Alberto Macho

A bacterial type III effector hijacks plant ubiquitin proteases to evade degradation Author summary Most bacterial plant pathogens inject effector proteins inside host cells to suppress immune responses and manipulate other plant functions in order to cause disease. Even though these ...

Together with our previous report earlier this year (Yu et al, PLoS Pathogens, 2025), this work suggests that hijacking plant kinases is an important strategy for bacterial effectors to promote their own phosphorylation and stability in plant cells

doi.org/10.1371/jour...

These phosphorylation sites seem to be important for RipBM contribution to virulence in tomato, reflecting an effector strategy to promote its own stability and contribute to bacterial virulence

However, RipBM is phosphorylated by SnRK-family proteins in plant cells and subsequently associates with plant 14-3-3 proteins, which prevent RipBM ubiquitination and degradation

RipBM is an unconventional type-III effector from Ralstonia, in the sense that it encodes a kinase domain, although, in our experience, kinase activity is not detectable. Sustained RipBM expression in eukaryotic cells leads to cell death, which seems to be a toxic effect of RipBM activity

Phosphorylation‐dependent association of a bacterial effector with plant 14‐3‐3 proteins enhances effector stability and bacterial virulence Gram-negative bacterial pathogens inject effector proteins inside plant cells using specialized secretion systems. These effectors manipulate plant cellular functions and suppress the plant immune s...

Our latest paper is now online at New Phytologist!
 
Phosphorylation-dependent association of a bacterial effector with plant 14-3-3 proteins enhances effector stability and bacterial virulence
 
doi.org/10.1111/nph....

@newphyt.bsky.social

The Ralstonia solanacearum effector RipAV targets plant U‐box proteins and induces proteasomal‐dependent degradation of BIK1 Plants have developed a complex immune system to detect and respond to invading pathogens. A critical aspect of this defense relies on regulatory mechanisms that control the activation of immune res...

Our new paper is out in New Phytologist! We describe how the Ralstonia solanacearum effector RipAV suppresses plant immunity by directly interfering with key defense regulators. 🧵👇
nph.onlinelibrary.wiley.com/doi/10.1111/...

My guess is it forms an “imperfect” complex that mediates a different type of recognition of flg22Rso and a subsequent activation that does engage all the usual downstream targets, but only some of them

This reminds me the treatments with the flg22G/A mutant peptide we did in Sun et al, Science, 2013 (doi.org/10.1126/scie...). That mutation abolishes BAK1 interaction and activation, significantly reduces ROS, but does not affect MAPK activation

Hopefully, the information that heterologous PRR expression can confer novel PAMP recognition could provide new information for the design of synthetic immune receptors with expanded recognition of polymorphic pathogen elicitors

Long story short, it seems that AtFLS2, when expressed in N. benthamiana, associates with NbSERKs and mediate a “partial” complex activation that leads to some downstream responses (MAPK, gene expression), but not others (ROS). Eventually, this enhances disease resistance

We did not see any gain of flg22Rso-triggered ROS burst, but…

there was MAPK activation. Surprisingly, what was supposed to be a “negative control”, even WT AtFLS2 expressed in N. benthamiana would confer MAPK activation upon flg22Rso treatment

An immune receptor complex evolved in soybean to perceive a polymorphic bacterial flagellin - Nature Communications Ralstonia solanacearum evades plant immunity by producing an atypical flagellin protein, thus causing bacterial wilt disease. Here, Wei et al. show that soybean has evolved a divergent flagellin recep...

Before, we identified 2 residues in soybean FLS2 that contribute to the gain of recognition of the polymorphic Ralstonia flg22 (see attached paper)
doi.org/10.1038/s414...

Then we tried to see if mutating the equivalent residues in Arabidopsis FLS2 would confer recognition

Our latest article is now online!
@PlantBiotechnologyJournal

Expression of Arabidopsis FLS2 in N. benthamiana confers responsiveness to Ralstonia flg22 and activation of anti-bacterial immunity
doi.org/10.1111/pbi....

By Meng Li, Yujiao Chen, and Yali Wei

A woman giving a scientific talk with a PowerPoint slide showing a colorful micrograph and test indicating that spatial structure is the basis for division of labor

Absolutely gorgeous images showing expression reporters in Pseudomonas syringae from @type3lab.bsky.social - variety in flagella and type iii secretion system expression within a group of cells.
#2025ISMPMI

Please don't miss it! A great session on the spatial and temporal regulation of plant–microbe interactions, hosted by @uprogress.bsky.social and @tatsuyanobori.bsky.social Many attractive talks, including our latest research presented by @crbeuzon.bsky.social

#ISMPMI2025 #MicroSky #PlantScience

Proteome profiling of plant Cajal bodies uncovers kingdom-specific components Insight into the molecular composition of cellular microenvironments is essential for understanding their function. Membraneless organelles (MLO), such as the nuclear Cajal body (CB), play fundamental...

Cajal bodies are membraneless structures with fundamental roles across eukaryotes—but which proteins actually make them up? Using FAPS, Zhou et al. isolated 34 million plant Cajal bodies and profiled their proteome via LC-MS/MS. Curious? Check out our latest preprint! www.biorxiv.org/content/10.1...

Infographic on the chemistry of a mojito. Some key chemical components of rum, mint, lime and brown sugar are detailed with chemical structures.

It's Friday and it's #NationalMojitoDay!

Here's some of the chemistry behind this refreshing minty cocktail 🍹 www.compoundchem.com/2020/07/10/m...

#ChemSky 🧪

It was such a pleasure to host @albertopmacho.bsky.social at the @zmbp-tuebingen.bsky.social —in his little detour on his way to Cologne for the #2025ISMPMI. “Deciphering the interaction between plants and bacterial pathogens: beyond activation and suppression of immunity”—what a treat we got!

Happy and proud to participate in this collaboration between my home countries 🇪🇸🇨🇳

Pseudomonas syringae subpopulations cooperate by coordinating flagellar and type III secretion spatiotemporal dynamics to facilitate plant infection Nature Microbiology - Single-cell gene expression analysis reveals phenotypic heterogeneity to enable bacterial specialization over the course of plant colonization.

How Bacteria Outsmart Plants—Then Flee the Scene!

#MicroSky #PlantScience #Pseudomonas

Our new research in Nature Microbiology uncovers the sophisticated teamwork of Pseudomonas syringae, a notorious plant pathogen.

🔗 rdcu.be/egczU