KAI2 regulates root and root hair development by modulating auxin distribution (bioRxiv)

To optimize growth, plant development is regulated by environmental information. Root morphology is adaptable to stimuli due to a network of phytohormone signalling pathways. Here Villaecija et al. studied the roles of strigolactones (SL) and karrikins (KL) signalling in controlling root and root hair development in Arabidopsis. SLs and KLs are similar in size and structure, and both act through the same Fbox protein MAX2. By using mutants affected in SL biosynthesis and SL and KL receptors (D14 and KAI2) this study shows, conversely to earlier studies, that SL signalling has minor effects while KL signalling is a key regulator of root hair development. KL regulates auxin distribution through the concentration of the protein PIN7 in the root tip. Furthermore, this study suggest KL signalling alone suppresses root skewing and modulates root straightness, growth direction and diameter. This work helps to understand important signalling pathways which may lead to plant development and tune growth for agriculture improvement. (Summary by Ana Valladares) bioRxiv https://doi.org/10.1101/539734