GWAS identifies two novel loci for photosynthetic traits related to phosphorus efficiency in soybean

Phosphorus (P) is essential for the growth and development of plants, playing crucial roles in energy acquisition, storage and utilization, regulation of enzyme activities, and yield formation. Therefore, P deficiency in soil is a main factor restricting crop production. The main reason is that crop yields depend on photosynthesis which is vulnerable to low P stress. Thus, it is important to study the relationship between photosynthesis and P efficiency. In this study, we evaluated the P efficiency by using the photosynthesis-related traits in 219 diverse soybean accessions across three different environments and dissected the underlying mechanism using a high-resolution genome-wide association study (GWAS). In total, 30 significant SNPs distributed in 14 genomic regions were identified to be associated with three photosynthesis-related traits under different P levels. Among the 14 associated regions, two regions ( qP13 and qP19 ) were both found in two environments and explained 14.01% and 16.75% of the phenotypic variation, respectively. Furthermore, seven candidate genes underlying qP13 and qP19 were considered promising candidates involved in both soybean photosynthetic and low P tolerance. In all, we uncover two novel environmentally stable major genomic regions of P efficiency by using photosynthesis-related traits, which may provide more information for marker-assisted breeding in soybean and laying the foundation for simultaneously improving P efficiency and photosynthetic capacity.