The soybean Rhg1 amino acid transporter gene alters glutamate homeostasis and jasmonic acid‐induced resistance to soybean cyst nematode

Summary Rhg1 (resistance to Heterodera glycines 1) is an important locus that contributes to resistance against soybean cyst nematode (SCN; Heterodera glycines Ichinohe), which is the most economically damaging disease of soybean worldwide. Simultaneous overexpression of three genes encoding a predicted amino acid transporter, an α‐soluble N‐ethylmaleimide‐sensitive factor attachment protein (α‐SNAP) and a predicted wound‐induced protein resulted in resistance to SCN provided by this locus. However, the roles of two of these genes (excluding α‐SNAP) remain unknown. Here, we report the functional characterization of Glyma.18G022400, a gene at the Rhg1 locus that encodes the predicted amino acid transporter Rhg1‐GmAAT. Although the direct role of Rhg1‐GmAAT in glutamate transport was not demonstrated, multiple lines of evidence showed that Rhg1‐GmAAT impacts glutamic acid tolerance and glutamate transportation in soybean. Transcriptomic and metabolite profiling indicated that overexpression of Rhg1‐GmAAT activated the jasmonic acid (JA) pathway. Treatment with a JA biosynthesis inhibitor reduced the resistance provided by the Rhg1‐containing PI88788 to SCN, which suggested that the JA pathway might play a role in Rhg1‐mediated resistance to SCN. Our results could be helpful for the clarification of the mechanism of resistance to SCN provided by Rhg1 in soybean.