Survival of Teliospores of Tilletia indica in Arizona Field Soils

The survival of teliospores of the Karnal bunt of wheat pathogen, Tilletia indica, was determined in field plots in Tucson, AZ. Two methods were used to test viability during a 48-month period in which 21-μm-pore-size polyester mesh bags of teliospore-infested soil were buried in irrigated and nonirrigated field plots at two sites. One method determined the total number of viable teliospores in a soil sample, regardless of whether or not they could be extracted from the soil using a sucrose centrifugation technique. The total number of viable teliospores declined over time in both irrigated and nonirrigated field plots and in the same soils in the laboratory. Based on nonlinear regressions, total number of viable teliospores decreased from 55.7% at time zero to 9.7 and 6.7% for nonirrigated and irrigated field soils, respectively, in 48 months. Total number of viable teliospores in soil in the laboratory decreased from 55.7 to 34.0% after 48 months. The second method determined germination percentages of teliospores extracted from the soil samples by means of a sucrose centrifugation technique. Based on linear regressions of transformed data, germination of teliospores extracted from irrigated and nonirrigated field soils, and control (laboratory) soil, significantly decreased over time. The rate of decrease in germination was significantly greater for teliospores from irrigated field plots than from nonirrigated plots and the laboratory soil. At time zero, 55.7% of teliospores germinated, and by 48 months, average germination of teliospores extracted from soil in nonirrigated plots had decreased to 13.6% compared with 4.4% in irrigated plots and 36.8% for teliospores in the laboratory control. Regression over time of total number of viable teliospores accounted for more of the overall variability than did regression over time of germination percentages of extracted teliospores. Neither field site nor soil depth had any effect on total number of viable teliospores or on teliospore germination percentages.

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Comparison of Effects of Acidic Electrolyzed Water and NaOCl on Tilletia indica Teliospore Germination

Plant Disease ◽

10.1094/pdis.1999.83.7.627 ◽

1999 ◽

Vol 83 (7) ◽

pp. 627-632 ◽

Cited By ~ 35

Author(s):

M. R. Bonde ◽

S. E. Nester ◽

A. Khayat ◽

J. L. Smilanick ◽

R. D. Frederick ◽

...

Keyword(s):

Pcr Amplification ◽

Alternative Methods ◽

Karnal Bunt ◽

Tilletia Indica ◽

Chain Reaction ◽

Direct Pcr ◽

Electrolyzed Water ◽

Teliospore Germination ◽

Polymerase Chain ◽

Axenic Cultures

Definitive identification of free teliospores of Tilletia indica, causal agent of Karnal bunt of wheat, requires polymerase chain reaction (PCR)-based diagnostic tests. Since direct PCR amplification from teliospores has not been reliable, teliospores first must be germinated in order to obtain adequate DNA. We have routinely surface-sterilized teliospores for 2 min with 0.4% (vol/vol) sodium hypochlorite (NaOCl) to stimulate germination and produce axenic cultures. However, we observed that some spores were killed even with a 2-min NaOCl treatment, the shortest feasible duration. Decreasing the NaOCl concentration in our study from 0.4% to 0.3 and 0.2%, respectively, increased teliospore germination, but treatment times longer than 2 min still progressively reduced the germination percentages. In testing alternative methods, we found “acidic electrolyzed water” (AEW), generated by electrolysis of a weak solution of sodium chloride, also surface-sterilized and increased the rate of T. indica teliospore germination. In a representative experiment comparing the two methods, NaOCl (0.4%) for 2 min and AEW for 30 min increased germination from 19% (control) to 41 and 54%, respectively, by 7 days after treatment. Because teliospores can be treated with AEW for up to 2 h with little, if any, loss of viability, compared with 1 to 2 min for NaOCl, treatment with AEW has certain advantages over NaOCl for surface sterilizing and increasing germination of teliospores of suspect T. indica.

