School of Biological Sciences Seminar Series

Cytokinin: a hormone with many roles

Speaker

Professor Paula Jameson

Institute

University of Canterbury

Time & Place

Thu, 14 Mar 2019 14:00:00 NZDT in Rehua 226 Te Moana (Coppertop)

All are welcome

Abstract

In the early 1980’s, the cytokinins were declared to be “a plant hormone in search of a role”. In this talk, Paula will show that this is clearly not the case. She will take us through her research career in unravelling the role of these important compounds. She will start with her early research confirming the mobility of root-derived cytokinins, and the more recent research by her group showing that the cytokinins are involved in the homeostatic mechanism balancing uptake and assimilation of nitrogen with availability of carbohydrate.

Much of Paula’s recent research has been on crop seeds and she will introduce the importance of cytokinins as determinants of seed number and seed size. While cytokinins are intimately linked to cell division in cereals, in legumes they are implicated in enhancing sink activity. In double transgenic peas ectopically expressing both an amino acid transporter and a sucrose transporter, she showed elevated endogenous cytokinins in the seed coat, clearly indicating, again, the intimate relationship between cytokinin, nitrogen and carbohydrate.
Paula will also cover her team’s latest research on the gall-forming bacterium Rhodococcus fascians. Several gall-forming bacteria produce cytokinins. However, for many years the multiple shoots and leafy galls produced by R. fascians have been an enigma, because of the lack of elevated cytokinin in infected tissue. Both leaf surface and endophytic R. fascians produce cytokinins and induce plant transporter genes but only the endophytic strains affect plant morphology. Very recently Paula’s team confirmed that endophytic R. fascians produce a newly discovered methylated cytokinin. They suggest that these cytokinins interact with a family of plant sugar transporters (SWEETs) and cell wall invertases to induce multiple shoots in pea.
 
Introduced by Prof. Matthew Turnbull