Paszkowski Group: Seeing nutrition: How does cell-specific regulation of SMAX1 enable productive plant-fungal cooperation?
Supervisor
Uta Paszkowski
Brief summary
Most land plants, including the critical calorie crop rice, derive much of their mineral needs from symbiotic associations with arbuscular mycorrhizal (AM) fungi. Specialised fungal structures, that form and collapse inside root cortex cells within a few days, mediate the delivery of soil minerals to the plant. Engagement of rice with these fungi involves the negative regulator SMAX1 as a key signalling hub1,2. Via degradation of this protein, multiple signals of plant nutrient status are integrated into a decision to facilitate cell penetration by the fungus. However, recent evidence suggests SMAX1 also plays a role in cortex cells hosting the arbuscules as it enhanced stabilisation coincides with maturation of arbuscules. This has led to the hypothesis that SMAX1 might be involved with regulating arbuscule life-span and perhaps initiate the senescence of arbuscules in response to elevated cellular mineral levels.
Importance of Research
This project has the potential to close the gap in understanding about the determinants of arbuscule life-span and functioning. We hope that these findings will help us better understand the AM symbiosis, and aid engineering efforts to increase the benefit our crop plants gain from this interaction, reducing demand for and consequences of fertiliser application.
Project Summary
This project will examine the function(s) of SMAX1 in the cortex/arbuscule interaction using a mix of plant mutant and nutrient treatment approaches combing with confocal time-course imaging of these exchange structures with fluorescent protein biosensors for SMAX1 stability3.
What will the successful applicant do?
You will attempt to discover how the plant regulates the degradation of SMAX1 in these cells, what nutrient or fungal derived signal triggers this, as well as the impact on the benefit the plant gains from the AM symbiosis.