Samuel Eastman
@seastman.bsky.social
🇺🇸 👨🔬
Postdoc @Princeton
🌱🪛🧪🦠➡️🌱🌱🌱
Ph.D. @UNL_PlantPath
🌱💉🦠➡️🦠🦠🦠🦠
Postdoc @Princeton
🌱🪛🧪🦠➡️🌱🌱🌱
Ph.D. @UNL_PlantPath
🌱💉🦠➡️🦠🦠🦠🦠
In short, commensal Xanthomonadales bacteria like Dyella japonica secrete the type II subtilase IssA that cleaves immune elicitors like flg22 and suppresses plant immune activation.
December 16, 2024 at 10:02 PM
In short, commensal Xanthomonadales bacteria like Dyella japonica secrete the type II subtilase IssA that cleaves immune elicitors like flg22 and suppresses plant immune activation.
We found IssA homologs in all of our suppressive Xanthomonadales, and we found it contributed to suppression of flg22-induced immune activation in all of those tested. This suggests secretion of PAMP-degrading subtilases is evolutionarily conserved. Think of them like "chill pills"!
December 16, 2024 at 10:02 PM
We found IssA homologs in all of our suppressive Xanthomonadales, and we found it contributed to suppression of flg22-induced immune activation in all of those tested. This suggests secretion of PAMP-degrading subtilases is evolutionarily conserved. Think of them like "chill pills"!
IssA cleaves flg22 (both the canonical sequence, and the altered sequence from Dyella japonica) as well as the immune elicitor peptide AtPEP1 in vitro, and we observed specific fragments generated from this cleavage.
December 16, 2024 at 10:02 PM
IssA cleaves flg22 (both the canonical sequence, and the altered sequence from Dyella japonica) as well as the immune elicitor peptide AtPEP1 in vitro, and we observed specific fragments generated from this cleavage.
We found a type II secreted effector in Dyella japonica which, spoilers, we named "Immunosuppressive subtilase A", or IssA. IssA is enzymatically active serine protease which contributes Dyella japonica's suppression of flg22-induced immune activation. (In the figure, blue roots=immune activation)
December 16, 2024 at 10:02 PM
We found a type II secreted effector in Dyella japonica which, spoilers, we named "Immunosuppressive subtilase A", or IssA. IssA is enzymatically active serine protease which contributes Dyella japonica's suppression of flg22-induced immune activation. (In the figure, blue roots=immune activation)
We assumed that bacteria that could suppress flg22-induced root growth inhibition would be equally good at suppressing flg22-induced root growth inhibition…but we were wrong! We found some could suppress one more effectively than the other. 🤔
December 16, 2024 at 10:02 PM
We assumed that bacteria that could suppress flg22-induced root growth inhibition would be equally good at suppressing flg22-induced root growth inhibition…but we were wrong! We found some could suppress one more effectively than the other. 🤔
This cluster of bacteria is interesting: they are all really good at blocking flg22-induced root growth inhibition! All of these isolates are from order Xanthomonadales. Do they share a conserved mechanism? More on that in a moment.
December 16, 2024 at 10:02 PM
This cluster of bacteria is interesting: they are all really good at blocking flg22-induced root growth inhibition! All of these isolates are from order Xanthomonadales. Do they share a conserved mechanism? More on that in a moment.
We typically associate suppression of plant immunity with pathogens, but commensal bacteria suppress immunity too! To find out how common this is, we screened 165 root-associated bacteria for suppression immune activation and growth restriction in response to the immune eliciting peptide flg22.
December 16, 2024 at 10:02 PM
We typically associate suppression of plant immunity with pathogens, but commensal bacteria suppress immunity too! To find out how common this is, we screened 165 root-associated bacteria for suppression immune activation and growth restriction in response to the immune eliciting peptide flg22.
You don't have to be a microbiologist to know that dirt is dirty! 🦠 Plant roots are covered in microbes: pathogens, mutualists and commensals. Plants grow in association with this rhizosphere microbiome, but they can't afford to be germophobic: activating the immune system reduces growth!
December 16, 2024 at 10:02 PM
You don't have to be a microbiologist to know that dirt is dirty! 🦠 Plant roots are covered in microbes: pathogens, mutualists and commensals. Plants grow in association with this rhizosphere microbiome, but they can't afford to be germophobic: activating the immune system reduces growth!
One of the big questions in molecular plant pathology is how can plants balance growth and defense. 🌱⚖️🛡️🦠Check out our new research, that shows how some commensal bacteria secrete a protease that cleaves immune-activating peptides and suppress plant immune activation! doi.org/10.1016/j.ce...
December 16, 2024 at 10:02 PM
One of the big questions in molecular plant pathology is how can plants balance growth and defense. 🌱⚖️🛡️🦠Check out our new research, that shows how some commensal bacteria secrete a protease that cleaves immune-activating peptides and suppress plant immune activation! doi.org/10.1016/j.ce...
