PI: Rishikesh P. Bhalerao

Staff: Jaesung Oh, postdoc; Delphine Gendre, postdoc

Background

During the course of secondary xylem development, cell division, expansion, secondary wall formation and cell death occur in a sequential manner. This temporal and spatial separation of key developmental events provides the opportunity to isolate secondary xylem cells and investigate processes that are specifically linked to each of these developmental events. Using this strategy gene expression linked preferentially with cell expansion in secondary xylem cells was identified in model plant poplar. The next step would be to characterize the function of these genes so as to identify key regulators of expansion and elongation in secondary xylem. However, several of the genes preferentially expressed in expanding xylem cells have no function that can be deduced from sequence alone. Therefore an alternative strategy was pursued by firstly identifying Arabidopsis homologs of poplar genes followed by reverse genetics approach to understand the role of these genes in Arabidopsis and subsequently in poplar. One such gene ELD1 encodes a protein involved in vesicular trafficking and mutations in ELD1 result in severe elongation defects in Arabidopsis. Overall this indicates that the strategy of using expression data from poplar to identify candidate genes involved in cell expansion and elongation is useful.

Aims

We have now identified interacting partners of ELD1 and these appear to be proteins that interact with the RAB like GTPases. The aim of this project is to characterize the ELD1 interacting proteins and also identify which RAB like GTPases could be involved in cell elongation in Arabidopsis and then express these specifically in secondary xylem cells to modulate their elongation in poplar and Arabidopsis. Once these plants are generated their phenotyping will be done in collaboration with other partners of FuncFiber at UPSC.