Transcriptome Analysis of Molecular Mechanisms Underlying Phenotypic Variation in Phaseolus vulgaris Mutant ‘nts’

The phenotype of a common bean plant is often closely related to its yield, and the yield of plants with reduced height or poor stem development during growth is low. Mutants serve as an essential gene resource for common bean breeding genetic research. Although model plants and crops are studied to comprehend the molecular mechanisms and genetic basis of plant phenotypes, the molecular mechanism of phenotypic variation in common beans remains underexplored. We here used the mutant ‘nts’ as material for transcriptome sequencing analysis. This mutant was obtained through ⁶⁰Co-γ irradiation from the common bean variety ‘A18’. Differentially expressed genes were mainly enriched in GO functional entries such as cell wall organization, auxin response and transcription factor activity. Metabolic pathways significantly enriched in KEGG analysis included plant hormone signal transduction pathways, phenylpropanoid biosynthesis pathways, and fructose and mannose metabolic pathways. AUX1 (Phvul.001G241500), the gene responsible for auxin transport, may be the key gene for auxin content inhibition. In the plant hormone signal transduction pathway, AUX1 expression was downregulated and auxin transport across the membrane was blocked, resulting in stunted growth of the mutant ‘nts’. The results provide important clues for revealing the molecular mechanism of ‘nts’ phenotype regulation in bean mutants and offer basic materials for breeding beneficial phenotypes of bean varieties.