Roles of the 14-3-3 gene family in cotton flowering

Abstract

Background In plants, 14-3-3 proteins, also called GENERAL REGULATORY FACTORs (GRFs), encoded by a large multigene family, are involved in protein–protein interactions and play crucial roles in various physiological processes. No genome-wide analysis of the GRF gene family has been performed in cotton, and their functions in flowering are largely unknown. Results In this study, 17, 17, 31, and 17 GRF genes were identified in Gossypium herbaceum, G. arboreum, G. hirsutum, and G. raimondii, respectively, by genome-wide analyses and were designated as GheGRFs, GaGRFs, GhGRFs, and GrGRFs, respectively. A phylogenetic analysis revealed that these proteins were divided into ε and non-ε groups. Gene structural, motif composition, synteny, and duplicated gene analyses of the identified GRF genes provided insights into the evolution of this family in cotton. GhGRF genes exhibited diverse expression patterns in different tissues. Yeast two-hybrid and bimolecular fluorescence complementation assays showed that the GhGRFs interacted with the cotton FLOWERING LOCUS T homologue GhFT in the cytoplasm and nucleus, while they interacted with the basic leucine zipper transcription factor GhFD only in the nucleus. Virus-induced gene silencing in G. hirsutum and transgenic studies in Arabidopsis demonstrated that GhGRF3/6/9/15 repressed flowering and that GhGRF14 promoted flowering. Conclusions Here, 82 GRF genes were identified in cotton, and their gene and protein features, classification, evolution, and expression patterns were comprehensively and systematically investigated. The GhGRF3/6/9/15 interacted with GhFT and GhFD to form florigen activation complexs that inhibited flowering. However, GhGRF14 interacted with GhFT and GhFD to form florigen activation complex that promoted flowering. The results provide a foundation for further studies on the regulatory mechanisms of flowering.

Family-Wide Evaluation of Multiple C2 Domain and Transmembrane Region Protein in Gossypium hirsutum

“…Gh AGAMOUS-LIKE 8-1/-2 ( GhAGL8-1/-2 ), the homologs of APETALA1 ( AP1 ) in cotton, regulate plant height and early maturity of cotton ( Su et al, 2018 ). GENERAL REGULATORY FACTORs (GRFs) play important roles in flowering regulation and meristem development ( Sang et al, 2021 ). We found that the expressions of GhAGL8-1/2 and GhGRF6 were downregulated in both TRV2:GhMCTP7/12/17 and TRV2:GhKNAT1/2 , suggesting the delayed determination of floral meristem identity ( Figures 9A , B ).…”

The Current Progresses in the Genes and Networks Regulating Cotton Plant Architecture

“…The FAC model reveals the functional conservation of florigen complex, because the three proteins constituting FAC are very conserved in seed plants ( Karlgren et al, 2011 ; Taoka et al, 2011 ). Through genome-wide identification and analysis, we found that there were five FD s and 31 14-3-3 homoeologous gene pairs in G. hirsutum ( Liu et al, 2021 ; Sang et al, 2021 ). GhFT–Gh14-3-3–GhFD1/2 complexes can activate the expression of GhAP1 ,the homologous flower identity gene in cotton, thus promoting the flowering.…”

“…In contrast, GhFT–Gh14-3-3–GhFD3/4/5 complexes in roots activate the expression of AUXIN RESPONSE FACTOR 19 , thereby promoting lateral root development ( Liu et al, 2021 ). The function of FAC in cotton is also influenced by its component 14-3-3 protein, which can either promote or inhibit flowering by regulating the expression of GhAP1 and GhSOC1 ( Sang et al, 2021 ). These studies show that although there is only one FT/SFT protein in polyploid upland cotton, it possesses diverse FD and 14-3-3 proteins available allowing the formation of diversified FACs to regulate different development processes.…”

CRISPR/Cas: The New Frontier in Plant Improvement

“…However, CRISPR/Cas can be a way to overcome this challenge. Recently, Gh14-3-3d genes (involved in stress response) were selected as a target for the improvement in biotic stress response, and this gene was disrupted by CRISPR knockout strategy. Results showed that edited plants presented tolerance to Verticillium dahliae …”