The mechanistic basis of PIN protein localisation
Lead Research Organisation:
University of Cambridge
Department Name: Plant Sciences
Abstract
The project is separated into 3 main sections.
Firstly, using hormone treatments and confocal microscopy to investigate differential PIN1, 3, 4 & 7 localisation to the plasma membrane in response to auxin and cytokinin in Arabidopsis stems. The aim being to determine whether PINs are allocated to the membrane in response to auxin flux or by an auxin concentration-based mechanism and whether this differs between PINs. I have already made significant inroads with this project, finding some interesting age-based differences and different cytokinin responses between PINs.
Secondly, I am investigating the behaviour of other families of PIN proteins which are absent from Arabidopsis. Namely, SoPIN1and PIN1b of Brachypodium, which have been shown to have different expression patterns and functions to Arabidopsis PIN1. I am using Arabidopsis lines transformed with SoPIN1-citrine & PIN1b-citrine driven by the AtPIN1 promoter. The goal being to determine the extent to which SoPIN1 & PIN1b are able to complement the function of AtPIN1 with regard to branching behaviour as well as determine whether their localisation is responsive to cytokinin and strigolactone.
Thirdly, I am performing domain swaps between the hydrophilic loop (HL) region of PIN1 and PIN3. This has been shown to be a key region of regulation for PIN localisation, PIN1 responds to strigolactone by being removed from the plasma membrane, whilst PIN3 does not. Swaps performed by a previous PhD student indicate that placing parts of the PIN1 HL into PIN3 is able to alter its behaviour and confer responsiveness to strigolactone. From this we identified a particular region as likely being important in conferring strigolactone responsiveness and I have performed the reverse swap, placing this region of the PIN3 HL into PIN1. I will then be able to perform a number of experiments using plants expressing this chimeric protein in order to determine firstly whether swapping this region abolishes PIN1 strigolactone responses and if so, how a lack of PIN strigolactone responsiveness impacts branching.
The over-arching aim of this project is to establish a system whereby we are able to create plants in which the PINs present are insensitive to a particular hormone (e.g. strigolactone and cytokinin) such that we can assess the impact this has on branching phenomena. This will enable us to parse the role of cytokinin and strigolactone in modulating axillary meristem activation.
Firstly, using hormone treatments and confocal microscopy to investigate differential PIN1, 3, 4 & 7 localisation to the plasma membrane in response to auxin and cytokinin in Arabidopsis stems. The aim being to determine whether PINs are allocated to the membrane in response to auxin flux or by an auxin concentration-based mechanism and whether this differs between PINs. I have already made significant inroads with this project, finding some interesting age-based differences and different cytokinin responses between PINs.
Secondly, I am investigating the behaviour of other families of PIN proteins which are absent from Arabidopsis. Namely, SoPIN1and PIN1b of Brachypodium, which have been shown to have different expression patterns and functions to Arabidopsis PIN1. I am using Arabidopsis lines transformed with SoPIN1-citrine & PIN1b-citrine driven by the AtPIN1 promoter. The goal being to determine the extent to which SoPIN1 & PIN1b are able to complement the function of AtPIN1 with regard to branching behaviour as well as determine whether their localisation is responsive to cytokinin and strigolactone.
Thirdly, I am performing domain swaps between the hydrophilic loop (HL) region of PIN1 and PIN3. This has been shown to be a key region of regulation for PIN localisation, PIN1 responds to strigolactone by being removed from the plasma membrane, whilst PIN3 does not. Swaps performed by a previous PhD student indicate that placing parts of the PIN1 HL into PIN3 is able to alter its behaviour and confer responsiveness to strigolactone. From this we identified a particular region as likely being important in conferring strigolactone responsiveness and I have performed the reverse swap, placing this region of the PIN3 HL into PIN1. I will then be able to perform a number of experiments using plants expressing this chimeric protein in order to determine firstly whether swapping this region abolishes PIN1 strigolactone responses and if so, how a lack of PIN strigolactone responsiveness impacts branching.
The over-arching aim of this project is to establish a system whereby we are able to create plants in which the PINs present are insensitive to a particular hormone (e.g. strigolactone and cytokinin) such that we can assess the impact this has on branching phenomena. This will enable us to parse the role of cytokinin and strigolactone in modulating axillary meristem activation.
Organisations
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| BB/M011194/1 | 01/10/2015 | 31/03/2024 | |||
| 1943121 | Studentship | BB/M011194/1 | 01/10/2017 | 30/09/2021 | Anthony Bridgen |
| Description | I've noted that PINs are not able to directly sense auxin flux That PIN1 behaves differently at different developmental stages |
| Exploitation Route | Could use it to try and manipulate shoot branching phenotypes which might affect yield |
| Sectors | Agriculture, Food and Drink,Environment |