Progress 02/01/17 to 01/31/20
Outputs
Target Audience:Throughout this project I interacted with multiple audiences. I shared project results from this project at conferences and workshops, and manuscripts are in preparation for submission to peer-reviewed journals. I targeted broader audiences and stakeholders through the Innovation Center for Sustainable Agriculture, participation in field days, collaborating with participating producers, and the Colorado Collaborative for Healthy Soils. My outreach efforts for grades K-12 included classroom demonstrations and activities at a local elementary school, serving on the planning committee for a one-day workshop (Expanding Your Horizons) for middle school girls interested in STEM, and serving as a mentor for high school women in the PROGRESS (PROmoting Geoscience Research Education & succesS) program. My efforts involving university-level (or above) focused on training, mentoring, and class-room instruction with undergraduate and graduate students. I mentored one undergraduate at UC Davis, one undergraduate student through the CSU SUPER (Skills for Undergraduate Participation in Ecological Research) program, two undergraduate students through the REEU Integrative Agroecology Sustainability Research summer program, and one post grad agroecology student who is now pursuing a PhD in agricultural science and soil ecology. I interacted with several graduate students through the Summer Soil Institute held at CSU where I helped develop program material and assisted with training attendees in various methods used in soil ecology. I am a mentor for WISE (Women in Soil Ecology), which is an international mentoring network for graduate students. I helped develop and teach a graduate student seminar on soil health and gave numerous guest lectures and invited talks designed for various audiences including academic researchers, students and broader agricultural stakeholder groups. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?There have been ample opportunities for training and professional development throughout this project. I acquired new skills, expanded my professional network, worked with new collaborators, gained proficiency in new analytical methods, and developed my mentorship and teaching skills. Most recently, I organized and convened a symposium at the Soil Science Society of America meeting (November 2019, San Antonio Texas) entitled "Managing plant-soil-microbe partnerships for soil C stabilization and nutrient cycling from genes to landscapes". I helped plan and lead a women in STEM mentoring and networking workshop at CSU in January 2019, and I co-taught (and developed) a graduate seminar course (ECOL 592) - "Growing a revolution from the ground up: A comprehensive exploration of soil health" - in Spring semester 2019. Other workshops I attended during this project include "Microbial Communities to Mitigate Climate Change" at the Marine Biological Lab (Woods Hole, MA) in September 2018, and the "Responsible Conduct of Research" workshop atCSU where wediscussed research ethics, data management, authorship, mentorship, and leadership skills. I have acquired new analytical skills including root exudate chemistry metabolomics using a time of flight mass spectrometer (qTOF-MS) and microbial sequencing analyses. I acquired these skills by working with an analytical chemist and microbiologist, and attending a microbiomebioinformatics workshop held at CSU. The bioinformatics workshop focused on how to manage and analyze microbial sequencing datasets using a widely-used program, Qiime2. I learned the basics of microbiome science, how to access a remote server for data processing, basic Linux and terminal commands, and analysis of 16S rRNA data.I gained valuable supervisory skills through numerous mentorship experiences, as detailed elsewhere. How have the results been disseminated to communities of interest?I have presented the results of this project at conferences, workshops, and symposiums. Manuscripts are in preparation and will be submitted to peer-reviewed journals. I participated in and organized several outreach activities with primary and middle school students. These activities were designed to teach the importance of sustainable agriculture and soil health through hands-on science activities. I have given guest lectures and mentored several undergraduate students working towards ecological and agricultural degrees. My mentees also presented findings from this project at scientific conferences and undergraduate research symposiums at CSU. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
I designed a series of greenhouse experiments with different maize varieties to determine if rhizosphere microbial structure and function is influenced by crop genotype, and whether these effects persist under different environmental conditions. Each experiment consisted of two maize genotypes: (1) teosinte--the ancient, closest living wild-relative of maize and (2) a modern variety--the product of intensive breeding practices. I employed genomic, metabolomic, and microbial functional assays to advance our understanding of crop genotype effects on rhizosphere microbiome structure (Obj. 1) and function (Obj. 2) and consequent benefits to crop health under different environments (Obj. 4). I characterized plant traits (e.g. belowground biomass, root exudation rate, plant metabolites) important for the recruitment and activity of the rhizosphere microbiome (Obj. 3). In this reporting period, we completed all analyses for two greenhouse experiments. All data acquired has been prepared for publication including statistical analyses and compilation of tables and graphs for manuscripts in preparation. Here I outline the major results from the last reporting period, add broader context with