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Survival of Tilletia indica Teliospores in Different Soils

Plant Disease ◽

10.1094/pdis.2004.88.4.316 ◽

2004 ◽

Vol 88 (4) ◽

pp. 316-324 ◽

Cited By ~ 17

Author(s):

M. R. Bonde ◽

D. K. Berner ◽

S. E. Nester ◽

G. L. Peterson ◽

M. W. Olsen ◽

...

Keyword(s):

Polyvinyl Chloride ◽

Karnal Bunt ◽

Infested Soil ◽

Tilletia Indica ◽

Polyester Mesh ◽

Mesh Bags ◽

Dry Soil ◽

Different Soils

To determine the potential for Tilletia indica, cause of Karnal bunt of wheat, to survive and become established in new areas, a teliospore longevity study was initiated in Kansas, Maryland, Georgia, and Arizona. Soil from each location was infested with T. indica teliospores and placed in polyester mesh bags. The bags were placed within soil from the same location within polyvinyl chloride pipes. Pipes were buried in the respective plots such that the bags were at 5-, 10-, and 25-cm depths. Each pipe was open at the ends to allow interaction with the outside environment, however fitted with screens preventing possibility of teliospore escape. In the Karnal bunt-quarantine area of Arizona, bags of infested soil also were placed outside the pipes. Teliospore-infested soil from each location was maintained dry in a laboratory. During the first 2 years, viability declined more rapidly in pipes than outside pipes, and more rapidly in fields in Kansas and Maryland than in Georgia or Arizona. After 2 years, viability declined nearly equally. In the laboratory over 3 years, viability decreased significantly more rapidly in dry soil from Kansas or Maryland than in dry soil from Georgia or Arizona, while pure teliospores remained unchanged. We hypothesized that soils, irrespective of weather, affect teliospore longevity

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Survival of Teliospores of Tilletia indica in Soil

Plant Disease ◽

10.1094/pdis.2004.88.1.56 ◽

2004 ◽

Vol 88 (1) ◽

pp. 56-62 ◽

Cited By ~ 21

Author(s):

M. Babadoost ◽

D. E. Mathre ◽

R. H. Johnston ◽

M. R. Bonde

Keyword(s):

Soil Samples ◽

Infested Soil ◽

Silty Clay ◽

Tilletia Indica ◽

Teliospore Germination ◽

Different Temperatures ◽

Loam Soil ◽

The Mean ◽

Northern United States ◽

Depth Of Burial

This study was conducted to assess survival of Tilletia indica teliospores in a location in the northern United States. Soils differing in texture and other characteristics were collected from four locations, equilibrated to -0.3 MPa, and infested with teliospores of T. indica to give a density of 103 teliospores per gram of dry soil. Samples (22 g) of the infested soil were placed in 20-μm mesh polyester bags, which were sealed and placed at 2-, 10-, and 25-cm depths in polyvinyl chloride tubes containing the same field soil as the infested bags. Tubes were buried vertically in the ground at Bozeman, MT, in October 1997. Soil samples were assayed for recovery and germination of T. indica teliospores 1 day and 8, 20, and 32 months after incorporation of teliospores into soil. The rates of teliospores recovered from soil samples were 90.2, 18.7, 16.1, and 13.3% after 1 day and 8, 20, and 32 months after incorporation of teliospores into soil, respectively, and was significantly (P < 0.01) affected by soil source. The percentage of teliospore recovery from soil was the greatest in loam soil and lowest from a silt loam soil. The rate of teliospores recovered from soil was not significantly affected by depth of burial and the soil source-depth interaction during the 32-month period. The percentage of germination of teliospores was significantly (P < 0.01) affected by soil source and depth of burial over the 32-month period. The mean percentage of teliospore germination at 1 day, and 8, 20, and 32 months after incorporation into soils was 51.3, 15.1, 16.4, and 16.5%, respectively. In another experiment, samples of silty clay loam soil with 5 × 103 teliospores of T. indica per gram of soil were stored at different temperatures in the laboratory. After 37 months of incubation at 22, 4, -5, and -18°C, the rates of teliospore recovered from soil were 1.6, 2.0, 5.7, and 11.3%, respectively. The percentage of spore germination from soil samples was highest at -5°C. Microscopy studies revealed that disintegration of teliospores begin after breakdown of the sheath-covering teliospore. The results of this study showed that teliospores of T. indica can survive in Montana for more than 32 months and remain viable.

