Overexpression of Gene Delays Leaf Senescence and Improves Grain Yield in Maize

Cytokinins (CTKs) are a major phytohormone group that are significant in the promotion of cellular division, growth, and divergence. () regulates a rate-limiting step in plant CTK synthesis, promotes the synthesis of isopentenyl adenonucleotides from 5-AMP and isopentenyl pyrophosphate, and then converts both these chemicals into various CTKs. Here, the full-length cDNA of , which encodes 322 amino acids, was isolated and was introduced into a maize inbred line by -mediated transformation. In both controlled environments and field experiments, the overexpression of gene in the transformed plants delayed leaf senescence. Compared to the receptor line, the transgenic maize lines retained higher chlorophyll levels, photosynthetic rates, and cytokinin content for an extended period of time, and produced significantly higher grain yield by a margin of 17.71-20.29% under normal field planting conditions. Subsequently, ten possible genes that interacted with were analyzed by qRT-PCR, showing that the expression pattern of was consistent with expression. Through comprehensive analysis, we screened for transgenic lines with stable inheritance of gene, clear functional efficiency, and significant yield improvement, in order to provide theoretical basis and material support for the breeding of new high-yield transgenic maize varieties.