Identification of genes encoding GRF transcription factors in Taraxacum kok-saghyz Rodin and their potential role in response to salt stress.

GRF transcription factors (GRF) are pivotal regulators of plant development and stress tolerance, but their functional repertoire in the rubber crop Taraxacum kok-saghyz (Russian dandelion) remains entirely uncharacterized. Genome-wide analysis of the T. kok-saghyz genome identified 10 TkGRF members, unevenly distributed across eight chromosomes and phylogenetically resolved into five clades. All TkGRFs contained the canonical QLQ and WRC domains, confirming their identity as bona fide GRF transcription factors. Synteny analysis further established close evolutionary conservation of these 10 TkGRF members with Asteraceae relatives, while promoter profiling revealed pervasive cis-regulatory elements linked to hormonal and stress signaling, pointing to a broad regulatory potential. Integrated RNA-seq and qRT-PCR analyses confirmed the tissue-specific expression profiles of TkGRFs under salt stress. Notably, TkGRF1, a nucleus-localized transcription factor displaying transcriptional activation activity, exhibited the most robust response to stress. Overexpression of TkGRF1 in Arabidopsis resulted in elevated Malondialdehyde (MDA) and reactive oxygen accumulation, while lowering antioxidant enzyme activities, confirming its negative role in salt tolerance. RNA-seq further uncovered salt-triggered transcriptional reprogramming of hormone signaling, energy metabolism and stomatal development pathways. This study lays a theoretical basis and offers a potential target for the molecular breeding of salt-tolerant T. kok-saghyz.