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Host mediated microbiome engineering for drought resistance in grasses

Michael Jochum: Texas A&M University


<div>Rhizosphere microbial communities (rhizobiomes) impact plant growth and response to various stress. The goal of the study is to select a rhizobiome associated with alleviation of drought stress in the plant, using a multi-generation experiment known as host mediated microbiome engineering (HMME). Wheat seedlings were grown in bermudagrass rhizosphere composites collected from arid environments in west Texas, and exposed to a water deficiency. At the point in time when 90% of wheat seedlings exhibited drought symptoms, we selected rhizobiomes from the top 10% of the seedlings with delayed symptoms. Selected rhizobiomes were subsequently inoculated into new sterile soil where the next generation of wheat was planted. The aforementioned process was repeated for seven generations. At the conclusion of the experiment, seedlings growing in selected rhizobiomes could delay the onset of drought by 5 days compared to those growing in the unselected first generation. Selected rhizobiomes also exhibited a 17% increase in water retention, 43% increase in relative water content, 60% increase in daily water use efficiency, 27% increase in root length, 14% increase in shoot length, 36% increase in root dry weight, 24% increase in root surface area, and 25% increase in root tips compared to the sterile control. This project demonstrates the ability to manipulate rhizobiomes to act in a synergistic manner as a probiotic treatment for growing grasses under drought conditions.</div>

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