Mutant Name: pmr4
| Gene Name | PMR4 |
| Protein Name | callose synthase |
| Mutagen | EMS |
| Category | forward genetics |
| Organism | Arabidopsis thaliana |
| Ecotype | Col |
| Donor | |
| General Description |
1.The pmr4 mutants develop at the same rate as wild-type and do not outwardly appear to be stressed. 2.pmr4 mutants is resistant to the powdery mildew Erysiphe cichoracearum and other biotrophic pathogens (E. orontii and Peronospora parasitica), and resistance appears to act after the pathogen has penetrated the plant cell wall Also, pmr4 produces dramatically less callose in response to powdery mildew infection or wounding. 3.This resistance was due to mutation of a callose synthase(GSL5 = CalS12), resulting in a loss of the induced callose response. 4.Direct DNA sequencing revealed a single base substitution (GA) in genomic DNA of pmr4-1 corresponding to position 2060 in the deduced coding sequence of the GSL5 gene. |
| Organ Specificity | |
| Impact on Wall | No constitutive changes in the cell walls were detected by Fourier transform infrared spectrometry when wild-type and pmr4-1 plants were compared. |
| Impact on Sugar Composition | infection and wound callose were missing from pmr4 plants. |
| Reference |
1. Vogel J, Somerville S. Isolation and characterization of powdery mildew-resistant Arabidopsis mutants. Proc Natl Acad Sci U S A. 2000 Feb 15;97(4):1897-902. 2. Nishimura MT, Stein M, Hou BH, Vogel JP, Edwards H, Somerville SC. Loss of a callose synthase results in salicylic acid-dependent disease resistance. Science. 2003 Aug 15;301(5635):969-72. |