My review on Plant-Microbial Interactions in Agriculture got published!

A few months ago, I was invited to submit an article to the special issue “Plant Probiotic Bacteria: solutions to feed the World” in AIMS Microbiology on the interactions between agricultural plants and microorganisms.  As my relevant projects are still being processed, I chose to write a review of the current literature regarding these interactions, and how they may be altered by different farming practices.  The review is available as open-access here!

“Plant-microbial interactions in agriculture and the use of farming systems to improve diversity and productivity”

A thorough understanding of the services provided by microorganisms to the agricultural ecosystem is integral to understanding how management systems can improve or deteriorate soil health and production over the long term. Yet it is hampered by the difficulty in measuring the intersection of plant, microbe, and environment, in no small part because of the situational specificity to some plant-microbial interactions, related to soil moisture, nutrient content, climate, and local diversity. Despite this, perspective on soil microbiota in agricultural settings can inform management practices to improve the sustainability of agricultural production.

Keywords bacteria; climate change; farming system; fungi; nutrient exchange; pathogens; phytohormones

Citation: Suzanne L. Ishaq. Plant-microbial interactions in agriculture and the use of farming systems to improve diversity and productivity. AIMS Microbiology, 2017, 3(2): 335-353. doi: 10.3934/microbiol.2017.2.335

A collaborative project on sheep feed efficiency and gut bacteria was published!

I’m pleased to announce that a paper that I contributed to was recently accepted for publication in the Journal of Animal Science!

“Feed efficiency phenotypes in lambs involve changes in ruminal, colonic, and small intestine-located microbiota”, Katheryn Perea; Katharine Perz; Sarah Olivo; Andrew Williams; Medora Lachman; Suzanne Ishaq; Jennifer Thomson; Carl Yeoman (article here).

Katheryn is an undergraduate at New Mexico Institute of Mining and Technology who received an INBRE grant to support her as a visiting researcher at Montana State University in Bozeman, MT over summer 2016.  Here, she worked with Drs. Carl Yeoman and Jennifer Thomson to perform the diversity analysis on the bacteria in the gastrointestinal tract of sheep from a previous study.  These sheep had been designated as efficient or inefficient, based on how much feed was needed for them to grow.  Efficient sheep were able to grow more with less feed, and it was thought this might be due to hosting different symbiotic bacteria which were better at fermenting fibrous plant material into usable byproducts for the sheep.

Samples from the sheep were collected as part of a larger study on feed efficiency performed by MSU graduate students Kate Perz and Medora Lachman, as well as technicians Sarah Olivo and Andrew Williams, and Katheryn performed the data and statistical analysis using some of my guidelines.  This is Katheryn’s first published article, and one I just presented a poster on at the Congress on Gastrointestinal Function in Chicago, IL!

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2017 Congress on Gastrointestinal Function

I just got back from my very first Congress on Gastrointestinal Function, poster tube.jpga small meeting for  researchers with a specific focus on the gastrointestinal tract, which is held every two years in Chicago, Illinois.  The special session this year was on “Early Acquisition and Development of the Gut Microbiota: A Comparative Analysis”.  The rest of the sessions opened up the broader topics of gut ecosystem surveillance and modulation, as well as new techniques and products with which to study the effect of microorganisms on hosts and vice versa.  The research had a strong livestock animal focus, as well as a human health focus, but we also heard about a few studies using wild animals.

As I’ve previously discussed, conferences are a great way to interact with other scientists.  Not only can you learn from similar work, but you can often gain insights into new ways to solve research problems inherent to your system by looking at what people in different fields are trying, something that you might otherwise miss just by combing relevant literature online.  A meeting or workshop is also a great place to meet other similarly focused scientists to set up collaborators that span academia, government, non-profit, and industry sectors.

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It was great to catch up with Dr. Ben Wenner, now at Purdue Agribusiness, and meet Yairy Roman-Garcia, grad student at the Ohio State University.

This year, I was excited for one of my abstracts to be accepted as a poster presentation, and honored to have the other upgraded from poster to talk!  Stay tuned for details about both of those projects in the coming weeks, and be sure to check this meeting out in April, 2019.

