Microbe Plant Interactions
Microbe plant interactions are an ongoing, every changing encounter. This is a microscopic, symbiotic relationship unseen by the naked eye.
Here’s a great quote from Nature the international weekly journal of science.
Plant—microbe encounters can be friendly or hostile. Densely colonized soil contains beneficial mycorrhizal fungi and rhizobia, which associate with roots and provide plants with mineral nutrients and fixed nitrogen, respectively, in exchange for carbon.
For this post, we’ll only talk about the friendly interactions between microbes and plants. We’ll also include bacteria and the microscopic fungi, Trichoderma, into the discussion.
There are too many types on microbe plant friendly interactions to completely discuss here, but we’ll talk about a few of the main ones.
- Carbon root exudate by plants
- Nitrogen fixation by bacteria
- Phosphate solubilization by bacteria and fungi
- Auxin and other growth hormone production by bacteria and fungi
Plant exudate, or excrete, carbon compounds into the soil. These compounds serve to attract a variety of microorganisms. The microorganisms need the carbon for cellular components and to reproduce.
Nitrogen is needed by plants for both protein synthesis and for DNA and RNA synthesis. Atmospheric nitrogen is very abundant. The problem is that atmospheric nitrogen is not available to plants. Many bacteria, including Paenibacillus, are capable of taking atmospheric Nitrogen and incorporating the Nitrogen into their cell. This process is called Nitrogen fixation. By use of this process, atmospheric nitrogen, otherwise unavailable to the plant, is now available. Nitrogen fixing bacteria are an integral part of the Nitrogen cycle.
Phosphate is required by plant cells for both DNA synthesis and energy transport. The important chemicals ATP and ADP both require phosphate. Both bacteria and Trichoderma solubilize phosphate and make it available to the plant. The phosphate cycle, while not as well know as the nitrogen or carbon cycles, is vital to the plants survival.
Auxins are growth hormones that stimulate plant growth, particularly root growth. More auxins cause plants to have healthier, better developed root systems. Better root systems, of course, means a healthier, more productive plant. Several bacterial species and Trichoderma fungi produce auxins and a myriad of other plant growth hormones.
Microbe plant interactions are diverse and complex. It is safe to say, that without beneficial soil microbes, plants would have difficulty growing to their full potential.