CONSTITUTIVE TRIPLE RESPONSE 1 and PIN2 coordinately regulate indeterminate root growth (Plant Sci)

Méndez-Bravo et al. explored the mechanism for the dramatic phenotype of the ctr1 mutant (CONSTITUTIVE TRIPLE RESPONSE 1), which inhibits both cell division and elongation. In the ctr1-1 mutant background, auxin response is induced at the root tip and an increase in expression of the auxin transporter PIN2 is observed. The authors also found a decrease in the expression of the major stem cell maintenance genes PLETHORA1, SHORT ROOT, and SCARECROW. The defective root phenotype of ctr1-1 is restored in ctr1-1 ein2-1 double mutant, suggesting the importance of CTR1 and EIN2 for maintaining two major pathways, AUX-PIN-PLT and SCR-SHR, for proper root development. (Summary by Arif Ashraf) Plant Science: 10.1016/j.plantsci.2018.11.019