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Improved Detection of Tilletia indica Teliospores in Seed or Soil by Elimination of Contaminating Microorganisms with Acidic Electrolyzed Water

Plant Disease ◽

10.1094/pdis.2003.87.6.712 ◽

2003 ◽

Vol 87 (6) ◽

pp. 712-718 ◽

Cited By ~ 5

Author(s):

M. R. Bonde ◽

S. E. Nester ◽

N. W. Schaad ◽

R. D. Frederick ◽

D. G. Luster

Keyword(s):

Karnal Bunt ◽

Wheat Seed ◽

Tilletia Indica ◽

Soil Extracts ◽

Electrolyzed Water ◽

Teliospore Germination ◽

Oxidation Reduction ◽

Oxidation Reduction Potential ◽

Pure Cultures ◽

Bacteria And Fungi

Acidic electrolyzed water (AEW) is a germicidal product of electrolysis of a dilute solution (e.g., 0.4% vol/vol) of sodium chloride. This solution can be used to disinfest wheat seed or soil samples being tested for teliospores of Tilletia indica, causal agent of Karnal bunt, without risk of damaging the teliospores. The AEW used in this study had a pH of 2.5 to 2.8 and oxidation-reduction potential of approximately 1,130 mV. In simulations of routine extractions of wheat seed to detect teliospores of T. indica, the effectiveness of a 30-min AEW treatment was compared with a 2-min 0.4% sodium hypochlorite (NaOCl) treatment to eradicate bacteria and nonsmut fungi. Each treatment reduced bacterial and fungal populations in wheat seed extracts by 6 to 7 log10 units when determined on 2% water agar with antibiotics. Reductions of 5 log10 units or more were observed on other media. NaOCl and AEW also were very effective at eliminating bacteria and fungi from soil extracts. In studies to detect and quantitate T. indica teliospores in soil, AEW was nearly 100% effective at eliminating all nonsmut organisms. Free chlorine levels in AEW were very low, suggesting that compounds other than those with chlorine play a significant role in sanitation by AEW. The low pH of AEW was shown to contribute substantially to the effectiveness of AEW to reduce microorganisms. A standardized protocol is described for a 30-min AEW treatment of wheat seed washes or soil extracts to eliminate contaminating microorganisms. A significant advantage of the use of AEW over NaOCl is that, with AEW, teliospore germination is not reduced and usually is stimulated, whereas teliospore germination declines after contact with NaOCl. The protocol facilitates detection and enumeration of viable teliospores of T. indica in wheat seed or soil and the isolation of pure cultures for identification by polymerase chain reaction. The germicidal effects of AEW, as demonstrated in this study, illustrate the potential of AEW as an alternative to presently used seed disinfestants.

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Induction of MAP Kinase Homologues during Growth and Morphogenetic Development of Karnal Bunt (Tilletia indica) under the Influence of Host Factor(s) from Wheat Spikes

The Scientific World JOURNAL ◽

10.1100/2012/539583 ◽

2012 ◽

Vol 2012 ◽

pp. 1-12 ◽

Cited By ~ 2

Author(s):

Atul K. Gupta ◽

J. M. Seneviratne ◽

G. K. Joshi ◽

Anil Kumar

Keyword(s):

