How jasmonate controls cell activity in roots
The way plants develop and get their shape is in part due to the accumulation of growth hormones (auxins) in susceptible cells. Auxin accumulation is mainly controlled by a complex pattern of intracellular auxin transport during lateral root development. The JASMONATESTEMCELL (Studies on jasmonate modulation of distal stem cell activity in Arabidopsis root) project was established to identify the regulatory mechanism that facilitates transcriptional auxin sensitivity of the PIN-formed (PIN) auxin transporter PIN3. Jasmonates are lipid-based plant hormones that are used to regulate a number of processes, including growth. Researchers applied genetics tools, cell biology and biochemical techniques to the model organism Arabidopsis to study the mechanisms behind jasmonate-regulated distal stem cell maintenance. Project partners found that direct binding to the PIN3 promoter by auxin response transcription factor 7 (ARF7) and the ARF7-regulated FOUR LIPS/MYB124 (FLP) gives PIN3 a temporal 'memory' of auxin stimuli. Researchers also showed that the regulation of auxin sensitivity PIN3 expression as defined by both FLP and ARF is a crucial parameter for lateral root development. Therefore, cooperative action between auxin signalling and other transcription factors could constitute a general mechanism by which the transcriptional auxin sensitivity of genes can be differentially modulated between tissues. JASMONATESTEMCELL outcomes will enable scientists to achieve a greater understanding of how plants retain growth plasticity and how they translate stress cues into growth responses.
