Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
® Scottish Crop Research Institute Root border cells in the rhizosphere A.G. Bengough, D. Cooke, B.S. Griffiths, S. Humphris, K. Killham1, O.G.G. Knox1, D.B. Standing1, S. Rodger2, V.E.C. Stubbs, T.Valentine, I.M. Young2 Scottish Crop Research Institute, Dundee; 1Department of Plant and Soil Science, University of Aberdeen; 2SIMBIOS Centre, University of Abertay Dundee. Border cell release into the rhizosphere • Root caps of most plant species are tipped with a fringe of border cells that can remain viable in the rhizosphere for several days Cultivar effects Rheology of root cap mucilage Mean no. border cells/root • There was an eight-fold variation in the rate of border cell release between maize cultivars. Rheological properties of the mucilage of the different cultivars affected border cell release. 700-1600 • Decapping decreased border cell numbers by an order of magnitude for 2-3 days until the cap regenerated. We tested the hypothesis that the rate of border cell release influences rhizosphere colonisation. Border cells within mucilage network 3200-3500 Border cells and rhizosphere carbon flow 6 Glucose exudation (ug/cell)x10-3 • Border cells actively take-up and release small quantities of glucose-C. • Root exudate contains much more bacteria-utilisable carbon than is released from border cells after they detach. 20 mM glucose 5 2 mM glucose 4 3 2 Border cell and associated mucilage 1 0 0 2 20 30 s.e.d. Time (h) Border cells influence colonization of the rhizosphere by (micro-) organisms Soil bacteria 7 -1 lo g C F U c m r o o t • Colonization of the root tip by Pseudomonas fluorescens (GFP-labelled) was increased in decapped roots • Concept that border cells and their associated mucilage act as a disposable sleeve around the root. Inta ct-loos e De ca p-compa ct Nematodes • Weak long-range attraction to border cells. 4 3 2 • Large and significant effects on movement at the local scale. Signal molecules involved? 1 0 Ne xt-to-tip Ne xt-to-s e e d Seed Root s e ction Tip Next-to-tip Next-to-seed Seed 10 mm Decapped root 0.025 0.020 Average speed (mm/s) Intact root cap Inta ct-compa ct 5 Tip • The border cell sleeve decreases root-soil friction and decreases root colonisation by biocontrol bacteria - with implications for biocontrol strategies in the field. De ca p-loos e 6 0.015 0.010 0.005 0.000 Treatment Nematodes + border cells Acknowledgements This work was funded by the BBSRC. SCRI receives grant-in-aid from SEERAD. Nematodes + beads Nematodes only