Genome-Wide Identification and Expression Analysis of the GRF and GIF Gene Families in Cassava

Growth regulatory factors (GRFs) and growth-regulating interacting factors (GIFs) play significant roles in plant growth, development, and environmental stress responses. Previous studies have reported the functions of GRF and GIF genes in model plants such as Arabidopsis and rice. Nevertheless, the GRF and GIF genes remained unexplored in cassava. Cassava (Manihot esculenta Crantz) is an important tropical economic crop. Its starchy storage roots serve as a major source of food and industrial raw materials, while its protein-rich leaves are widely consumed as leafy vegetables in Africa and other regions, offering high nutritional value and significant horticultural potential. This study identified 28 MeGRFs distributed on 13 chromosomes and 5 MeGIFs on 4 chromosomes through bioinformatic analysis and expression profiling. Promoter analysis uncovered cis-acting elements associated with growth, hormone signaling, and biotic stress responses. The MeGRFs and MeGIFs genes exhibited differential expression patterns in 11 different tissues. Real-time quantitative PCR analysis showed a significant expression for 11 MeGRFs and 3 MeGIFs under the Xanthomonas phaseoli pv. manihotis (Xpm) treatment. The protein-protein interaction network highlighted a potential GRF-GIF complex with MeGRF28 and MeGIF4 key hub genes. This study provides a theoretical basis for understanding the functional evolution of the GRF and GIF gene families in cassava and their roles in horticultural trait development and stress resistance mechanisms.