In this work, we look to confirm experimentally in the MYB46-VND7-NST1 network that we predicted by bioinformatic analysis of MYB46 binding site occurrence. We therefore analyzed the genetic circuits involving MYB46 and the upstream NAC-domain master regulators VND7 and NST1 in Populus and Arabidopsis by establishing whether MYB46 transactivates itself and the named upstream regulators. The promoters of MYB46, VND7 and NST1 are isolated by PCR amplification from Populus and Arabidopsis genomic DNA and cloned using overlap extension PCR. We then analyzed their transactivation by transiently expressed MYB46. We showed circuits of autoregulation and positive feedback involving MYB46 and NST1 in Populus that are absent in Arabidopsis. The significance of our results is discussed.

The objective of the project is to characterize and compare the gene regulatory networks regulating wood formation in Populus and Arabidopsis.