Missouri resident Thomas “Tom” Brutnell is an agricultural biotech executive who helps guide Gateway Biotechnology, Inc., as vice president. One of Thomas Brutnell’s areas of in-depth knowledge is C4 photosynthesis and plant tissue culture and transformation.

A foundational technique of plant research, tissue culture provides a controlled environment that allows plants to be copied precisely or genetically altered. This is accomplished through taking an explant, or tiny piece of plant tissue, and culturing it under sterile conditions in an appropriate nutrient medium.

One critical aspect of this process is the fact that by manipulating growth hormones (e.g. cytokinin and auxin), cells which were once specified to develop into a specific tissue can be de-differentiated or made to behave more like stem cells. Thus, a piece of a root or leaf can be used to create a mass known as a callus that is undifferentiated at a cellular level.

With the ideal growing condition for an explant in place, hormones can then be added and the plant induced to rapidly generate new roots or shoots, simply by altering the ratio of the plant hormones. Once shoots and roots have formed, a plantlet can be further divided to deliver numerous new plantlets that may be transferred to a soil medium and grown in the regular way. After having been regenerated from tissue culture, these plants possess identical genetics to their originating cell. This can help ensure the uniformity and validity of tests across various plant specimens. For instance, sugarcane is routinely vegetatively propagated through tissue culture producing hundreds or thousands of genetically identical siblings for planting.