Progress 06/21/11 to 09/30/13
Outputs
Target Audience: Scientific community, especially soil microbiologists, plant pathologists, and plant breeders Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest? Published in scientific journal What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Analysis was continued on results from laboratory studies to determine the impact of oilseed meals on soil microbial communities. In the first study, soil microbial community responses to amendments of a glucosinolate-containing brassicaceous oilseed meal (Brassica juncea, mustard), a non-glucosinolate-containing, nonbrassicaceous oilseed meal (Linum usitatissimum, flax), and a nonoilseed biomass (Sorghum bicolor, sorghum-sudangrass) were characterized using a 28-day time series of replicated 16S rRNA gene and fungal ITS gene sequence libraries. The results from this study were published in 2013. In the second study, the effects of four types of isothiocyanates (ITCs), including allyl, butyl, phenyl, and benzyl ITC, on soil fungal and bacterial communities were determined. Each ITC was added to soil that also received 1% flax seedmeal (to represent organic material added by seedmeals). Microbial communities were analyzed based on the ITS gene for fungi and16S rRNA gene for bacteria using qPCR and tag-pyrosequencing with 454 GS FLX titanium technology. A manuscript based on these results was submitted for publication and is currently being revised based upon reviewer comments. In the first study, distinct separation occurred by amendment type, with mustard inducing large increases in the abundance of bacterial taxa associated with fungal disease suppression (e.g. Bacillus, Pseudomonas, and Streptomyces spp.). Dramatic shifts were seen among the fungi, too, with phylotype richness decreasing by > 60% following mustard addition. Changes in bacterial and fungal community composition were rapid, and distinct community types persisted throughout the study. In the second study, a dramatic decrease in fungal populations (~85% reduction) was observed after allyl ITC addition. Fungal community compositions also shifted following ITC amendments (e.g., Humicola increased in allyl and Mortierella in butyl ITC amendments). Bacterial populations were less impacted by ITCs with community compositions being primarily impacted by time of incubation. Our results indicate that the type of ITC released from seedmeals may result in differential impacts on soil microorganisms. This information will likely impact the selection and breeding of plants for biofumigation-based control of soil-borne pathogens while minimizing the impacts on non-target microorganisms.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Hollister, E.B., P. Hu, A.S. Wang, F.M. Hons, and T.J. Gentry. 2013. Differential impacts of brassicaceous and non-brassicaceous oilseed meals on soil bacterial and fungal communities. FEMS Microbiol. Ecol. 83:632-641.
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Progress 01/01/13 to 09/30/13
Outputs
Target Audience: Scientific community, especially soil microbiologists, plant pathologists, and plant breeders Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest? Results published in scientific journal What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Analysis was continued on results from laboratory studies to determine the impact of oilseed meals on soil microbial communities. In the first study, soil microbial community responses to amendments of a glucosinolate-containing brassicaceous oilseed meal (Brassica juncea, mustard), a non-glucosinolate-containing, nonbrassicaceous oilseed meal (Linum usitatissimum, flax), and a nonoilseed biomass (Sorghum bicolor, sorghum-sudangrass) were characterized using a 28-day time series of replicated 16S rRNA gene and fungal ITS gene sequence libraries. The results from this study were published in 2013. In the second study, the effects of four types of isothiocyanates (ITCs), including allyl, butyl, phenyl, and benzyl ITC, on soil fungal and bacterial communities were determined. Each ITC was added to soil that also received 1% flax seedmeal (to represent organic material added by seedmeals). Microbial communities were analyzed based on the ITS gene for fungi and16S rRNA gene for bacteria using qPCR and tag-pyrosequencing with 454 GS FLX titanium technology. A manuscript based on these results was submitted for publication and is currently being revised based upon reviewer comments. In the first study, distinct separation occurred by amendment type, with mustard inducing large increases in the abundance of bacterial taxa associated with fungal disease suppression (e.g. Bacillus, Pseudomonas, and Streptomyces spp.). Dramatic shifts were seen among the fungi, too, with phylotype richness decreasing by > 60% following mustard addition. Changes in bacterial and fungal community composition were rapid, and distinct community types persisted throughout the study. In the second study, a dramatic decrease in fungal populations (~85% reduction) was observed after allyl ITC addition. Fungal community compositions also shifted following ITC amendments (e.g., Humicola increased in allyl and Mortierella in butyl ITC amendments). Bacterial populations were less impacted by ITCs with community compositions being primarily impacted by time of incubation. Our results indicate that the type of ITC released from seedmeals may result in differential impacts on soil microorganisms. This information will likely impact the selection and breeding of plants for biofumigation-based control of soil-borne pathogens while minimizing the impacts on non-target microorganisms.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Hollister, E.B., P. Hu, A.S. Wang, F.M. Hons, and T.J. Gentry. 2013. Differential impacts of brassicaceous and non-brassicaceous oilseed meals on soil bacterial and fungal communities. FEMS Microbiol. Ecol. 83:632-641.
