Evolution of specificity at the D14L signaling node for plant development and symbiosis
Lead Research Organisation:
University of Cambridge
Department Name: Plant Sciences
Abstract
Theme: Agriculture and Food Security
Unravel the function of D14L in the basal plant Marchantia paleacea. KAI2/D14L plays central roles in germination, seedling growth, and beneficial associations with arbuscular mycorrhizal (AM) fungi in Arabidopsis and rice, but the function of D14L in basal plants remains unknown.
Strigolactones (SLs) are plant hormones that regulate plant development and growth of AM fungi. Karrikins (KARs), on the other hand, are abiotic compounds found in smoke that stimulate seed germination of fire-chasing plants and influence seedling growth. The receptors for SLs and KARs, D14 and D14L/KAI2, are paralogs. SL-insensitive d14 mutants retain the ability to be colonized by AM fungi. In contrast, Rice D14L is indispensable for root-perception of AM fungi and for initiation of the symbiotic interaction. The common evolutionary origin of D14 and D14L explains the remarkable parallels between the SL and KAR signaling pathways, which culminate in a shared requirement for the F-box protein DWARF3(D3)/MORE AXILLARY GROWTH (MAX2). Orthologues of the KAR/KL-signaling components D14L, SMAX1 and D3 occur in all land plants, whereas the SL-signaling proteins D14 and D53 are absent from basal plants. Therefore, canonical SL signaling via D14-D3-D53 was an innovation of Embryophyta. Nonetheless SLs are found in basal plants, which indeed have developmental responses to exogenous SL analogs, possibly mediated via D14L. Plausibly, a D14L-mediated mechanism may have been important for early land plant development and AM symbiotic interactions. We will use our collective expertise to investigate the role of D14L in basal land plants and fire-adapted species.
(A) The basal liverworts include the genetically tractable Marchantiaceae. We will apply the CRISPR/Cas9 technology to the mycorrhizal species Marchantia paleacea to test the hypothesis that D14L is required for plant development and AM symbiosis in basal plants.
(B) To assess whether the role of D14L in symbiosis is conserved across the plant kingdom, genetic complementation of rice hebibaAOC with both M. paleacea and N. attenuata D14L genes will be performed. In non-mycorrhizal Arabidopsis introduction of Marchantia polymorpha D14L failed to complement kai2 developmental phenotypes. If similar observations were made for AM signaling in rice, M. paleacea D3 and SMAX1 will be introduced into hebibaAOC and crossed to the MpalD14L-expressing line to verify functional conservation. Similarly, D14L variants identified in Objective 2A to confer preference for KL-ligands will be examined for their ability to mediate symbiosis signaling by engineering equivalent substitutions of rice D14L.
ENWW:
- Transcriptome and proteome analysis of Mycorrhiza and Marchantia paleacea upon disruption of the gene D14L. These datasets will additionally be compared to transcriptomics/proteomics data collected from cereal species.
- Assessment of mycorrhizal colonization of M. paleacea via biological imaging and statistical analysis of the quantitative traits assessed.
Unravel the function of D14L in the basal plant Marchantia paleacea. KAI2/D14L plays central roles in germination, seedling growth, and beneficial associations with arbuscular mycorrhizal (AM) fungi in Arabidopsis and rice, but the function of D14L in basal plants remains unknown.
Strigolactones (SLs) are plant hormones that regulate plant development and growth of AM fungi. Karrikins (KARs), on the other hand, are abiotic compounds found in smoke that stimulate seed germination of fire-chasing plants and influence seedling growth. The receptors for SLs and KARs, D14 and D14L/KAI2, are paralogs. SL-insensitive d14 mutants retain the ability to be colonized by AM fungi. In contrast, Rice D14L is indispensable for root-perception of AM fungi and for initiation of the symbiotic interaction. The common evolutionary origin of D14 and D14L explains the remarkable parallels between the SL and KAR signaling pathways, which culminate in a shared requirement for the F-box protein DWARF3(D3)/MORE AXILLARY GROWTH (MAX2). Orthologues of the KAR/KL-signaling components D14L, SMAX1 and D3 occur in all land plants, whereas the SL-signaling proteins D14 and D53 are absent from basal plants. Therefore, canonical SL signaling via D14-D3-D53 was an innovation of Embryophyta. Nonetheless SLs are found in basal plants, which indeed have developmental responses to exogenous SL analogs, possibly mediated via D14L. Plausibly, a D14L-mediated mechanism may have been important for early land plant development and AM symbiotic interactions. We will use our collective expertise to investigate the role of D14L in basal land plants and fire-adapted species.
