PYL13 Protein Engineering for Drought Tolerance
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Solution Overview
Problem
Current technologies lack effective methods for enhancing drought tolerance in plants, as existing approaches often require elevated abscisic acid (ABA) levels to induce stress-tolerance genes, which may not be practical for pre-conditioning plants before stress conditions arise.
Innovation Solution
Development of transgenic plants over-expressing a recombinant DNA construct encoding a polypeptide at least 95% identical to the PYL13 protein, which interacts with clade A PP2Cs in an ABA-independent manner, thereby inhibiting their activity and promoting drought tolerance without the need for elevated ABA levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plants are pre-conditioned with elevated ABA levels before stress conditions, then stress-tolerance genes can be activated in advance, but this approach is not practical for pre-conditioning plants before stress arises
Solution Approach 1:
The patent applies preliminary action by introducing a constitutively active PYL13 protein that continuously inhibits PP2C phosphatases, thereby maintaining baseline activation of stress-tolerance genes without requiring actual stress conditions or elevated ABA levels. This allows plants to be pre-prepared for drought stress through genetic modification rather than temporary chemical treatment.
Solution Approach 2:
The PYL13 protein serves itself by constitutively binding to and inhibiting PP2C phosphatases, creating a self-sustaining activation mechanism that does not require external ABA signaling. The system becomes autonomous, continuously promoting stress-tolerance gene expression without needing environmental triggers or manual intervention.
2Reliability
If PYL13 interacts with clade A PP2Cs in an ABA-independent manner, then drought tolerance can be promoted without elevated ABA levels, but the interaction mechanism differs from conventional ABA-dependent pathways
Solution Approach 1:
The patent extracts the ABA-dependent signaling step from the pathway by using PYL13's unique ability to bind and inhibit PP2C phosphatases independently of ABA. This removes the requirement for ABA presence, simplifying the overall signaling mechanism while maintaining drought tolerance functionality.
Solution Approach 2:
The patent changes the key parameter of ABA dependency to ABA independence in the PYL13-PP2C interaction. By altering the binding condition from ABA-required to ABA-independent, the system achieves drought tolerance through a modified parameter state, allowing continuous inhibition of PP2Cs without hormonal regulation.
3Reliability
If stress-tolerance genes are activated through ABA-dependent pathways, then genes are expressed in response to actual stress, but this requires elevated ABA levels that may not be practical for pre-conditioning
Solution Approach 1:
The constitutively active PYL13 protein performs preliminary action by continuously inhibiting PP2C phosphatases before actual drought stress occurs. This maintains baseline activation of stress-tolerance genes in advance, eliminating the need to wait for stress-induced ABA elevation while still achieving gene expression.
Solution Approach 2:
PYL13 acts as an intermediary between the goal of stress-tolerance gene activation and the constraint of avoiding elevated ABA levels. By serving as a constant inhibitor of PP2Cs, it mediates continuous gene activation without requiring the substance (ABA) that would otherwise be needed to trigger the response.
Data Source
AI summary
Embodiments of the present invention relate generally to drought tolerant transgenic plants and methods of creating the drought tolerant transgenic plants. In one embodiment, plants are transformed such that a PYL polypeptide is overexpressed in the plant. In an embodiment, the plant is transformed with a cassette or vector that comprises a polynucleotide encoding for one or more of the PYL polypeptides, which may be under the control of an inducible or constitutive promoter. In embodiments, overexpression of PYL13 results in plants having increased drought tolerance, such as a decreased transpiration rate, a decreased stomatal conductance, an increased photosynthetic rate, accelerated stress responsive gene expression, and increased water use efficiency, and/or an increased survival rate compared to a control plant. In some embodiments, other PYL proteins having the single point mutations identified in PYL13 are expressed in the plant.