PheGRF4e initiated auxin signaling during moso bamboo shoot development.

Background: As a ubiquitous acid-regulating protein family in eukaryotes, general regulatory factors (GRFs) are active in various life activities of plants. However, detailed investigations of the GRFs gene family in moso bamboo are scarce.

Methods And Results: Genome-wide characteristics of the GRF gene family in moso bamboo were analyzed using the moso bamboo genome. GRF phylogeny, gene structure, conserved domains, cis-element promoters, and gene expression were systematically analyzed. A total of 20 GRF gene family members were identified in the moso bamboo genome. These genes were divided into ε and non-ε groups. qRT-PCR (real-time quantitative reverse transcription polymerase chain reaction) showed that PheGRF genes responded to auxin and gibberellin treatment. To further study PheGRF gene functions, a yeast two-hybrid experiment was performed and verified by a bimolecular fluorescence complementation experiment. The results showed that PheGRF4e could interact with PheIAA30 (auxin/indole-3-acetic acid, an Aux/IAA family gene), and both were found to act mainly on the root tip meristem and vascular bundle cells of developing shoots by in situ hybridization assay.

Conclusions: This study revealed that PheGRF genes were involved in hormone response during moso bamboo shoot development, and the possible regulatory functions of PheGRF genes were enriched by the fact that PheGRF4e initiated auxin signaling by binding to PheIAA30.