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Progress 01/01/12 to 12/31/12
Outputs
OUTPUTS: Three laboratory and greenhouse studies were conducted to determine the impact of oilseed meals on soil microbial communities, nutrient cycling, and crop and weed survival and emergence. In the first study, soil microbial community responses to amendments of a glucosinolate-containing brassicaceous oilseed meal (Brassica juncea, mustard), a non-glucosinolate-containing, nonbrassicaceous oilseed meal (Linum usitatissimum, flax), and a nonoilseed biomass (Sorghum bicolor, sorghum-sudangrass) were characterized using a 28-day time series of replicated 16S rRNA gene and fungal ITS gene sequence libraries. In the second study, mustard and flax seed meals and sorghum-sudangrass were added to soil at levels of 0, 1, 2.5, and 5% (w/w) and changes in soil C, N, and other properties were measured along with changes in soil microbial communities. In the third study, a 14-day greenhouse study investigated whether Sinapis alba (white mustard), Brassica juncea (Indian mustard), Camelina sativa, and Jatropha curcas applied to soil at varying application rates [0, 0.5, 1.0, and 2.5% (w/w)] and incubation times (1, 7, and 14 d) prior to planting affected seed emergence and seedling survival of cotton [Gossypium hirsutum (L.)], sorghum [Sorghum bicolor (L.) Moench], johnsongrass (Sorghum halepense), and redroot pigweed (Amaranthus retroflexus). PARTICIPANTS: Project personnel included Anil Somenahally (postdoctoral research associate) and Ping Hu (Ph.D. student). TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
In the first study, distinct separation occurred by amendment type, with mustard inducing large increases in the abundance of bacterial taxa associated with fungal disease suppression (e.g. Bacillus, Pseudomonas, and Streptomyces spp.). Dramatic shifts were seen among the fungi, too, with phylotype richness decreasing by > 60% following mustard addition. Changes in bacterial and fungal community composition were rapid, and distinct community types persisted throughout the study. In the second study, both the type of amendment and application rate affected soil organic C, total C & N, and C & N mineralization. Mustard meal amendment initially inhibited C mineralization as compared to flax, but >50% of mustard and flax organic C was mineralized within 51 d. Nitrogen mineralization was similar for flax and mustard, except for the 2.5% rate for which a lower proportion of mustard N was converted to nitrate. The mustard meal greatly impacted microbial community composition, appearing to select for specific fungal populations. In the third study, with each species, emergence and survival was most decreased by 2.5% seed meal application applied at 1 and 7 d incubations. White mustard seed meal incubated for 1 d applied at low and high rates had similar negative effects on johnsongrass seedlings. Redroot pigweed seedling survival was generally most decreased by all 2.5% seed meal applications. The results indicate that oilseed meal amendment, and mustard in particular, has the potential to alter soil microbial community structure substantially. Thus, the potential varying impacts of different oilseed meals on soil ecosystems should be considered when developing recommendations for land application. In addition, the type, rate, and timing of seed meal application should be considered before land-applying seed meals in cropping systems.
Publications
- Hollister, E.B., P. Hu, A.S. Wang, F.M. Hons, and T.J. Gentry. 2012. Differential impacts of brassicaceous and non-brassicaceous oilseed meals on soil bacterial and fungal communities. FEMS Microbiol. Ecol. DOI: 10.1111/1574-6941.12020 (published online)
- Rothlisberger, K.L., F.M. Hons, T.J. Gentry, and S.A. Senseman. 2012. Oilseed meal effects on the emergence and survival of crop and weed species. Appl. Environ. Soil Sci. Vol 2012; Article ID 769357; 10 pages; doi:10.1155/2012/769357.
