A temperature-sensitive allele of a putative mRNA splicing helicase down-regulates many cell wall genes and causes radial swelling in Arabidopsis thaliana

• DOI: 10.1007/s11103-016-0428-0
• Publication Date: 2016-03-23T08:51:18Z
• Authors: Paul A. Howles; Leigh K. Gebbie; David A. Collings; Arvind Varsani; Ronan C. Broad; Stephen Ohms; Rosemary J. Birch; Ann H. Cork; Tony Arioli; Richard E. Willia...
• Keywords: 0301 basic medicine; RNA helicase; Arabidopsis thaliana; RNA Splicing; Arabidopsis; Down-Regulation; MRNA splicing; mRNA splicing; Cell expansion; 03 medical and health sciences; 1311 Genetics; Cell Wall; Gene Expression Regulation, Plant; 1110 Plant Science; 1102 Agronomy and Crop Science; RNA, Messenger; Alleles; 580; Arabidopsis Proteins; Cell wall; Temperature; Radial swelling; Mutation; Arabidopsisthaliana; RNA Helicases

The putative RNA helicase encoded by the Arabidopsis gene At1g32490 is a homolog of the yeast splicing RNA helicases Prp2 and Prp22. We isolated a temperature-sensitive allele (rsw12) of the gene in a screen for root radial swelling mutants. Plants containing this allele grown at the restrictive temperature showed weak radial swelling, were stunted with reduced root elongation, and contained reduced levels of cellulose. The role of the protein was further explored by microarray analysis. By using both fold change cutoffs and a weighted gene coexpression network analysis (WGCNA) to investigate coexpression of genes, we found that the radial swelling phenotype was not linked to genes usually associated with primary cell wall biosynthesis. Instead, the mutation has strong effects on expression of secondary cell wall related genes. Many genes potentially associated with secondary walls were present in the most significant WGCNA module, as were genes coding for arabinogalactans and proteins with GPI anchors. The proportion of up-regulated genes that possess introns in rsw12 was above that expected if splicing was unrelated to the activity of the RNA helicase, suggesting that the helicase does indeed play a role in splicing in Arabidopsis. The phenotype may be due to a change in the expression of one or more genes coding for cell wall proteins.