I want to share one of the most touching moments in my life.
One day I was cuddling with my S.O. We had our legs entwined. It was the thing he said next which still has me reeling inside:
"We’re like two trees sharing a rhizome."
I spent all weekend reading mostly reviews of seminal work in the plant’s two-tiered immune response to bacterial and fungal pathogens. Unlike us, plants are basically born with their immune system and do not generate “memory” cells that we make when we get sick with, say, chicken pox. Okay, I don’t really remember much about the human immune system, so I apologize for the vagueness. The point is, plants and their co-adapted pathogens are in somewhat of a molecular arms race when it comes to survival.
A plant’s first line of defense is triggered when the plant senses common foreign materials. What are common foreign materials? This is not a legitimate term used by plant pathologists, but it is my common person’s term for Pathogen Associated Molecular Patterns, commonly abbreviated as PAMPs, and one of many unfortunate acronyms that are created to confuse the crap out of the reader and make typing and writing easier for the plant pathologist.
PAMPs, or common foreign materials as I like to think of them, are things that are foreign to plants that are found in many plant invaders. Flagellin, a protein which makes up bacterial flagella, is probably the most well-characterized of these molecules. When a plant recognizes one of these molecules, it elicits a basal immunity response that prevents the pathogen from getting any sort of stronghold in the plant. The plant immediately mounts a reaction and tries to get rid of whatever is bothering it.
So if the plant kills off the bacteria because it has flagellin in it, how does the bacteria persist? This is where evolution gets important. Bacteria disable the first line of defense by secreting a number of evil goodies that help them overcome a plant’s basal immune response. These evil goodies are called effectors. They help the pathogen get established in the plant, generating what a pathologist calls Effector Triggered Susceptibility. So then how does a plant survive this garbage? The plant has to evolve too! So plants have now developed a nice suite of genes called R (resistance) genes which recognize the things that effectors screw around with. This second defense is called Effector Triggered Immunity, and typically results in the “hallmark of ETI” which is the hypersensitivity reaction, AKA localized cell death.
So yeah. That’s plant disease response in a tiny nutshell. There’s a lot more involved but frankly my brain hurts after reading that many reviews over the weekend. I am hoping to write a paper about the evolution of R gene classes in different plant families, but I honestly don’t know if I can get myself to plod through the material when I have so much wet bench work to do.
This has nothing to do with plants, but I recently went on my first ever fossil-hunting trip and came back with some brachiopod imprints and fossilized brachiopods that we picked up in East Stroudsburg, PA from a pile of shale behind a Dairy Queen which is loaded with Devonian marine creatures. Yes, we went fossil hunting behind DQ. I got an Orange Julius halfway through, too. I really enjoyed myself so I think I’ll be posting about a few more fossil hunts when I get the chance to go on them.
The bottom one is my first ever fossil! It’s so cute I can barely stand it, but if I find a trilobite I’ll be dying.
Over drinks and food the other night, my partner and I came up with some analogies for concepts in population genetics that are a little confusing on their own. Check out the real definitions yourself if you’re interested…
When you break up with a great girlfriend and you start aging and getting crabby, making it harder to get another comparable one in the future.
When a bar stays open because they have cheap drinks even though the bathroom smells like 100 years of urine buildup.
When you meet two nice guys but they can’t both be your boyfriend.
When everyone in a work group is so-so or below average but their boss is a genius, so they still persist in their field.
When there’s a small group of friends swimming together in a remote location and the only one of them that knows CPR gets tired first and dies.
When your reputation is ruined in grade school because you have a delinquent older sibling.
When one girl in a group of friends buys Uggs for the first time, and then the rest of the girls get Uggs and start wearing them all year.