Effects on genome constitution and novel cell wall formation caused by the addition of 5RS rye chromosome to common wheat

Abstract

The cytological instability of common wheat-rye addition lines was investigated in the present study. The chromosome numbers of almost all addition lines were considerably stable, but those of CS+5R were very variable. The rye chromosome added in this line was found to be much shorter than expected. Fluorescent in situ hybridization with 5S rDNA and the centromere-specific probes clearly revealed that the short rye chromosome contains only a short arm of chromosome 5R (5RS). In this line, chromosome numbers of both 5RS and common wheat were changeable. The chromosome numbers ranged from 2n=36 to 2n=44 in the cells carrying two 5RS, and ranged from 2n=31 to 2n=44 in one 5RS cells. In addition to the chromosome instability, the multicells wrapped in a sac-like structure were frequently observed in the root meristematic tissues of CS+5RS after the enzyme treatment for chromosome preparation. Genomic in situ hybridization with rye DNA as a probe showed that all cells in sacs investigated were at the interphase stage and contained one or two 5RS chromosomes. An electron microscopic analysis revealed that the cells of CS+5RS, particularly in sacs, have abnormal (irregular and curved) cell walls. These results indicate that 5RS has (a) specific factor(s) influencing the cell wall development as well as the genome stability. © 2008 Institute of Botany, the Chinese Academy of Sciences.