Cutting to the base: Identifying regulators of adventitious rooting.

Adventitious roots are distinct from primary and lateral roots in that adventitious roots develop ectopically from aboveground organs. Whole-genome microarrays in poplar provided the first glimpse into the gene networks that are remodeled in cells prior to the development of adventitious roots. In the first 24 hr after removal of stem cuttings, over one-half of the transcripts encoded in the genome showed evidence of differential abundance in the cells that will eventually give rise to adventitious roots. Major processes that were regulated appear related to physiological adaptation of the cutting to acute loss of water and nutrients as well as hormone signaling. Comparative transcriptome analysis of genotypes that differ in their competence to form adventitious roots may be a generally useful strategy to identify genes that regulate adventitious rooting efficiency.