Advances in the use of morphogenic regulators and peptide regenerating factors for boosting plant transformation and...

Plant regeneration and transformation remain significant bottlenecks towards the genetic improvement of most crop species by either genome editing or transgenic approaches. Recent research has therefore, transitioned from manual optimization of culture media and components to the use of morphogenic regulators (MRs) and novel peptide regeneration factors that can reprogram somatic cell fate to a totipotent state. For instance, the co-expression of TRs such as GROWTH-REGULATING FACTORs (GRF), and GRF-INTERACTING FACTOR (GIF) have been shown to facilitate regeneration of transgenic plants from recalcitrant varieties. Genotype dependence and low regenerabilty have also constrained the adoption of precision breeding tools such as Cas9, Cas12a, Cas13, base and prime editors for trait improvement in some species and genotypes. This review first explores the status of plant transformation and gene editing techniques, then discusses the mechanisms of key TRs, including those from the WOX, DOF, AP2/ERF, LRR-RLK and KNOX families, and emerging peptide factors like REF1. The review further outlines strategies to deploy these factors via constitutive, tissue-specific, transient, or inducible expression, and highlights how they expedite the production of transgenic and edited events. We have also reviewed applications across monocots (maize, rice, wheat, sorghum), dicots (soybean, rapeseed, tomato, sugar beet), and recalcitrant species (cassava, cacao, tree crops, medicinal plants). We further discuss challenges such as abnormal phenotypes and regulatory hurdles, and survey recent innovations, including inducible CRISPR activation of endogenous genes and new regeneration peptides that pave the way toward more efficient, genotype-flexible plant transformation and gene editing. Overall, this review seeks to highlight recent advancements and future perspectives in the application of TRs and peptide regenerating factors to overcome limitations in advanced biotechnological approaches, hence enhance plant resilience and productivity.