The role of SND2 in the regulation of Arabidopsis fibre secondary cell wall formation

Background Transcription factors (TFs) play important roles in the regulation of secondary cell wall (SCW) biosynthesis in herbaceous and woody plants. In Arabidopsis, the onset of SCW deposition is initiated by a nexus of NAC, MYB, homeodomain and several other families of TFs, which function in a transcriptional network regulating SCW biosynthetic genes. NAC family members SND1/ NST1 and VND6/VND7 have been identified as functionally redundant master regulators of SCW formation in fibres and vessels, respectively [1,2]. Arabidopsis plants overexpressing SND2, an indirect target of fibre master regulator SND1, exhibited increased SCW thickness in inflorescence stem fibres, whilst dominant repression lines exhibited a decrease in fibre SCW thickness associated with a reduction in glucose and xylose cell wall sugar content [3]. The ability of SND2 to transactivate the CesA8 promoter [3] suggested that SND2 may regulate cellulose biosynthetic genes during fibre SCW formation. The evaluation of this hypothesis necessitates the identification of all downstream genes potentially regulated by SND2, and the analysis of SCW chemistry and morphology in overexpression lines. The aim of this ongoing study is to further elucidate the role of SND2 in fibre SCW formation through microarray analysis of overexpression lines and by independent confirmation of the effect of SND2 overexpression on fibre SCW chemistry and morphology in Arabidopsis plants.