findings throughout the project, and highlight information that has advanced our understanding of plant-microbial interactions. To characterize whether genotype and/or soil environment influences root exudation (rate and chemical diversity, Obj. 3) and rhizosphere microbiome community composition (Obj. 1 and 4), I performed a common garden experiment with each genotype grown in both their "home" soil that had been conditioned by the same genotype (e.g. modern genotype grown in modern-conditioned soil), and their "away" soil that was conditioned by the other genotype (e.g. ancient genotype grown in modern genotype-conditioned soil). I hypothesized that modern maize, bred under high inputs, may have lost necessary traits (adequate root carbon supply) to support a diverse and active rhizosphere microbiome. I characterized plant traits and examined the effect of maize genotype (teosinte and modern hybrid) on root exudation rate and chemical composition, rhizosphere microbial community composition and nutrient cycling, and plant nutrient uptake. I found that modern varieties had 1.4 times faster growth rates, higher leaf chlorophyll contents, and greater above- and below- ground biomass than teosinte. However, the aboveground:belowground ratio was conserved across genotypes and unaffected by soil environment. To evaluate the effects of root phenotypic characteristics on root exudation rate, I used stepwise regressions and AIC model selection. The stepwise regressions included root length, mass, volume, surface area, and the amount of tips, forks, and crossings. Root volume was the single most important root characteristic (lowest AIC score) explaining variation in root exudation rates; thus, all root exudation rates were normalized by root volume to evaluate treatment effects. We found no effect of genotype or soil type (home/away) on root exudation rate, but root exudate metabolite diversity and composition were affected by both genotype and soil condition. We identified nine root exudate metabolites that were sensitive to changes in the soil environment (e.g. shifted from high to low concentration) and another six metabolites whose abundance remained conserved with maize genotype regardless of soil type. We also examined rhizosphere microbial community composition and genes involved in nitrogen cycling. Teosinte's rhizosphere microbiome was more diverse and had greater abundance of acidobacteria, planctomycetes and nitrospiraea and lower relative abundance of actinobacteria than modern maize. Of the six N cycling genes evaluated NifH, involved in biological N fixation, was greater in the rhizosphere of teosinte than that of modern maize. NifH gene abundance was positively correlated with aboveground biomass N. Root exudation rate was also correlated with aboveground biomass N, but only in teosinte plants. The rhizosphere microbial community composition of modern maize was unaffected by soil type ("home" or "away" treatments), which suggests that this modern maize variety was unable to take advantage of the diverse microbial communities present in soil conditioned by teosinte. Thus, host selection processes moderate rhizosphere microbial community structure and activity and plant genotype dictates microbial community diversity, recruitment of specific taxa, and N-cycling pathways in the rhizosphere. Taken together, these results demonstrate the potential mechanisms by which maize genotype-microbial interactions may facilitate the development of high-yielding crops that also foster a beneficial microbiome, contributing to more sustainable agriculture systems. The closest wild relative of modern maize varieties, Balsas teosinte, is adapted to extreme environmental conditions and a highly cyclical (wet-dry season), Central American climate. Because of this, teosinte may be better able to support a healthy rhizosphere microbiome in stressed conditions (e.g. drought, rapid and extended flooding). In another greenhouse experiment, we tested if maize genotype had a significant influence on rhizosphere microbial activity, and if these effects persisted or emerged under drought stress (Obj. 4). We grew both teosinte and a modern hybrid variety under different water conditions and measured rhizosphere microbial biomass and extracellular enzyme activities that are important for nutrient cycling (β-Glucosidase, β-D-cellubiosidase, α-Glucosidase, N-acetyl-β-Glucosaminidase, Phosphatase, β-Xylosidase). We expected teosinte to foster greater rhizosphere microbial biomass and activity than the modern variety and hypothesized that these differences would be greatest under low soil moisture conditions. We found that rhizosphere microbes associated with modern corn had 2-3 times higher enzyme activities than teosinte at moderate soil moisture (20% GWC), despite having similar microbial biomass. Under the lowest (5% GWC) and highest (50% GWC) soil moisture treatments, microbial enzyme activity was significantly reduced in modern varieties. In contrast, teosinte microbial enzyme activity was maintained at similar levels across all water treatments and had 50% greater microbial enzyme activities at the highest soil moisture. These trends are reflected across all C-, N-, and P- acquiring enzymes measured. Even though modern corn had nearly five times more microbial biomass than teosinte at the lowest soil moisture level, microbial activity was the same. This could be driven by reductions in carbon supply belowground when modern maize is subjected to water stress. Modern maize had more root biomass than teosinte, but both high and low water treatments significantly reduced root biomass in modern maize and not teosinte. These results suggest modern varieties are less capable of supporting an active microbial community when exposed to water stress.
