As germination corresponds to the transition from a highly resistant seed to a particularly vulnerable seedling, there must be mechanisms to set up to block germination under conditions that are potentially fatal for the seedling.

The endosperm plays a significant role in the control of the germination by releasing the hormone abscisic acid (ABA) under unfavorable environmental conditions. ABA blocks the germination, keeping the embryo protected within the seed. Recent studies have shown a more surprising role for the endosperm. It indeed plays a major role in the establishment and development of the young seedling. However, how the endosperms regulate early seedling developments remains largely unknown. I therefore investigated the potential role of MYBs transcription factors specifically and highly expressed in the endosperm during the germination. I observed that myb33myb101 double mutants have shorter primary roots compared to WT. Moreover, I observed that myb33myb101 double mutants and myb33myb65myb101 triple mutants exhibit an increased cotyledons retention in seed coat after germination. The results suggest that two endospermic-MYBs, MYB33 and MYB101, redundantly regulate seedling root development and seedling cuticle formation. From RNA- seq data, I hypothesized that MYB33 and MYB101 regulate early seedling development through inducing expressions of endospermic signaling peptides including RGF7 and PSY1. Finally, I was able to identify dramatic changes in the myb33myb101 endosperm transcriptome, suggesting that MYB33 and MYB101 may be involved in the transcriptomic identity of endosperm tissue.