Abstract
Flagellin, a main component of a bacterial flagellum, purified from rice-incompatible strain, N1141, of Acidovorax avenae specifically induces defense responses, such as hypersensitive cell death and defense-related genes. In this study, we analyzed the flagellin perception system in rice. Cultured rice cells did not respond to flg22, an elicitor-active synthetic peptide in Arabidopsis and tomato comprising the conserved 22 amino acids within the N-terminal part of flagellin, and a peptide corresponding to flg22 within flagellin of A. avenae. On the other hand, C-terminal recombinant flagellin fragment induced reactive oxygen species and defense-related gene in cultured rice cells. Furthermore, binding experiment for flagellin in rice microsomal membrane revealed the existence of a 45 kDa flagellin binding protein, which is apparently different from 115 kDa flg22 binding protein in tomato. These results suggest that rice has the different flagellin perception system from Arabidopsis and tomato.