Publications
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2019
Citation:
"Managing plant-soil-microbe partnerships for soil C stabilization and nutrient cycling from genes to landscapes", Soil Science Society of America Symposium, November 2019
- Type:
Journal Articles
Status:
Accepted
Year Published:
2020
Citation:
Li M, Schmidt JE, LaHue DG, Lazicki PA, Kent A, Machmuller MB, Scow KM, Gaudin ACM. 2020. Impact of irrigation strategies on tomato root distribution and rhizosphere processes in an organic system. Frontiers in Plant Science, doi:10.3389/fpls.2020.00360
- Type:
Journal Articles
Status:
Accepted
Year Published:
2020
Citation:
Tan X, Machmuller MB, Huang F, He J, Chen J, Cotrufo MF, Shen W. 2020. Temperature sensitivity of ecoenzyme kinetics driving litter decomposition: The effects of nitrogen enrichment, litter chemistry, and decomposer activity. Soil Biology and Biochemistry, doi:10.1016/j.soilbio.2020.107878
- Type:
Journal Articles
Status:
Accepted
Year Published:
2020
Citation:
Tan X, Machmuller MB, Cotrufo MF, Shen W. 2020. Shifts in litter quality and hydrolytic enzyme activity explain different responses of litter decomposition to nitrogen addition. Biology and Fertility of Soils 56:423-438
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2019
Citation:
Hwang, S., Machmuller, MB. Going back to the roots: evaluating the influence of ancient and modern maize on microbial nutrient cycling. Soil Ecology Society Conference, May 2019
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2021
Citation:
Machmuller MB, Ippolito J, Silver H, Neumeyer M. The Colorado Collaborative for Healthy Soils: A community approach to cultivate sustainable solutions. Food and Farm Forum, January 2021
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Progress 02/01/18 to 01/31/19
Outputs
Target Audience:In this reporting period I interacted with multiple audiences within and outside the academic setting. I continued many of my outreach efforts from the first program year and these included interacting with K-12 students via (1) in-classroom outreach activities for primary school (3rdand 4thgrade) students at a local Fort Collins, CO elementary school, and (2) a one-day workshop (Expanding Your Horizons) for middle school (6th-8thgrade) girls interested in STEM. My efforts involving university-level and beyond focused on training, mentoring, and class-room instruction with undergraduate and graduate students at University of California-Davis (UC-Davis) and Colorado State University (CSU). I mentored two undergraduate students through the REEU Integrative Agroecology Sustainability Research summer program and interacted with several graduate students during the Summer Soil Institute held at CSU where I helped develop program material and assisted with training attendees in various methods used in soil ecology. Changes/Problems:During this reporting period, I requested and received a grant conversion (postdoctoral fellowship to standard grant) and 1-year extension, upon the transition to my new position as Research Scientist II and joint assistant faculty in Soil & Crop Sciences at CSU. Upon this request, aprogress report, updated budget and revised timeline was submitted to and approved bythe acting program manager. What opportunities for training and professional development has the project provided?I have acquired new analytical skills through my work and training for the qTOF-MS root exudate chemistry analyses. I helped develop a graduate seminar course (ECOL 592) - "Growing a revolution from the ground up: A comprehensive exploration of soil health" - that I will co-teach in Spring semester 2019. I attended a workshop entitled "Microbial Communities to Mitigate Climate Change" at the Marine Biological Lab (Woods Hole, MA) in September 2018. I gained many valuable supervisory skills through my mentorship experiences, and I submitted a symposium proposal - "Managing plant-soil-microbe partnerships for soil C stabilization and nutrient cycling from genes to landscapes"- for the Soil Science Society of America Meeting to be held in November 2019. How have the results been disseminated to communities of interest?Within this reporting period, I participated in and organized several outreach activities with primary and middle school students. With these activities I aimed to serve as a role model, teach the importance of sustainable agriculture and soil health, and enhance learning experiences through hands-on science activities. I also served on the planning committee for a one-day workshop held specifically for middle school girls interested in STEM. The conference includes several hands on workshops led by women scientists. Our goal is to motivate, inspire, and encourage young women interested in STEM. I have disseminated the knowledge gained throughout this project to several undergraduate students working towards ecological and