Integration of the metabolome and transcriptome reveals the resistance mechanism to low nitrogen in wild soybean seedling roots

Abstract

Wild soybean is the progenitor of cultivated soybean that has excellent low-nitrogen (N) tolerance. This study revealed the mechanism of resistance to low N in wild soybean seedling roots by analyzing the differences in the physiology, metabolome and transcriptome. Under low-N stress, low-N-tolerant wild soybean seedling roots underwent less growth inhibition, producing longer roots that had a higher carbon (C)/N ratio and C, NO3−, Fe2+, Zn2+, Ca2+, K+ and B3+ contents compared with common wild soybean. The comparison of the metabolomes and transcriptomes of two genotypes of wild soybean revealed that low-N-tolerant wild soybean reduced its energy consumption by decreasing the synthesis of energy-consuming amino acids. In addition, it enhanced the synthesis of proline and secondary metabolites to resist low-N stress. Enhancing the metabolism of shikimic acid was a unique mechanism involved in low-N tolerance of the low-N-tolerant wild soybean. Moreover, some genes involved in flavonoid synthesis were identified. This study could provide a basis for the investigation and application of wild resources in soybean breeding.