Map Kinase ◽

Map Kinases ◽

Fungal Growth ◽

Host Factor ◽

Host Factors ◽

Karnal Bunt ◽

Dependent Manner ◽

Tilletia Indica ◽

Mitogen Activated Protein

Signaling pathways that activate different mitogen-activated protein kinases (MAPKs) in response to certain environmental conditions, play important role in mating type switching (Fus3) and pathogenicity (Pmk1) in many fungi. In order to determine the roles of such regulatory genes inTilletia indica, the causal pathogen of Karnal bunt (KB) of wheat, semi-quantitative and quantitative RT-PCR was carried out to isolate and determine the expression of MAP kinase homologues during fungal growth and development underin vitroculture. Maximum expression of TiFus3 and TiPmk1 genes were observed at 14th and 21st days of culture and decreased thereafter. To investigate whether the fungus alters the expression levels of same kinases upon interaction with plants, cultures were treated with 1% of host factors (extracted from S-2 stage of wheat spikes). Such treatment induced the expression of MAPks in time dependent manner compared to the absence of host factors. These results suggest that host factor(s) provide certain signal(s) which activate TiFus3 and TiPmk1 during morphogenetic development ofT. indica. The results also provides a clue about the role of host factors in enhancing the disease potential due to induction of MAP kinases involved in fungal development and pathogenecity.

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Incidence and Survival of Cylindrocladium parasiticum in Peanut Seed

Plant Disease ◽

10.1094/pdis.2003.87.7.867 ◽

2003 ◽

Vol 87 (7) ◽

pp. 867-871 ◽

Cited By ~ 7

Author(s):

D. L. Glenn ◽

P. M. Phipps ◽

R. J. Stipes

Keyword(s):

Seed Storage ◽

Infested Soil ◽

Ambient Temperatures ◽

Growing Seasons ◽

Commercial Seed ◽

Cylindrocladium Parasiticum ◽

High Incidence ◽

Normal Seed ◽

Pathogen Recovery ◽

Field Plots

Sixty-three commercial seed lots of peanut produced in Virginia were examined for the presence of seed with speckled testae. Speckled seed were present in seed lots from the 1998, 1999, and 2000 growing seasons at average rates of 3, 1.2, and 0.6%, respectively. Speckled and normal seed from 19 seed lots were assayed on a medium selective for C. parasiticum. The fungus was isolated from speckled seed at rates ranging from 40 to 96%. C. parasiticum was isolated only from a single normal seed from one seed lot. The pathogen was recovered at high rates from speckled seed immediately after pods had been dried in commercial drying trailers at temperatures up to 35°C. Ambient temperatures during winter seed storage that fluctuated from -10 to 28°C in 1999 and -8 to 33°C in 2000 greatly reduced pathogen recovery in speckled seed stored for 16 or 24 weeks. In field plots with naturally infested soil, the number of speckled seed harvested was directly correlated to the number of symptomatic plants in plots on 29 September. Based on this finding, the harvest of seed peanuts in areas of a field with high incidence of Cylindrocladium black rot (CBR) should be avoided. Adoption of this policy is expected to lower the number of speckled seed entering commercial seed lots and reduce the risk for spread of CBR.

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Effect of biofumigation with volatiles from Muscodor albus on the viability of Tilletia spp. teliospores

Canadian Journal of Microbiology ◽

10.1139/w08-104 ◽

2009 ◽

Vol 55 (2) ◽

pp. 203-206 ◽

Cited By ~ 21

Author(s):

Blair J. Goates ◽

Julien Mercier

Keyword(s):

Organic Compounds ◽

Seedling Emergence ◽

Karnal Bunt ◽

Smut Fungi ◽

Tilletia Indica ◽

Common Bunt ◽

Volatile Organic ◽

Petri Dishes ◽

Postharvest Control ◽

Muscodor Albus

Volatile organic compounds produced by the fungus Muscodor albus inhibit or kill numerous fungi. The effect of these volatiles was tested on dormant and physiologically active teliospores of the smut fungi Tilletia horrida , Tilletia indica , and Tilletia tritici , which cause kernel smut of rice, Karnal bunt of wheat, and common bunt of wheat, respectively. Reactivated rye grain culture of M. albus was used to fumigate dormant teliospores in dry Petri dishes and physiologically active teliospores on water agar for up to 5 days at 22 °C. Teliospores of all 3 species were incapable of germination when fumigated on agar for 5 days. When T. tritici on agar was fumigated only during the initial 48 h of incubation, viability was reduced by 73%–99%. Fumigation of dry loose teliospores of T. tritici caused a 69%–97% loss in viability, whereas teliospores within intact sori were not affected. Dormant teliospores of T. horrida and T. indica were not affected by M. albus volatiles. It appears that M. albus has potential as a seed or soil treatment for controlling seedling-infecting smuts where infection is initiated by germinating teliospores prior to seedling emergence. The volatiles were not effective for postharvest control of teliospores under conditions used in these experiments.

