Cytokinin-Dependent Control of GH3 Group II Family Genes in the Arabidopsis Root

Abstract

The Arabidopsis root is a dynamic system where the interaction between different plant hormones controls root meristem activity and, thus, organ growth. In the root, a characteristic graded distribution of the hormone auxin provides positional information, coordinating the proliferating and differentiating cell status. The hormone cytokinin shapes this gradient by positioning an auxin minimum in the last meristematic cells. This auxin minimum triggers a cell developmental switch necessary to start the differentiation program, thus, regulating the root meristem size. To position the auxin minimum, cytokinin promotes the expression of the IAA-amido synthase group II gene GH3.17, which conjugates auxin with amino acids, in the most external layer of the root, the lateral root cap tissue. Since additional GH3 genes are expressed in the root, we questioned whether cytokinin to position the auxin minimum also operates via different GH3 genes. Here, we show that cytokinin regulates meristem size by activating the expression of GH3.5 and GH3.6 genes, in addition to GH3.17. Thus, cytokinin activity provides a robust control of auxin activity in the entire organ necessary to regulate root growth.

A PHABULOSA-Controlled Genetic Pathway Regulates Ground Tissue Patterning in the Arabidopsis Root

“…Plasmids were transformed into Q0990 plants by floral dipping. 44 For EN7>>MIM165/6 transgenic plant, UAS::MIM165/6 transcriptional fusion was obtained as follow: the sequence of MIM165/ 166 was amplified from vector generated by Todesco et al 48 using specific primers (MIM165FW 5 0 -GGGGACAAGTTTGTA CAAAAAAGCAGGCTGGGG CCGCAAAACACCACAAAAACA-3 0 , MIM165REV 5 0 -GGGGACCACTTTGTACAAGAAAGC TGGGTGA ACTAGTGGATCCCCCATCACCAC-3 0 ) and cloned in pDONR221 Gateway vector by BP recombination (Invitrogen). Subsequently pDONRP4P1-UAS, pDONR221-MIM165/6 and pDONR P2P3-NOS were recombined into a pB7m34GW destination vector via LR reaction (Invitrogen).…”

Transcriptomes Analysis Reveals Novel Insight Into the Molecular Mechanisms of Somatic Embryogenesis in Hevea Brasiliensis

“…SAUR genes were consisted of a large multigene family, played crucial roles in regulating plant growth and development [75,76]. GH3 family participated in a series of hormone-dependent processes in plant, including root growth, owering [77,78]. In our study, Auxin signal transduction related genes, IAA9-like, IAA28-like and GH3.1 were high accumulation in CE.…”

Transcriptomes analysis reveals novel insight into the molecular mechanisms of somatic embryogenesis in Hevea brasiliensis

“…SAUR genes were consisted of a large multigene family, played crucial roles in regulating plant growth and development [84,85]. GH3 family participated in a series of hormone-dependent processes in plant, including root growth, and owering [86,87]. In this study, high concentration of IAA and 2,4-D were added in MS medium for inducing EC from immature male owers.…”