Symbiotic Root-Endophytic Soil Microbes Improve Crop Productivity and Provide Environmental Benefits

Figure 1

Plant endophytic symbiotic microorganisms are able to enhance plant growth and development from seedlings to maturity, as evidenced by these examples from the use of Trichoderma with corn. (a) Ten-day-old seedlings of an inbred maize line (Mo17) grown from untreated seeds (upper row) or from seeds treated with T. afrohazianum (lower row). The differences in size that are seen in the seedlings persist in the mature plants. (b) Appearance of corn plants in a commercial trial in Minnesota. The plant on the right was grown from a seed treated with a commercial product containing T. afroharzianum and T. atroviride overtreated onto a standard chemical pesticide, while the plant on the left grew from a seed treated only with a chemical pesticide. Photo courtesy of Advanced Biological Marketing. (c) Both the organisms and their SAMPs can induce season-long changes that affect both shoots and roots. Shown are roots of mature corn plants grown from either seeds treated only with a chemical pesticide (left) or with similar seeds overtreated with the SAMP 1-octen-3-ol at picoliter quantities (right). The observed increase in root growth is distant both temporally (several months later) and spatially from the site of application of the SAMP. Photo courtesy of Advanced Biological Marketing. (d) Trichoderma strains increase rooting depth. Corn plants were grown in the field to maturity, and then, trenches were dug adjacent to them about 2.3 m deep. The soil faces next to the plants were treated with a power washer to expose root intercepts and were marked with map pins that show up as dots in the figure. At 25–75 cm below the soil surface, there were about twice as many roots from plants grown from Trichoderma-treated seeds as from untreated seeds [6].

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