agricultural degrees. Specifically, I mentored and trained two undergraduates and gave three talks, and my students presented their results at the REEU symposium at CSU. What do you plan to do during the next reporting period to accomplish the goals?During the next reporting period I plan to complete microbial DNA sequencing to distinguish taxonomic differences in the microbes recruited by each genotype (Obj. 1). I will analyze primary and secondary metabolites in root exudates (Obj. 3) using high-resolution quadrupole time of flight mass spectrometry (qTOF-MS). The qTOF-MS analysis required a lot of method development, which was done in collaboration with an analytical chemist. Using the data acquired I will determine the overlapping and distinct root exudate compounds; a targeted approach to identify specific mechanisms responsible for microbial recruitment and function. I also plan on completing analyses for microbial community composition, microbial N-cycling genes, and finishing the current greenhouse experiment and soil and plant analyses including plant-available nutrients, above- and below- ground plant biomass and chemistry, soil microbial biomass and extracellular enzyme assays.
Impacts
What was accomplished under these goals?
I have addressed my project objectives using a unique panel of corn genotypes (available through collaborator A. Gaudin, UC-Davis) spanning ~9,000 years of evolutionary history. In this project period, I completed one greenhouse experiment and one is ongoing. For these experiments, I utilized two maize genotypes: (1) teosinte--the ancient, closest living wild-relative of maize and (2) a modern variety--the product of intensive breeding practices. The series of greenhouse experiments were designed to determine if rhizosphere microbial structure and function is influenced by maize genotype, and whether these effects persist under different environmental conditions. In order to parse out the influence of soil environment (microbial community and soil chemistry status) and plant genotype, I performed a common garden experiment with each genotype grown in both their "home" soil that had been conditioned by the same genotype (e.g. modern genotype grown in modern-conditioned soil), and their "away" soil that was conditioned by the other genotype (e.g. ancient genotype grown in modern genotype-conditioned soil). I measured the rate and chemical composition of root carbon supply to determine if root exudation amount or chemistry drives microbial recruitment and if the soil environment influenced microbial recruitment more so than plant-traits alone. Thus far, I have harvested this greenhouse experiment and completed many of the analyses including: plant growth, aboveground and belowground biomass, plant chemistry, and root exudation rate. I have extracted microbial DNA and completed method development for root exudation chemistry using quadrupole time of flight mass spectrometry (qTOF). We found higher root exudation rates in modern varieties, but lower microbial enzyme activities involved in C and N cycling. We found specific root exudate compounds more sensitive to soil condition and others more sensitive to genotype. We are currently exploring root exudation chemical diversity and N-cycling microbial genes to more clearly identify these shifts in plant-microbial interactions. The results thus far demonstrate the potential mechanisms by which maize genotype-microbial interactions may facilitate the development of high-yielding crops that also foster a beneficial microbiome, contributing to more sustainable agriculture systems. The ongoing greenhouse experiment was designed to gain a more comprehensive understanding of the genotype x environment interaction (Obj. 4). I am growing both ancient and modern varieties under different nutrient and water conditions. Our nitrogen treatments include inorganic (nitrate) and organic N (cover crop residue), and our water treatments include low (drought conditions), moderate, and excessive irrigation. We will determine if plant-microbe interactions are influenced by environmental conditions, and if this response varies with maize genotype.
Publications
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2018
Citation:
Machmuller, M.B*. Secrets below: how the hidden world of soils could hold the key to the future health of our planet. Creighton University Environmental Science Annual Banquet, April 2018, *Distinguished Alumni Invited Speaker
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2018
Citation:
Trimarco, T. Wang, T., Hwang, S., Machmuller MB. Evaluating the rhizosphere of maize subspecies under different moisture conditions. REEU Symposium, CSU, July 2018.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2018
Citation:
Wang, T., Trimarco, T, Hwang, S., Machmuller MB. Interaction between root exudates and rhizosphere microbiome in maize. REEU Symposium, CSU, July 2018.
