Biology subjects

Magomedov, M.

Publications and source records attributed to Magomedov, M..

3 recordsLinked to original sources

bioRxiv2026

Two homologous Alt a1-like fungal proteins possess dual activities in HIR-associated immune signaling and EDS1-dependent cell death

Necrotrophic fungi secrete numerous Cell Death-Inducing Proteins (CDIPs) that manipulate host immunity to promote disease, yet the signaling pathways underlying their phytotoxic activity remain poorly understood. Here, we identify the Botrytis cinerea Hypersensitive response-inducing protein 1 (Hip1) as a close homolog of the recently described Sclerotinia sclerotiorum effector Plant Early Immunosuppressive Effector 1 (PEIE1) and investigate the molecular basis of its activity. HIP1 and PEIE1 share high sequence similarity and a conserved AlphaFold-predicted Alt a1-like fold, they interact with the Arabidopsis plasma membrane protein HIR4, and they induce strong necrosis in Nicotiana benthamiana. Despite their high structural similarity, Hip1 and PEIE1 differ in their reported roles during fungal infection. Unexpectedly, Hip1-induced cell death requires the central immune regulator ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1) as well as the downstream helper NLR network comprising ADR1 and NRG1. Together, our findings establish Hip1 as a closely related homolog of PEIE1 and suggest that these closely related Alt a1-like proteins possess dual activities: modulation of HIR-associated immune signaling and activation of EDS1-dependent host cell death.

plant biology↗

bioRxiv2026

Deletion of 29 cell death-inducing proteins and phytotoxin biosynthetic genes does not completely abolish virulence of Botrytis cinerea

Botrytis cinerea is a necrotrophic plant pathogen with an extremely wide host range. During invasion, the fungus induces rapid host cell death and proliferates in the necrotic tissue. Host killing involves secretion of lytic enzymes, phytotoxic metabolites and cell death inducing proteins (CDIPs), but their relative contributions are poorly understood. We have previously shown that the sequential knockout of up to 12 CDIPs leads to a substantial reduction of virulence of B. cinerea mutants. In this study, we identified additional CDIPs and generated an unprecedented series of multi-gene deletion mutants in a filamentous fungus, culminating in a 29x mutant carrying deletions of 27 CDIP-encoding genes and two genes required for the biosynthesis of the phytotoxins botrydial and botcinic acid. These multi-k.o. mutants were strongly reduced in virulence and almost unable to infect apple fruit tissue, but still induced slowly expanding necrosis on leaves, demonstrating that additional determinants of host killing remain to be identified. Overexpression of the highly phytotoxic Nep1 in a 22-fold CDIP mutant failed to increase its virulence. Reevaluation of several CDIPs previously described as virulence factors revealed for most of them only small or no significant contributions to pathogenesis. Generation of a mutant lacking all six predicted endo-polygalacturonases confirmed only for PG1 and PG2 a major role for cell wall degradation and infection. Our work demonstrates that necrotrophic pathogenesis in B. cinerea does not depend on a few primary virulence determinants, but rather on a highly redundant network of host damaging factors.

molecular biology↗

bioRxiv2025

Gas5A, a putative glucanosyltransferase from Botrytis, functions as cell death inducing protein in plants

The necrotrophic fungus Botrytis cinerea, releases numerous phytotoxic, cell death inducing proteins (CDIPs) during infection. The precise role of these proteins and their molecular function, however, is still unknown. Here, we report on the identification of a previously unknown CDIP, the glucanosyltransferase Gas5A. Functional characterization revealed that the C-terminal 60 aa of Gas5A are sufficient to induce cell death, independent from its putative enzymatic function. Gas5A localization and functional dependence on the receptor-associated kinase suppressor of BIR1-1 (SOBIR1) and the plant defense regulator ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1) indicate recognition as a pathogen-associated molecular pattern (PAMP) at the plant plasma membrane, but it is toxic also when delivered inside plant cells. Generation of a CRISPR/Cas9-assisted Botrytis knockout strain did not indicate any impact of Gas5A on virulence. Taken together, Gas5A represents a novel PAMP-like CDIP with additional intracellular phytotoxic activity.

plant biology↗