Genome-Wide Identification and Structural Characterization of Growth-Regulating Factors (GRFs) in and .

Growth-regulating factors (GRFs) encode plant-specific transcription factors that play a vital role in regulation of plant growth, development, and stress response. Although GRFs have been identified in various plants, there is no reported work available in (commonly known as kiwifruit) so far. In the present study, we identified 22 genes on (hereafter is referred to as Ac, and GRF genes in are referred to as ) distributed on 17 chromosomes and one contig, and 26 genes in (hereafter is referred to as Ae, and GRF genes in are referred to as ) distributed on 21 chromosomes. Phylogenetic analysis showed that kiwifruit GRF proteins were clustered into five distinct groups. Additionally, kiwifruit showed motif composition and gene structure similarities within the same group. Synteny analysis showed that whole-genome duplication played a key role in the expansion of the GRF family in kiwifruit. The higher expression levels of kiwifruit in young tissues and under stress conditions indicated their regulatory role in kiwifruit growth and development. We observed two genes in Ae (, ) and two genes in Ac (, ) significantly upregulated in different RNA-seq datasets. The presence of conserved protein structures and cis-regulatory elements caused functional divergence in duplicated gene pairs. The subcellular localization indicated the presence of kiwifruit in the nucleus of the plant cell. Protein-protein interaction analysis predicted GIF protein orthologs for GRFs and GRFs. Taken together, we systematically analyzed the characterization of kiwifruit GRF family members for their potential role in kiwifruit development and pv. () invasion response. Further functional studies of kiwifruit GRFs in plant growth, development, and stress response will provide valuable insights for kiwifruit breeders.