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Progress 02/01/17 to 01/31/18
Outputs
Target Audience:Within the first year I have interacted with multiple audiences within and outside the academic setting. My efforts that focused on reaching K-12 students included (1) in-classroom outreach activities for primary school (3rd and 4th grade) students at a local Fort Collins, CO elementary school, and (2) out-of-classroom, one-day workshop for middle school (6th-8th grade) girls interested in STEM. My efforts involving university-level and beyond focused on training, mentoring, and class-room instruction with undergraduate students at University of California-Davis (UC-Davis) and Colorado State University (CSU), a post-graduate Agricultural Science student (CSU), graduate student (CSU), and postdoctoral researcher (UC-Davis). My direct mentorship and training experiences included five ethnic minority students, of which three were first-generation students. Outside of academia, I focused on the applicationof my research activiteis by collaborating with a large, organic farm in California. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?I attended the Responsible Conduct of Research workshop held atColorado State University, where we discussed research ethics, data managment, authorship, mentorship, and leadership. This workshop was very useful and I will continue to apply the information I learned from this workshop when conducting research, collaborating, or mentoring. I also attended a microbiomebioinformatics workshop held at Colorado State University. This workshop focused on how to manage and analyze microbial sequencing datasets.I learned the basics of microbiome science, how to access a remote server for data processing, basic Linux and terminal commands, and analysis of 16S rRNA data using Qiime2. How have the results been disseminated to communities of interest? Within the first year I have interacted with multiple audiences within and outside the academic setting. I participated in and organized several outreach activities with primary (3rd and 4th grade) and middle school (6th-8th grade) students. With these activities I aimed to serve as a role model, teach the importance of sustainable agriculture and soil health, and enhance learning experiences through hands-on science activities. For example, I serve on the planning committee for a one-day workshop held specifically for middle school girls interested in STEM. The conference includes several hands on workshops led by women scientists. Our goal is to motivate, inspire, and encourage young women interested in STEM. I have also mentored and trained undergraduate, post-graduates, and graduate students in the first year of funding. At the University of California-Davis I mentored and trained two undergraduate students with agricultural science majors, both of who were minorities and first generation students. At Colorado State University, I have mentored and trained a post-graduate, first-generation, minority who is interest in pursuing a PhD in agricultural science. I gave two guest lectures and, through formal classroom instruction, I have reached undergraduate students with ecological and agricultural majors. I have also helped train and mentor a graduate student (first generation student, minority, Colorado State University) and a postdoc (minority, UC-Davis) that were interested in using the same techniques I developed for my USDA project. Through collaborations with a large organic farm in California, I was able to collect soils and obtain important information regardingon-farm management practices, land-use history, management challenges and concerns. I was also able to discuss my research objectives and goalsand develop a network forinformation exchange in order to share resultsand discuss the direct application of my project. What do you plan to do during the next reporting period to accomplish the goals?In the next reporting period, I plan to finish the analyses not yet completed from the samples collected in the experiments conducted. I plan to further address the genotype x environment interaction objective, if feasible and appropriate given the results from these experiments. The analyses ongoing includesdetailed chemistry of root exudates, microbial communityanalyses (16S rRNA sequencing), and microbial functional assays. I plan to present my research, organize a conference symposium, and continue to build on the mentorship and outreach activities.
Impacts
What was accomplished under these goals?