2016 Year In Review

Looking back

2016 started with a bang when I launched this site and joined Twitter for the first time!  For the first quarter of the year, I was a post-doctoral researcher in the Yeoman Lab in the Department of Animal and Range Sciences at Montana State University.  I was working on a total of eight grants, ranging from small fellowships to million dollar projects, both as a principal investigator and as a co-PI.  I was also doing the bioinformatic analysis for multiple projects, totaling nearly 1,000 samples, as well as consulting with several graduate students about their own bioinformatic analyses.

In late spring, my position in the Yeoman lab concluded, and I began a post-doctoral position in the Menalled Lab in the Department of Land Resources and Environmental Sciences at MSU.  This position gave me the opportunity to dramatically increase my skill-set and learn about plant-microbe interactions in agricultural fields.  My main project over the summer was studying the effect of climate and other stresses on wheat production and soil microbial diversity, and this fall I have been investigating the legacy effects of these stressors on new plant growth and microbial communities.  I have extracted the DNA from all of my Fort Ellis summer trial soil samples, and look forward to having new microbial data to work with in the new year.  Based on the preliminary data, we are going to see some cool treatment effects!

Over the summer, I attended the American Society for Microbiology in Boston, MA in June, where I presented a poster on the microbial diversity in organic and conventional farm soil, and the Joint Annual Meeting for three different animal science professional societies in Salt Lake City, UT in July, where I gave my first two oral conference presentations. One was on the effect of a juniper-based diet on rumen bacteria in lambs, and the other was on the biogeography of the calf digestive system and how location-specific bacteria correlate to immune-factor expression.

Thanks to a lot of hard work from myself and many collaborators, a number of research projects were accepted for publication in scientific journals, including the microbial diversity of agricultural soils, in reindeer on a lichen diet, and in relation to high-fat diets in mice, it also included work on virulent strains of Streptococcus pyogenes, and a review chapter on the role of methanogens in human gastrointestinal disease.

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Looking forward

A whopping thirteen manuscripts are still in review at scientific journals or are in preparation waiting to be submitted! Some of those are primarily my projects, and for others I added my skills to the work of other researchers.  Editing all those is going to keep me plenty busy for the next few months. I’ll also be writing several more grants in early 2017, and writing a blog post about the Herculean task that can be.

I’ll be concluding my greenhouse study by March of 2017, just in time to prepare for another field season at Fort Ellis, on the aforementioned climate change study that is my main focus. In January, I’ll be spending time in the lab helping to process and sequence DNA from my 270 soil samples, and begin the long task of data quality assurance, processing, and analysis.  I’m not worried, though, 270 samples isn’t the most I’ve worked with and bioinformatic analysis is my favorite part of the project!

This year, I am hoping to attend two conferences that I have never previously attended, and present data at both of them.  The first will be the 2017 Congress on Gut Function in Chicago, IL in April, and the second will be the Ecological Society of America’s Annual Meeting in Portland, OR in August.  Both conferences will give me the opportunity to showcase my work, network with researchers, and catch up with old friends.

If 2017 is anything like the past few years, it’s going to be full of new projects, new collaborators, new skills, and new opportunities for me, and I can’t wait!  So much of what I’ve accomplished over the last year has been possible because of the hard work, enthusiasm, and creativity of my colleagues, students, friends, and family, and I continue to be grateful for their support.  I’d also like to thank anyone who has been kind enough to read my posts throughout the last year; it’s been a pleasure putting my experiences into words for you and I appreciate the time and interest you put in.  I look forward to sharing more science with you next year!

Manuscript published on the effect of low/high fat diets on health and intestinal bacteria

Several years ago, during my Ph.D. at the University of Vermont, I provided wet-lab and DNA sequence analysis work for a project investigating the health effects of a low or high fat diet on mice with Dr. Huawei Zeng of the USDA Agricultural Research Service.  It was just recently published in the Journal of Nutritional Biochemistry!

