"Functional Dynamics of Peptide-Receptor Signaling in Plant Immunity." by Dr. Libo Shan / "Resistance, Resilience, and Reconciliation: Lessons from Plant Genetics" by Dr. Ping He

演題

"Functional Dynamics of Peptide-Receptor Signaling in Plant Immunity." by Dr. Libo Shan / "Resistance, Resilience, and Reconciliation: Lessons from Plant Genetics" by Dr. Ping He

講演者

Dr. Libo Shan (Department of Molecular, Cellular, and Developmental Biology, University of Michigan /
Dr. Ping He (Department of Molecular, Cellular, and Developmental Biology, University of Michigan)

使用言語

English

日時

2026年2月17日(火曜日) 14：00～16：00

場所

Biological Science Seminar Hall(L11)

内容

Dr. Libo Shan：
Plants, like animals, rely on complex immune systems to survive constant exposure to microbes in their environment. Rather than mobile immune cells, plants use signaling molecules and receptors at the cell surface to detect danger and coordinate defense responses. In this talk, I will focus on small secreted peptides that act as immune signals in plants, often referred to as phytocytokines because of their functional similarity to cytokines in mammals. These peptides help amplify immune responses, communicate stress signals within the plant, and fine-tune defenses during infection. Perception of these signals depends on receptor kinases located at the cell surface, which act as key hubs for sensing both microbial molecules and plant-derived danger cues. Some receptor kinases serve as shared partners for multiple immune receptors, making them central control points in plant immunity. Not surprisingly, pathogens have evolved strategies to interfere with these receptor systems to avoid detection. In response, plants activate alternative signaling pathways and internal immune receptors to restore defense and, when necessary, trigger localized cell death to stop pathogen spread. I will discuss how peptide signaling and receptor kinases work together to regulate plant immune responses, how these processes are controlled by protein modification and calcium signaling, and how ongoing interactions between plants and pathogens reflect a long evolutionary arms race. Together, these studies provide insight into how plants balance sensitivity, robustness, and flexibility in their immune systems.

Dr. Ping He:
The innate immune system is instrumental in shaping organismal health, disease, and autoimmune disorders. Plant immune receptors include cell surface-resident pattern recognition receptors (PRRs) and intracellular nucleotide-binding domain leucine-rich repeat proteins (NLRs), functional analogs of mammalian Toll-like and NOD-like receptors. Coordination between plant PRR and NLR signaling is essential for establishing a robust defense response against infections. However, excessive or misregulated defense could be detrimental to the host, leading to autoimmunity and even death.
To understand how plants achieve effective resistance and resilience without running amok, our laboratory has implemented sensitive and high-throughput genetic screens using the reference plant Arabidopsis. Disruption of key immune regulators, such as BAK1, a shared coreceptor of multiple PRRs, or components of the downstream MAP kinase cascade, results in constitutive defense activation and severe autoimmunity. To identify mechanisms that restrain these responses, we conducted an RNA interference (RNAi)–based genetic screen for suppressors of immunity-associated cell death, uncovering a series of “bak to life” (BTL) and “lethality suppressor of mekk1” (LET) mutants.
This talk will focus on the molecular, biochemical, and cellular mechanisms by which BTLs and LETs modulate immune activation, providing insight into how plants reconcile PRR- and NLR-mediated immunity without tipping into over-defense. Together, these genetic lessons illustrate how immune systems are wired not only to combat pathogens, but also to restore balance and maintain immune homeostasis.

問合せ先

Plant immunity
Yusuke Saijo (saijo@bs.naist.jp)