Early activation of cell wall strengthening-related gene transcription in cotton by a Verticillium dahliae elicitor

Differential expression of genes in cultured cotton cells and leaf disks that have been challenged with a purified elicitor from Verticillium dahliae, was investigated in order to identify genes involved in the early defense response of cotton. The mRNA differential display reverse transcriptase polymerase chain reaction was used to identify differentially expressed genes 5 h after application of 50 μg mL^{- 1} Verticillium dahliae elicitor. Sequence analysis of selected amplicons revealed homologies with genes involved in metabolism of carbohydrate precursors for cell wall synthesis. cDNAs identified that were up-regulated after elicitor treatment coded for homologs to a UDP-N-acetylglucosamine pyrophosphorylase-like protein, a glucosyltransferase-like protein, a beta-1,4-N-acetylglucosaminyltransferase, a cellulose synthase-like protein, a 3-deoxy-d-manno-octulosonic acid transferase-like protein and a hydroxyproline-rich glycoprotein. In addition, one cell wall-related cDNA that was down-regulated after elicitor treatment, coded for a proline-rich protein family member homolog. The differential expression of the cDNAs up-regulated after the Verticillium dahliae elicitor treatment was confirmed with reverse Northern dot blots. These results indicate that metabolic reprogramming through the enhanced synthesis of carbohydrate precursors accompanies the activation of de novo cell wall synthesis. As such it is important for the understanding of early defense related responses in cotton and for their biotechnological manipulation.