In short, commensal Xanthomonadales bacteria like Dyella japonica secrete the type II subtilase IssA that cleaves immune elicitors like flg22 and suppresses plant immune activation.
December 16, 2024 at 9:51 PM
In short, commensal Xanthomonadales bacteria like Dyella japonica secrete the type II subtilase IssA that cleaves immune elicitors like flg22 and suppresses plant immune activation.
We found IssA homologs in all of our suppressive Xanthomonadales, and we found it contributed to suppression of flg22-induced immune activation in all of those tested. This suggests secretion of PAMP-degrading subtilases is evolutionarily conserved. Think of them like "chill pills"!
December 16, 2024 at 9:51 PM
We found IssA homologs in all of our suppressive Xanthomonadales, and we found it contributed to suppression of flg22-induced immune activation in all of those tested. This suggests secretion of PAMP-degrading subtilases is evolutionarily conserved. Think of them like "chill pills"!
IssA cleaves flg22 (both the canonical sequence, and the altered sequence from Dyella japonica) as well as the immune elicitor peptide AtPEP1 in vitro, and we observed specific fragments generated from this cleavage.
December 16, 2024 at 9:51 PM
IssA cleaves flg22 (both the canonical sequence, and the altered sequence from Dyella japonica) as well as the immune elicitor peptide AtPEP1 in vitro, and we observed specific fragments generated from this cleavage.
We found a type II secreted effector in Dyella japonica which, spoilers, we named "Immunosuppressive subtilase A", or IssA. IssA is enzymatically active serine protease which contributes Dyella japonica's suppression of flg22-induced immune activation. (In the figure, blue roots=immune activation)
December 16, 2024 at 9:51 PM
We found a type II secreted effector in Dyella japonica which, spoilers, we named "Immunosuppressive subtilase A", or IssA. IssA is enzymatically active serine protease which contributes Dyella japonica's suppression of flg22-induced immune activation. (In the figure, blue roots=immune activation)
We assumed that bacteria that could suppress flg22-induced root growth inhibition would be equally good at suppressing flg22-induced root growth inhibition…but we were wrong! We found some could suppress one more effectively than the other. 🤔
December 16, 2024 at 9:51 PM
We assumed that bacteria that could suppress flg22-induced root growth inhibition would be equally good at suppressing flg22-induced root growth inhibition…but we were wrong! We found some could suppress one more effectively than the other. 🤔
This cluster of bacteria is interesting: they are all really good at blocking flg22-induced root growth inhibition! All of these isolates are from order Xanthomonadales. Do they share a conserved mechanism? More on that in a moment.
December 16, 2024 at 9:51 PM
This cluster of bacteria is interesting: they are all really good at blocking flg22-induced root growth inhibition! All of these isolates are from order Xanthomonadales. Do they share a conserved mechanism? More on that in a moment.
We typically associate suppression of plant immunity with pathogens, but commensal bacteria suppress immunity too! To find out how common this is, we screened 165 root-associated bacteria for suppression immune activation and growth restriction in response to the immune eliciting peptide flg22.
December 16, 2024 at 9:51 PM
We typically associate suppression of plant immunity with pathogens, but commensal bacteria suppress immunity too! To find out how common this is, we screened 165 root-associated bacteria for suppression immune activation and growth restriction in response to the immune eliciting peptide flg22.
You don't have to be a microbiologist to know that dirt is dirty! 🦠 Plant roots are covered in microbes: pathogens, mutualists and commensals. Plants grow in association with this rhizosphere microbiome, but they can't afford to be germophobic: activating the immune system reduces growth!
December 16, 2024 at 9:51 PM
You don't have to be a microbiologist to know that dirt is dirty! 🦠 Plant roots are covered in microbes: pathogens, mutualists and commensals. Plants grow in association with this rhizosphere microbiome, but they can't afford to be germophobic: activating the immune system reduces growth!
Their percentages come from this paper: pmc.ncbi.nlm.nih.gov/articles/PMC... which reports NAD+ changes from their treatment by the change in blood NAD+ in µg/mL, but doesn't report the actual measurements. The paper keeps calling this a % increase but doesn't report the value of the baseline 😱
December 16, 2024 at 11:39 AM
Their percentages come from this paper: pmc.ncbi.nlm.nih.gov/articles/PMC... which reports NAD+ changes from their treatment by the change in blood NAD+ in µg/mL, but doesn't report the actual measurements. The paper keeps calling this a % increase but doesn't report the value of the baseline 😱
Maybe I should make my next graph look like this. Where are the data points?
December 16, 2024 at 11:37 AM
Maybe I should make my next graph look like this. Where are the data points?
Pulled up my dried tomato plants today. Surprised to see anthocyanin accumulation in the roots of my transgenic Norfolk Purple Tomatoes! A great example of engineered gene expression in off-target tissues!
November 29, 2024 at 7:24 PM
Pulled up my dried tomato plants today. Surprised to see anthocyanin accumulation in the roots of my transgenic Norfolk Purple Tomatoes! A great example of engineered gene expression in off-target tissues!