Abstract
Secondary walls are synthesized only in limited tissues such as stem, hypocotyl, anther and silique. We report here that NAC domain transcription factors, NST1, NST2 and NST3, are key regulators of secondary wall synthesis in plants. The nst1/nst2 double T-DNA tagged line showed indehiscent anther due to loss of secondary wall in anther endocecium, while nst1/nst3 double T-DNA tagged line showed complete loss of secondary walls in stem and hypocotyl. Furthermore, nst1 single tagged line showed loss of secondary wall in valve margin of silique and nst1/nst3 double tagged line showed it in valve endodermin as well as valve margin, resulting in indehiscent silique. On the contrary, ectopic expression of either the NST genes induced ectopic secondary wall synthesis in various above-ground organs. We concluded that NST transcription factors are master regulators of secondary wall synthesis in plant and act redundantly in various organs.
