Mutations of the secondary cell wall

It has not been possible to isolate a number of crucial enzymes involved in plant cell wall synthesis. Recent progress in identifying some of these st eps has been overcome by the isolation of mutants defective in various aspe cts of cell wall synthesis and the use of these mutants to identify the cor responding genes. Secondary cell walls offer numerous advantages for geneti c analysis of plant cell walls. It is possible to recover very severe mutan ts since the plants remain viable. In addition, although variation in secon dary cell wall composition occurs between different species and between dif ferent cell types, the composition of the walls is relatively simple compar ed to primary cell walls. Despite these advantages, relatively few secondar y cell wall mutations have been described to date. The only secondary cell wall mutations characterised to date, in which the basis of the abnormality is known, have defects in either the control of secondary cell wall deposi tion or secondary cell wall cellulose or lignin biosynthesis. These mutants have, however, provided essential information on secondary cell wall biosy nthesis.