A phosphorylation module regulates soybean basal immunity

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Zhang et al. identify a signaling cascade mediating soybean cyst nematode resistance.

 https://doi.org/10.1093/plcell/koae008

 By Lei Zhang and Xiaoli Guo, National Key Laboratory of Agricultural Microbiology, College of Plant Science and Technology, Huazhong Agricultural University

Background: The soybean cyst nematode (Heterodera glycines Ichinohe) is considered the most economically important soybean (Glycine max) pathogen. It is widely distributed in soybean-producing regions and is responsible for substantial annual yield losses. These nematodes invade the soybean root system, migrate intracellularly, and cause extensive damage to host tissues. The signaling components orchestrating the activation of plant defense responses during the early stages of nematode infection, particularly in roots, remain largely unknown.

Question: What role does phosphorylation-dependent signaling play in soybean resistance against the soybean cyst nematode?

Findings: Here, we identified a signaling module conferring resistance to soybean cyst nematodes. We demonstrated that GmCDL1, a relatively understudied receptor-like cytoplasmic kinase highly expressed in soybean roots, directly links L-type lectin receptor kinases (LecRKs) to mitogen-activated protein kinase (MAPK) activation during cyst nematode resistance. Additionally, we highlighted an important role of MAPK-mediated phosphorylation in regulating GmCDL1 stability, indicating a positive feedback mechanism to boost immune responses. Our data provide mechanistic insights into the early signaling pathways regulating soybean basal immune responses.

Next steps: Phosphorylation of GmCDL1 attenuates its proteasome-mediated degradation; further investigation into the underlying mechanism is warranted. In addition, identifying elicitors for the LecRK receptors presents a challenging yet exciting area for exploration.

Reference:

Lei Zhang, Qun Zhu, Yuanhua Tan, Miaomiao Deng, Lei Zhang, Yangrong Cao, Xiaoli Guo. (2024). Mitogen-activated protein kinases MPK3 and MPK6 phosphorylate receptor-like cytoplasmic kinase CDL1 to regulate soybean basal immunity https://doi.org/10.1093/plcell/koae008