Witchweed lurks in the heart of agricultural landscapes in Sub-Saharan Africa, siphoning nutrients from vital cereal crops, such as sorghum, maize, rice, and millet. This silent parasite, also known as Striga, causes crop losses of up to US$7 billion every year. Can microbes help save crops from parasitic weeds like Striga? A research team led by Francisco Dini-Andreote at Penn State aims to improve food security, soil health and climate change mitigation by manipulating microbial communities. Learn in-depth details about these projects in the webinar series “From field to food: Production and safety testing using molecular method” hosted by QIAGEN on 10 – 12 September. #MeetTheIndustry
Enlisting microbial allies
The bustling community of microbes nestled within plant roots is critical to a plant’s vitality and ecosystem health. “If you think about plants being healthy, and those plants also producing nutritional foods, microbes are essential players in that,” explains Penn State microbiologist and Assistant Professor of plant phytobiomes, Francisco Dini-Andreote. An unhealthy microbiome, on the other hand, can cause poor nutrient absorption, stunted growth and increased susceptibility to diseases. Additionally, such plants may fail to thrive in suboptimal soil conditions, ultimately decreasing crop yields and destabilizing the agroecosystem.
Microbiome balance in and around plants is influenced by many factors. Root hairs and root anatomical traits, for example the size and density of cortical cells, can affect the secretion of chemicals along the roots, says Dini-Andreote. This in turn affects the type of microorganisms that reside around those roots. Environmental conditions like soil type, soil pH, moisture levels and nutrient availability also impact the microbiota. By understanding such interactions, Dini-Andreote’s “main quest” is to harness the function of plant microbiomes to maximize the benefit of what they already do naturally, he says.
The witchweed problem
“Microbes provide nutrients to plants, but also protect them against biotic and abiotic stresses such as drought, nutrient deficiency and pathogens that we have in the systems and even parasitic plants,” says Francisco. One such parasitic plant is the aforementioned witchweed (aka, Striga).
As part of his post-doc research at the Netherlands Institute of Ecology (NIOO-KNAW), Dini-Andreote was involved in a collaborative project studying ways to use the microbiome to control the impact of Striga. The researchers learned that Striga seed germination is triggered by chemical molecules exudated by host plants, and that compounds produced by soil bacteria can disrupt this communication between the parasite and host plants.
After identifying these disruptive compounds, the researchers discovered precursor molecules that can be added to soil containing Striga seeds. Microbes in the soil metabolize this and suppress Striga seed germination, a technique that would neither require the use of toxic and expensive herbicides, nor directly manipulate soil microbial taxa.
Drought resistance and carbon storage
“If I want to manipulate 100 different microbial species over a given number of generations, I can do it. Microbiomes are kind of the ideal experimental units,” says Dini-Andeote. Thus, other ongoing projects include studying the root architecture of maize plants to make them more drought-tolerant and perhaps better able to sequester carbon for long-term soil carbon storage.
“In general, if roots are more lignified and angled in a more vertical manner, they can grow deeper into the soil,” says Dini-Andreote. One question he is trying to answer is whether these more lignified roots take longer to decompose in crop systems. “That may not seem important, but when you think of the extent of maize cultivation in the US, that can be a huge source of carbon sequestration.”
Tech makes research possible
Dini-Andreote has been using QIAGEN DNA and RNA soil extraction kits to study plant microbiomes since he began his scientific career. In his lab today, he uses DNeasy Plant Pro to prepare his samples for study, and QIAquick Gel Extraction Kits to purify them. He also uses qPCR assays to amplify, quantify and analyze microbial nucleic acids.
“QIAGEN soil extraction kits were a large part of the investment in starting up my lab,” he says. “The major advantages are the consistency of results and the ease of use of QIAGEN protocols.” Dini-Andreote has tried other kits in the past, but they often yielded inconsistent results. “I never had any issues with QIAGEN kits.”
Despite promising results thus far, the complexity of the microbiome poses a continuous challenge. “We’re talking about 10 to the ninth power of bacterial cells per gram of soil. That doesn’t even include fungi, protists, archaea and viruses,” he says.
Hear more about his research by registering for the webinar series “From field to food: Production and safety testing using molecular method” hosted by QIAGEN on 10 – 12 September .
About the author of this blog:
QAIGEN is a long-term partner of FEMS and have been Gold Sponsor of the FEMS Congress. They provide products and services that enable researchers to gain valuable insights from any biological sample – from basic research to clinical healthcare. They have kindly sponsored this FEMSmicroBlog post to help FEMS in its mission to support the microbiology community. If your company or organization would like to sponsor FEMS, please reach out to us to discuss how we can tailor our partnership.