| Abstrakt: |
Transcriptional regulation of secondary wall biosynthesis in Arabidopsis thalianahas been shown to be mediated by a group of secondary wall NAC master switches, including NST1, NST2, SND1 and VND1 to VND7. It has been shown that VND1 to VND7 regulate secondary wall biosynthesis in vessels, NST1 and NST2 function redundantly in anther endothecium, and SND1 and NST1 are required for secondary wall thickening in fibers of stems. However, it is unknown whether NST2 is involved in regulating secondary wall biosynthesis in fibers of stems. In this report, we demonstrated that similar to SND1, NST2 together with NST1were highly expressed in interfascicular fibers and xylary fibers but not in vessels of stems. Although simultaneous mutations of SND1and NST1have been shown to result in a significant impairment of secondary wall thickening in fibers, a small amount of secondary walls was deposited in fibers during the late stage of stem development. In contrast, simultaneous mutations of SND1, NST1and NST2led to a complete loss of secondary wall thickening in fibers. These results demonstrate that NST2 together with SND1 and NST1 regulate secondary wall biosynthesis in fibers of stems. |
