Chitooligosaccharides and Arbuscular Mycorrhizal Fungi Enhance Soybean Remediation of Cadmium-Contaminated Soil by Regulating Jasmonic Acid Metabolism and Rhizosphere Fungal Diversity

Abstract

Cadmium (Cd) pollution is a serious environmental problem, and soybean is an essential oil crop worldwide. Cd can enter the biosphere, then represents a grave threat to human health. Therefore, it is imperative to study how to enhance the adaptability of soybeans to Cd stress and manage Cd-contaminated soil. This study found that chitooligosaccharides (CHO) and Arbuscular mycorrhiza fungi (AMF) can affect phenylpropane biosynthesis, flavonoid biosynthesis, phenylalanine metabolism, and Betalain biosynthesis, enhancing soybean antioxidant capacity, protecting the integrity of soybean leaf ultra microstructure, thereby enhancing soybean resistance to Cd stress. CHO and AMF also promote the conversion of Jasmonic acid (JA) to derivatives, relieve the inhibitory effect on soybean growth, and promote soybean growth under Cd stress. CHO and AMF abate the concentration of Cd in contaminated soil through growth dilution effect, and the abundance of Cd-tolerant fungi in rhizosphere soil increased, such as Trichoderma, Trichosporon, and Cladosporium, which has a positive significance in reducing the Cd content in contaminated soil. This research can shed new light on the remediation of Cd pollution and the rehabilitation of Cd-contaminated land through the utilization of marine polysaccharides and arbuscular mycorrhizal fungi.

Keywords: Cadmium stress, Phytoremediation, Chitooligosaccharides, Arbuscular mycorrhiza fungi, Jasmonic acid