Analysis of flowering-associated gene expressions and metabolic characteristics in adzuki bean (Vigna angularis L.) with different short-day induction

Abstract

Abstract Background Adzuki bean is an important miscellaneous grain crop and a kind of typical short-day crop that is used in a variety of foods because of its high nutritional and medicinal value. The flowering time of adzuki beans is affected by multiple environmental factors, particularly the photoperiod. Adzuki bean can meet at flowering period, accelerate breeding process and avoid natural disasters by adjusting the day-length.Therefore, RNA-seq analysis was used to determine the effects of different day-length on the expression and metabolic characteristics of genes related to flowering time in adzuki beans. Results In this study, ‘Tangshan Hongxiaodu’ was used as experimental material. Transcriptome sequencing was performed under SD-5d, SD-10d and SD-15d treatments, respectively. The results showed that a total of 5,939 differentially expressed genes (DEGs) were identified by sequencing, Among these common genes, 38.09% were upregulated and 23.81% were downregulated in three groups. Gene Ontology (GO) enrichment analysis was performed on the target genes to identify common functions related to photosystem I and II. Kyoto Encyclopedia of Genes and Genomes (KEGG) enriched analysis was performed t o predict two pathways involved in antenna proteinand circadian rhythm. And that the flowering of adzuki beans was promoted by downregulating genes in the circadian rhythm pathway through the blue light metabolic pathway, whereas the antenna protein promoted flowering by enhancing the reception of light signals and accelerating electron transport. In these two metabolic pathways, the number of DEGs was the greatest changes in SD-5d vs SD-15d comparison group. Real-time qRT-PCR validation of eight DEGs in these two metabolic pathways was consistent with the transcriptome results, indicating that the sequencing results were accurate and reliable and that these genes may be candidate genes affecting the regulation of short-day induction at the adzuki bean seedling stage. Conclusion The results indicated that short-day induction can downregulate the expression of genes related to adzuki bean flowering in the circadian rhythm and upregulate the expression of some genes in the antenna protein pathway. In addition, the results not only provide a theoretical reference for the molecular mechanism of adzuki bean flowering induced by short days, but also provide multi-level information on the next steps in exploring the functional verification of key genes regulating adzuki bean flowering.