(A) The basal liverworts include the genetically tractable Marchantiaceae. We will apply the CRISPR/Cas9 technology to the mycorrhizal species Marchantia paleacea to test the hypothesis that D14L is required for plant development and AM symbiosis in basal plants.
(B) To assess whether the role of D14L in symbiosis is conserved across the plant kingdom, genetic complementation of rice hebibaAOC with both M. paleacea and N. attenuata D14L genes will be performed. In non-mycorrhizal Arabidopsis introduction of Marchantia polymorpha D14L failed to complement kai2 developmental phenotypes. If similar observations were made for AM signaling in rice, M. paleacea D3 and SMAX1 will be introduced into hebibaAOC and crossed to the MpalD14L-expressing line to verify functional conservation. Similarly, D14L variants identified in Objective 2A to confer preference for KL-ligands will be examined for their ability to mediate symbiosis signaling by engineering equivalent substitutions of rice D14L.
ENWW:
- Transcriptome and proteome analysis of Mycorrhiza and Marchantia paleacea upon disruption of the gene D14L. These datasets will additionally be compared to transcriptomics/proteomics data collected from cereal species.
- Assessment of mycorrhizal colonization of M. paleacea via biological imaging and statistical analysis of the quantitative traits assessed.
Organisations
People |
ORCID iD |
| Uta Paszkowski (Primary Supervisor) | |
| MARA SGROI (Student) |
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| BB/M011194/1 | 01/10/2015 | 31/03/2024 | |||
| 1804811 | Studentship | BB/M011194/1 | 01/10/2016 | 30/03/2021 | MARA SGROI |
| Description | I am studying a symbiosis (arbuscular mycorrhiza) between land plants and soil fungi, which is extremely whidespread in nature: more than 80% of all land plants engage in it, and it benefits them by helping them grow bigger, stronger and more resilient to environmental stresses. My interest is in the evolutionary conservation of this symbiosis: it evolved 400 million years ago, at the same time as plants colonized land. Through my research we discovered that the genes and pathways that regulare this symbiosis in plants are conserved in early diverging land plants (liverworts) that engage in this symbiosis, meaning that the molecular machinery that controls this symbiosis evolved once only more than 400 million years ago, before liverworts evolved away from the other land plants, and is not the product of multiple rounds of convergent evolution. This machinery has been conserved by evolution for 400 million years. |
| Exploitation Route | The outcomes of this funding are already being explored for application by a grant from the Bill and Melinda Gates foundation. The final aim of this project is to allow sub-saharan farmers to grow Maize without the need for additional nitrogen fertilizers, which many of them are not able to afford due to the relative high cost of fertilizers compared to their annual income. The project aims to engineer crops to fix nitrogen from the air by adding specific genes in Maize, these genes control both the arbuscular mycorrhiza simbiosis and nodulation (symbiosis with soil nitrogen-fixing bacteria) and are proven in my analysis to be conserved across land plants. |
| Sectors | Agriculture, Food and Drink |
| Description | 100th Natural History Festival |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | Regional |
| Primary Audience | Public/other audiences |
| Results and Impact | Every year the Cambridge Natural History Society holds an exhibition for students and the general public. The aim of the exhibition is to share our passion for the natural world, and stands range from research outreach, to local NGOs to private collections. In 2019 I organised a stand to participate to the festival presenting my PhD and my laboratory's work to engage the public on our research. The interest was great, and we won the price for best stand. |
| Year(s) Of Engagement Activity | Pre-2006,2006,2007,2008,2009,2010,2011,2012,2013,2014,2015,2016,2017,2018,2019,2020 |
| URL | http://www.cnhs.org.uk/ |
| Description | Cambridge Science Festival |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | Regional |
| Primary Audience | Public/other audiences |
| Results and Impact | Cambridge University organises a Science Festival every year to engage the general public with research activities going on at the university. The audience is very broad, from toddlers to 80+ elderly. I partecipated to the festivals two years, once organising the Cambridge Food Security Forum stand, and the other the Cereal Symbiosis stand, both of them on behalf of the plant sciences department and relating to my research. I organised the activities on the stand and I volunteered on the day of the event to explain our research effort to the public. On the day, around 1500 people entered the marquee where our stand was exhibiting our research. |
| Year(s) Of Engagement Activity | 2018,2019 |
| URL | https://www.sciencefestival.cam.ac.uk/ |