Mutant Name: irx4
| Gene Name | IRX4 |
| Protein Name | cinnamoyl-CoA reductase |
| Mutagen | EMS |
| Category | forward genetics |
| Organism | Arabidopsis thaliana |
| Ecotype | Lb |
| Donor | |
| General Description | 1. irx4 plants grow more slowly than wild-type plants, are unable to retain an upright growth habit, exhibit altered leaf morphology. 2. irx4 plants have 50% less lignin than wild-type plants, while no significant changes in the cellulose or non-cellulose content. 3.irx4 mutation occurred in a cinnamoyl-CoA reductase (CCR) gene within a highly conserved intron splice site sequence of intron 2. 4.the mutation was identified as a G410 to A410 nucleotide substitution. 5.the irx4 mutation affects lignin biosinthesis. |
| Organ Specificity | stem |
| Impact on Wall | 1. The total lignin content of mature irx4 stems is less than 50% of the total content of wild-type stems. 2.Mutant cell walls appear to be hugely expanded, with the cytoplasm and vacuole contorted into abstract shapes in the centre of the cell due to the large area occupied by the walls. |
| Impact on Sugar Composition | 1.The total cellulose content in stems from differing developmental stages was slightly lower in irx4 plants compared to the wild type. 2.No significant differences were observed in the non-cellulosic cell-wall components . |
| Reference |
1. Jones L, Ennos AR, Turner SR. Cloning and characterization of irregular xylem4 (irx4): a severely lignin-deficient mutant of Arabidopsis. Plant J. 2001 Apr;26(2):205-16. 2.Patten AM, Cardenas CL, Cochrane FC, Laskar DD, Bedgar DL, Davin LB, Lewis NG. Reassessment of effects on lignification and vascular development in the irx4 Arabidopsis mutant. Phytochemistry. 2005 Sep;66(17):2092-107. |