Secondary Cell Wall Thickening

Establishing an integrated network model for secondary wall thickening in anther development.

Secondary plant cell wall thickening is vital for many aspects of plant growth, typically for the production of mechanical tissues for water transport and support, but is also critical when other aspects of mechanical force are required, for example anther dehiscence. Secondary cell walls are composed of cellulose, hemicellulose and lignin. Advances have been made towards understanding the biosynthesis of these wall components, however little is known about the factors that control these pathways. Such regulatory networks tend to initiate the biosynthesis of multiple wall components, dissecting these regulatory networks may permit the separation of these pathways with the future goal of controlling specific components of the cell wall matrix in isolation from other components. Understanding such processes is vital for the manipulation of secondary thickening for modification of wood quality, biofuels, but also for the manipulation of processes requiring mechanical forces, for example anther dehiscence and the control of male fertility for hybrid development and control of gene flow.

Secondary thickening occurs in the anther endothecium and is vital for the physical forces needed for anther opening, as demonstrated by our Arabidopsis male sterile mutant myb26 which produces normal pollen but is male sterile because the pollen is not released. Over-expression of MYB26 switches on ectopic secondary thickening by regulating expression of a number of genes, involved in general secondary thickening pathways. Systems biology approaches, combining the expertise of mathematicians and biologists are being used to develop and test the regulatory network for MYB26 and how it relates to conserved pathways for secondary thickening in other tissues.