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Centenary of Soil and Air Borne Wheat Karnal Bunt Disease Research: A Review

Biology ◽

10.3390/biology10111152 ◽

2021 ◽

Vol 10 (11) ◽

pp. 1152

Author(s):

Mir Asif Iquebal ◽

Pallavi Mishra ◽

Ranjeet Maurya ◽

Sarika Jaiswal ◽

Anil Rai ◽

...

Keyword(s):

Agronomic Traits ◽

Association Studies ◽

Farmyard Manure ◽

Wheat Breeding ◽

Karnal Bunt ◽

Farm Income ◽

Resistance Locus ◽

Genome Wide Association Studies ◽

Tilletia Indica ◽

Causal Pathogen

Karnal bunt (KB) of wheat (Triticum aestivum L.), known as partial bunt has its origin in Karnal, India and is caused by Tilletia indica (Ti). Its incidence had grown drastically since late 1960s from northwestern India to northern India in early 1970s. It is a seed, air and soil borne pathogen mainly affecting common wheat, durum wheat, triticale and other related species. The seeds become inedible, inviable and infertile with the precedence of trimethylamine secreted by teliospores in the infected seeds. Initially the causal pathogen was named Tilletia indica but was later renamed Neovossia indica. The black powdered smelly spores remain viable for years in soil, wheat straw and farmyard manure as primary sources of inoculum. The losses reported were as high as 40% in India and also the cumulative reduction of national farm income in USA was USD 5.3 billion due to KB. The present review utilizes information from literature of the past 100 years, since 1909, to provide a comprehensive and updated understanding of KB, its causal pathogen, biology, epidemiology, pathogenesis, etc. Next generation sequencing (NGS) is gaining popularity in revolutionizing KB genomics for understanding and improving agronomic traits like yield, disease tolerance and disease resistance. Genetic resistance is the best way to manage KB, which may be achieved through detection of genes/quantitative trait loci (QTLs). The genome-wide association studies can be applied to reveal the association mapping panel for understanding and obtaining the KB resistance locus on the wheat genome, which can be crossed with elite wheat cultivars globally for a diverse wheat breeding program. The review discusses the current NGS-based genomic studies, assembly, annotations, resistant QTLs, GWAS, technology landscape of diagnostics and management of KB. The compiled exhaustive information can be beneficial to the wheat breeders for better understanding of incidence of disease in endeavor of quality production of the crop.

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Microbial Utilisation of Aboveground Litter-Derived Organic Carbon Within a Sandy Dystric Cambisol Profile

Frontiers in Soil Science ◽

10.3389/fsoil.2021.666950 ◽

2021 ◽

Vol 1 ◽

Author(s):

Sebastian Preusser ◽

Patrick Liebmann ◽

Andres Stucke ◽

Johannes Wirsching ◽

Karolin Müller ◽

...

Keyword(s):

