The modular approach

Transgenic plants expressing the GUSPlus in vivo reporter enzyme can be assayed with GUS substrates to give rise to a blue colour in the plant tissue

In a systems approach to get the engineered bioindicator concept working in a globally important cropping system to address real local constraints, we envision a biosentinel or bioindicator with the following modules that can be recombined according to local preference:

  • An indicator species that is suitable for the cultural system, the soil, the climate, etc. This can be the crop of interest or, even better, plants that are outside the food chain but grown alongside the crop. With the availability of CAMBIA’s TransBacter project, we hope that new protocols will be co-developed among various communities to facilitate the transformation of diverse potential bioindicator plants.  Most of the previous research has been done on Arabidopsis using Agrobacterium methods encumbered by a variety of patents that prevent practical use outside companies that have closely held licenses.  CAMBIA, via a BiOS license, is also offering the TransBacter technology to encourage participants to use the method to obviate these obstructive licensing practices for bioindicators for public good.
  • A receptor for the signal, e.g. in the roots of a plant, if we are after a bioindicator for a nutrient deficiency. For this, each community may decide what sort of bioindicators they need; we’re looking for input in our Forum or by E-mail.
  • A transduction of the signal from the receptor site via a responsive system.
  • Translation of the signal into something that can be observed, such as wilting, an odor, or a visible or infra-red color change mediated by a GUS gene product, an anthocyanin gene or similar genes, expressed in a part of the plant that is observable. (Ideally, the signal should be quantifiable, expressed in proportion to the level of the physiological parameter being detected. In the best mode, two signals could be used, which can be compared against each other for high accuracy.  Amplification of the signal could potentially occur at any point in this chain, for example at the signal transduction step via a transactivation cassette.)  In this project, CAMBIA is offering highly distinctive visual markersand transactivation cassettes to help move this technology into a real working model.
  • A detection system for humans (an inventive device, or one of the five senses), ideally nondestructive, inexpensive or costless to use, reliable under field conditions and requires no instrumentation.
  • Ways to act on the information, e.g. an input, intercropping or other timely, locally appropriate actions, in the farmer’s best judgment.

An advantage of the systems approach is that it can bring non-transgenic or post-transgenic modules to service for empowering particular actions by farmers and breeders. Such actions will more likely lead to adoption and further innovation of the technology as compared to the provision of a complete bioindicator prototype.

Realizing that there may be even better visual markers and promoters out there, we hope this provides impetus for talented groups that may identify and/or provide such useful markers for the bioindicators project as a public good. Do you know of any that might be really useful for this purpose?   If so, comment on this page.

Modules may be patented, but the capability to use them for research and commercial purposes by all those interested to use and improve them for public good can still be shared via a BiOS license.