Novel agrochemical control of stress signalling pathways for enhanced stress tolerance

Scientists at ANU have developed a novel method to regulate key plant stress responses such as stomatal closure using an agrochemical strategy. Delivery of the technology could be via GM or non-GM approaches.


Two strategies to enhance drought tolerance are possible and both involve inhibition of the SAL1 enzyme leading to accumulation of its substrate, PAP, a stress signal in plants. The first is a chemical approach using existing agrochemicals or new chemistries and the second is the application of PAP analogues.  ANU researchers have developed a potentially superior approach in the development of stress-tolerant crops.


The research team at ANU has developed a novel method to regulate key plant stress responses, including response to drought, using an agrochemical strategy via the application of "yield rescue herbicides".

The SAL1 enzyme is directly regulated by oxidative conditions and its ability to degrade PAP in plants can be controlled by the application of oxidative chemicals. The research team has been investigating how activity of the SAL1 enzyme can be controlled. The team studied the role of PAP in drought stress tolerance, and discovered that it can induce closure of stomata when accumulated in plants or when applied as an agrochemical. When applied to plant leaves, PAP can induce similar signalling networks as those activated by the key plant stress hormone, abscisic acid (ABA).

Collectively, these findings indicate the potential to modulate stress tolerance in plants using agrochemicals which either decrease SAL1 activity, leading to PAP accumulation and stomatal closure, or via direct application of PAP analogues to achieve the latter outcome.

This approach, whether by using new or repurposed chemical inhibitors of SAL1 or PAP analogues, will work on all existing varieties of crop plants.  In addition, this "Yield Rescue Herbicide" approach may enable farmers to still obtain value from a crop that may otherwise have succumbed to drought or lost significant yield making harvesting uneconomical.

Costs will be significantly less than the development of new GM/nonGM varieties and the time to market will be reduced. If the approach involves repurposing existing herbicides, then the time to market and cost of development is further reduced.


  • Technology to improve drought tolerance in both monocot and dicots crop plants
  • Delivery via non-GM approaches possible
  • SAL1 crystal structure allows rational design of additional chemical inhibitors
  • SAL1 activity, PAP accumulation and drought tolerance can be manipulated via controlled application of industrial bioactive chemicals such as paraquat.
  • PAP analogues can be used to selectively alter stomatal closure.


ANU is seeking collaborations with agbiotechnology and seed companies with interests in improving drought tolerance in crop plants.

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