My project aims to increase our understanding of how crop domestication and breeding have impacted the microbial (bacteria and fungi) communities that live around the root, called the rhizosphere microbiome. The rhizosphere microbiome help make nutrients available for plant uptake and fight off pathogens that can be harmful to crops. Developing crops that take advantage of a beneficial rhizosphere microbiome can provide many cascading effects on crop health, including improved drought tolerance, nutrient use efficiency, and yield stability. Such improvements could lead to reduced inputs needed to sustain crop health; providing both economic and environmental benefits on and off the farm. However, we currently lack the details necessary for such developments to occur. I have addressed my project objectives using a unique panel of corn genotypes (available through collaborator A. Gaudin, UC-Davis) spanning ~9,000 years of evolutionary history. I have completed two eight-week greenhouse experiments with two genotypes: (1) teosinte--the ancient, closest living wild-relative of maize and (2) a modern variety--the product of intensive breeding practices. The objective of the first greenhouse experiment was to determine maize genotype impacts on the (1) type of microbes recruited and living in the root zone (microbial community structure), (2) microbial functions important to crop health, and (3) amount and chemistry of root exudates produced (a plant trait important for the recruitment and survival of rhizosphere microbes). For the first experiment, I grew the ancient- and modern- maize genotypes under the same conditions (temperature, moisture, soil type). I measured plant growth and health through detailed observations including: plant height, leaf chlorophyll content, pest infestation, leaf discoloration, and amount of leaves and tillars produced. At harvest (eight weeks), I collected root exudates, rhizosphere and non-rhizosphere soils to be used for a suite of soil chemistry analyses and microbial community taxonomic and functional analyses. In the second greenhouse experiment, I aimed to characterize the 'environment' x genotype interaction. In order to parse out the influence of soil environment (microbial community and soil chemistry status) and plant genotype, I performed a common garden experiment with each genotype grown in both their "home" soil conditioned by the same genotype in the first greenhouse experiment (e.g. modern genotype grown in modern-conditioned soil) and their "away" soil conditioned by the other genotype (e.g. ancient genotype grown in modern genotype-conditioned soil). We used the same collection procedures and analyses described above. The combination of both experiments was designed so that I could decipher whether soil condition influenced microbial recruitment more so than plant-traits alone. The greenhouse experiments and sampling procedures used for this project required methodological experiments and trials. For example, collecting root exudates is difficult and methodologically challenging, but I managed to modify existing methods to successfully collect and analyze samples. For each experiment I collected root exudates, rhizosphere and bulk soils, and belowground and aboveground plant biomass. Root exudates were analyzed for C concentration and have been prepared for detailed chemical analysis (e.g. the type and diversity of C compounds). Plant biomass samples were dried, weighed, and prepared for nutrient analysis. At the time of sampling, soil (rhizosphere and bulk) was prepared and stored for microbial community assays, microbial community taxanomic identification (e.g. sequencing for microbial community profiles), and chemical analysis. I found that modern varieties had 1.4 times faster growth rates, higher leaf chlorophyll contents, and greater above- and below- ground biomass than teosinte (p < 0.05). While growth rate and aboveground biomass was unaffected by soil environment, I found that--independent of genotype--plants grown in teosinte-conditioned soil and non-conditioned control soil tended to be higher than plants grown in modern-conditioned soil, although not highly significant (p = 0.096). However, the aboveground:belowground ratio was conserved across genotypes and unaffected by soil environment. To evaluate the effects of root phenotypic characteristics on root exudation rate, I used stepwise regressions and AIC model selection. The stepwise regressions included root length (cm), mass (g), volume (cm3), surface area (cm2), and the amount of tips, forks, and crossings. Root volume was the single most important root characteristic (lowest AIC score) explaining variation in root exudation rates (p = 0.001). When normalized by root volume, I found higher root exudation rates in modern varieties (μg C cm-3) compared to ancient varieties (p<0.05), but no effect of soil type/ conditioning. In other words, growing maize varieties in "home" soil (conditioned by same genotype) or "away" soil (conditioned by the other genotype) had no effect on root exudation rate. Despite the soil environment, modern varieties had 2.6 times higher production of root exudate C than teosinte. With a subset of soils, I completed the method development for several microbial extracellular enzyme assays. I determined the maximum catalytic enzyme activity (Vmax) of seven different hydrolytic enzymes that are produced by microbes for nutrient acquisition and can be important for pathogen resistance. In order to make comparisons across genotypes, these method developments were required verify substrate concentrations able to capture maximum enzyme catalytic activity. Overall, both rhizosphere and bulk soils have much higher phosphatase and glucosidase activity than any of the other enzymes measured (cellobiosidase, N-acetyl glucosidase, xylosidase). Now that method development is complete, each sample is being analyzed to determine the influence of genotype on microbial community functions important for crop health.
Publications
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2017
Citation:
Machmuller, M.B., Gaudin, A., Wallenstein, W. Crop domestication and breeding impacts on microbially-mediated plant health. Natural Resource Ecology Laboratory 50th Anniversary Symposium, Ignite Presentation, November 2017.
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