomonas syringae pv. actinidiae causes bacterial canker of kiwifruit and is responsible for severe economic losses and emergence of drug-resistant bacteria. Bacteriophages are viruses that infect target bacterial hosts and may be the best strategy to prevent and control kiwifruit canker disease. The objective of this experiment was to monitor the prevalence of Pseudomonas syringae pv. actinidiae and provide insight for the use of phages in biological control.

Materials and methods: In this study, 52 strains of Pseudomonas syringae pv. actinidiae were isolated from 68 stem samples of kiwi plant (cv. Hongyang & Jinkui). Following polymerase chain reaction (PCR) analysis, 15 isolates belonging to biovar 3 were identified, one of which was named XWY0007 and used as the target strain to isolate the phages. Thirty-six phages were isolated and purified from a total of 51 surface water samples collected in Shanghai. All phages were identified by transmission electron microscopy (TEM) and their host ranges were evaluated. Three phages, designated φXWY0013, φXWY0014 and φXWY0026 were selected and further characterised using one-step growth curve and stability at different temperatures and pH.

Results and conclusions: The isolated phages are promising for use as antimicrobials against bacterial canker in kiwi. This report is regarding Pseudomonas syringae pv. actinidiae and its phages from major areas of kiwifruit cultivation.