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Progress 01/01/11 to 12/31/11
Outputs
OUTPUTS: Laboratory studies were conducted to determine the impact of oilseed meals and isothiocyanates (ITCs) on Phymatotrichopsis omnivora (Duggar) Hennebert, the causal agent of cotton root rot. We investigated the effect of oilseed meals from both brassicaceous plants including mustard (Brassica juncea) and camelina as well as non-brassicaceous plants including jatropha, flax, and Chinese tallow on P. omnivora sclerotial germination and hyphal growth in Branyon clay soil, as well as the effects of 4 types of individual isothiocyanates (ITCs) including allyl, butyl, phenyl, and benzyl ITC on P. omnivora growth on potato dextrose agar (PDA). The oilseed meals were added to the soil at rates of 0%, 1%, and 5% (w/w). A second laboratory study was conducted to examine the impact of various oilseed meals on soil C, N, bacteria, and fungi. Mustard (B. juncea) and flax seed meals and sorghum-sudangrass were added to Weswood loam soil at levels of 0, 1, 2.5, and 5% (w/w). A third laboratory study was conducted to determine the soil microbial community responses to 4 types of ITCs (allyl, benzyl, phenyl, and butyl) in a microcosm study using Weswood loam soil. The microcosms were amended with an individual ITC and incubated for 28 days. Community qPCR assays were used to evaluate relative abundances of soil microbial populations after 2, 7, 14, 21, and 28 days. Soil microbial community composition after 2, 7, and 28 days was determined through tag-pyrosequencing using 454 GS FLX titanium technology, targeting ITS and 16S regions for fungal and bacterial communities respectively. PARTICIPANTS: Project personnel included Emily Hollister (assistant research scientist), Anil Somenahally (postdoctoral research associate), and Ping Hu (Ph.D. student). TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
In the first study, the results showed that all tested brassicaceous and jatropha seed meals were able to inhibit P. omnivora sclerotial germination and hyphal growth at 5% and 1% application rates respectively, with mustard seed meal being the most effective. Neither flax nor Chinese tallow showed any inhibitory effects on sclerotial germination. All tested ITCs inhibited P. omnivora OKAlf8 hyphal growth, although the level of inhibition varied with concentration. In the second study, both the type of amendment and application rate affected soil organic C, total C & N, and C & N mineralization. Mustard meal amendment initially inhibited C mineralization as compared to flax, but >50% of mustard and flax organic C was mineralized within 51d. Nitrogen mineralization was similar for flax and mustard, except for the 2.5% rate for which a lower proportion of mustard N was converted to nitrate. Soil bacterial and fungal community responses, for the 2.5% amendment rate, were characterized using replicated 16S rRNA and fungal ITS gene sequence libraries at 4 time points over the course of the laboratory incubation. Distinct separation of the bacterial and fungal communities occurred along amendment-type lines, with mustard inducing large increases in the abundance of bacterial groups (e.g., Bacillus, Pseudomonas and Streptomyces spp.) known to include many fungal disease-suppressing bacteria. Other amendments contributed to increased abundances of Actinobacteria or Bacteroidetes. Likewise dramatic shifts were seen among the fungi, with fungal phylotype richness decreasing by > 60% following mustard seed meal addition. Shifts in bacterial community composition slowed after 14 days but all biomass treatments still contained unique communities after 28 days. Similarly, changes among the fungi, especially for the mustard treatment, persisted throughout the entire study. In the third study, our results showed that the application of ITCs suppressed either soil fungal or bacterial abundance, depending upon the ITC applied, and altered soil microbial community composition. The allyl ITC greatly decreased soil fungal abundance by >6 times compared with the unamended control and significantly changed both fungal and bacterial community composition. In contrast, butyl ITC had a larger impact on bacterial rather than fungal abundance and composition. This series of laboratory studies indicated that: 1)Seedmeals of several brassicaceous species as well as jatropha may have potential for inhibiting P. omnivora, thus possibly reducing cotton root rot. 2)The potential varying impacts of different oilseed meals on soil ecosystems (e.g., C & N cycling) should be considered when developing recommendations for land-application. 3)Oilseed meal amendment has the potential to substantially alter soil microbial community structure, particularly in the case of mustard, which may help to further explain the mechanisms responsible for disease suppression following biofumigation with brassicaceous oilseed meals. 4)The incorporation of different ITCs could differentially impact soil microbial populations and community composition.
Publications
- Hollister, E.B., P. Hu, A.S. Wang, F.M. Hons, and T.J. Gentry. 2011. Soil bacterial and fungal community responses to oilseed meal addition. In Abstracts, 111th General Meet., ASM, New Orleans, LA. 21-24 May 2011. ASM, Washington, D.C.
- Hu, P., A. Somenahally, F.M. Hons, and T. Gentry. 2011. Metagenomics-based analysis of fungal and bacterial communities in isothiocyanate-amended soil. In Abstracts, 3rd Annual Argonne Soil Metagenomics Workshop, Chicago, IL, 5-7 October 2011.
- Hu, P., A.S. Wang, A.S. Engledow, E.B. Hollister, K.L. Rothlisberger, J.E. Matocha, D.A. Zuberer, T.L. Provin, F.M. Hons, and T.J. Gentry. 2011. Inhibition of the germination and growth of Phymatotrichopsis omnivora (Cotton Root Rot) by oilseed meals and isothiocyanates. Appl. Soil Ecol. 49:68-75.
- Somenahally, A., L.P. Moncayo, and T. Gentry. 2011. Impact of mustard (Brassica juncea) and flax (Linum usitatissimum) seed meal amendments on soil nitrogen dynamics and microbial community composition. In Abstracts, ASA-CSSA-SSSA Annual Meet., San Antonio, TX. 16-19 October 2011.
- Wang, A.S., P. Hu, E.B. Hollister, K.L. Rothlisberger, A. Somenahally, T.L. Provin, F.M. Hons, and T.J. Gentry. 2012. Impact of Indian mustard (Brassica juncea) and flax (Linum usitatissimum) seed meal applications on soil carbon, nitrogen, and microbial dynamics. Appl. Environ. Soil Sci. Vol 2012; Article ID 351609; 14 p; doi:10.1155/2012/351609.
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