Abstract

Consumption of an obesigenic/high-fat diet (HFD) is associated with a high colon cancer risk and may alter the gut microbiota. To test the hypothesis that long-term high-fat (HF) feeding accelerates inflammatory process and changes gut microbiome composition, C57BL/6 mice were fed HFD (45% energy) or a low-fat (LF) diet (10% energy) for 36 weeks. At the end of the study, body weights in the HF group were 35% greater than those in the LF group. These changes were associated with dramatic increases in body fat composition, inflammatory cell infiltration, inducible nitric oxide synthase protein concentration and cell proliferation marker (Ki67) in ileum and colon. Similarly, β-catenin expression was increased in colon (but not ileum). Consistent with gut inflammation phenotype, we also found that plasma leptin, interleukin 6 and tumor necrosis factor α concentrations were also elevated in mice fed the HFD, indicative of chronic inflammation. Fecal DNA was extracted and the V1–V3 hypervariable region of the microbial 16S rRNA gene was amplified using primers suitable for 454 pyrosequencing. Compared to the LF group, the HF group had high proportions of bacteria from the family Lachnospiraceae/Streptococcaceae, which is known to be involved in the development of metabolic disorders, diabetes and colon cancer. Taken together, our data demonstrate, for the first time, that long-term HF consumption not only increases inflammatory status but also accompanies an increase of colonic β-catenin signaling and Lachnospiraceae/Streptococcaceae bacteria in the hind gut of C57BL/6 mice.

Paper published on the gut diversity of reindeer on a lichen diet

A manuscript that I helped co-author, “Rumen and cecum microbiomes in reindeer (Rangifer tarandus tarandus) are changed in response to a lichen diet and may effect enteric methane emissions” was just accepted for publication in PLOS ONE.  In 2012 I went to Norway to apprentice for two weeks in the lab of Dr. Monica Sundset, and in 2013, Monica’s graduate student Alex came to the University of Vermont to apprentice in Dr. Andre Wright’s lab, where I taught him quantitative real-time PCR and some bioinformatics.  Alex performed a feeding trial back in Norway, in which reindeer were fed a lichen-based diet, in order to assess changes in microbial diversity.  Lichens contain usnic acid, which is toxic to ruminants.  Reindeer; however, host some unique bacteria which degrade usnic acid in the rumen and allow the reindeer to eat them without dietary problems.

 

“Abstract

Reindeer (Rangifer tarandus tarandus) are large Holarctic herbivores whose heterogeneous diet has led to the development of a unique gastrointestinal microbiota, essential for the digestion of arctic flora, which may include a large proportion of lichens during winter. Lichens are rich in plant secondary metabolites, which may affect members of the gut microbial consortium, such as the methane-producing methanogenic archaea. Little is known about the effect of lichen consumption on the rumen and cecum microbiotas and how this may affect methanogenesis in reindeer. Here, we examined the effects of dietary lichens on the reindeer gut microbiota, especially methanogens. Samples from the rumen and cecum were collected from two groups of reindeer, fed either lichens (Ld: n = 4), or a standard pelleted feed (Pd: n = 3). Microbial densities (methanogens, bacteria and protozoa) were quantified using quantitative real-time PCR and methanogen and bacterial diversities were determined by 454 pyrosequencing of the 16S rRNA genes.

In general, the density of methanogens were not significantly affected (p>0.05) by the intake of lichens. Methanobrevibacter constituted the main archaeal genus (>95% of reads), with Mbr. thaueri CW as the dominant species in both groups of reindeer. Bacteria belonging to the uncharacterized Ruminococcaceae and the genus Prevotella were the dominant phylotypes in the rumen and cecum, in both diets (ranging between 16–38% total sequences). Bacteria belonging to the genus Ruminococcus (3.5% to 0.6%; p = 0.001) and uncharacterized phylotypes within the order Bacteroidales (8.4% to 1.3%; p = 0.027), were significantly decreased in the rumen of lichen-fed reindeer, but not in the cecum (p = 0.2 and p = 0.087, respectively). UniFrac-based analyses showed archaeal and bacterial libraries were significantly different between diets, in both the cecum and the rumen (vegan::Adonis: pseudo-F<0.05). Based upon previous literature, we suggest that the altered methanogen and bacterial profiles may account for expected lower methane emissions from lichen-fed reindeer.”