Microbial Biomass ◽

Organic Carbon ◽

Soil Depth ◽

Sampling Period ◽

Beech Forest ◽

Stable Isotope Labelling ◽

C Stocks ◽

Microbial Groups ◽

Aboveground Litter ◽

Over Time

Litter-derived dissolved organic carbon (DOC) is considered to be a major source of stabilised C in soil. Here we investigated the microbial utilisation of litter-derived DOC within an entire soil profile using a stable isotope labelling experiment in a temperate beech forest. The natural litter layer of a Dystric Cambisol was replaced by 13C enriched litter within three areas of each 6.57 m−2 for 22 months and then replaced again by natural litter (switching-off the 13C input). Samples were taken continuously from 0 to 180 cm depths directly after the replacement of the labelled litter, and 6 and 18 months thereafter. We followed the pulse of 13C derived from aboveground litter into soil microorganisms through depth and over time by analysing 13C incorporation into microbial biomass and phospholipid fatty acids. Throughout the sampling period, most of the litter-derived microbial C was found in the top cm of the profile and only minor quantities were translocated to deeper soil. The microbial 13C stocks below 30 cm soil depth at the different samplings accounted constantly for only 6–12% of the respective microbial 13C stocks of the entire profile. The peak in proportional enrichment of 13C in subsoil microorganisms moved from upper (≤ 80 cm soil depth) to lower subsoil (80–160 cm soil depth) within a period of 6 months after switch-off, and nearly disappeared in microbial biomass after 18 months (< 1%), indicating little long-term utilisation of litter-derived C by subsoil microorganisms. Among the different microbial groups, a higher maximum proportion of litter-derived C was found in fungi (up to 6%) than in bacteria (2%), indicating greater fungal than bacterial dependency on litter-derived C in subsoil. However, in contrast to topsoil, fungi in subsoil had only a temporarily restricted increase in litter C incorporation, while in the Gram-positive bacteria, the C incorporation in subsoil raised moderately over time increasingly contributing to the group-specific C stock of the entire profile (up to 9%). Overall, this study demonstrated that microorganisms in topsoil of a Dystric Cambisol process most of the recently deposited aboveground litter C, while microbial litter-derived C assimilation in subsoil is low.

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Nitrogen losses from grazed dairy pasture, as affected by nitrogen fertiliser application

Proceedings of the New Zealand Grassland Association ◽

10.33584/jnzg.1995.57.2175 ◽

1995 ◽

pp. 21-25

Author(s):

S.F. Ledgard ◽

D.A. Clark ◽

M.S. Sprosen ◽

G.J. Brier ◽

E.K.K. Nemaia

Keyword(s):

Soil Depth ◽

Major Effect ◽

N Fixation ◽

Ammonia Loss ◽

N Losses ◽

Nitrogen Fertiliser ◽

Nitrate N ◽

N Treatment ◽

Fertiliser Application ◽

Over Time

Abstract Inputs and losses of nitrogen (N) were determined in dairy farmlets receiving nominally 0, 200 or 400 kg N/ha/yr as urea at Dairying Research Corporation No. 2 dairy, Hamilton. In year 1, N, fixation by white clover was estimated by r5N dilution at 212, 165 and 74 kg N/ha/yr in the 0, 200 and 400 N treatments respectively. Removal of N in milk was 76, 89 and 92 kg N/ha in the 0, 200 and 400 N farmlets respectively. Loss of N into the air by denitrification was low (6-15 kg N/ha/yr), and increased with N application. Ammonia loss into the air was estimated by micrometeorological mass balance at 15, 45 and 63 kg Nlhalyr in the 0, 200 and 400 N treatments respectively. Most of the increase in ammonia loss was attributed to direct loss after fertiliser application. Leaching of nitrate was estimated using ceramic cup samplers at 1 m soil depth, in conjunction with lysimeters, to be 74, 101 and 204 kg NlhaJyr during the second winter when rainfall and drainage (55@-620 mm) were relatively high. Nitrate-N concentrations in leachates increased gradually over time in the 400 N treatment to an average of 37 mg/l during the second winter, whereas the corresponding values for the 0 and 200 N treatments were 12 and 18 mg/l. Preliminary measurements of groundwater suggest that :ihe nitrate-N concentration is increasing under the 400 N farmlet relative to the other two farmlets. Thus, the 400 N treatment had a major effect by greatly reducing N, fixation and increasing N losses, whereas the 200 N treatment had relatively little effect on N, fixation or on nitrate leaching. However, these results refer to the first 18 months of the trial and further measurements are required over time to determine the longer-term effects of these treatments, particularly on nitrate levels in groundwater. Keywords: ammonia loss, dairying, denitrification, groundwater, leaching, nitrogen fertiliser, N, fixation

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