Salicylic acid and the unique TGA transcription factor controls plant immunity against Pseudomonas syringae in Marchantia polymorpha.
Michavila S, Espinosa-Cores L, Kneeshaw S, Torres S, Siroka J
Plant Signaling
PubMedEvery tomato, rose, and oak tree in your garden relies on a salicylic acid immune system to fight off bacterial diseases, and this research reveals that system is so ancient and essential it has been conserved since before plants even had leaves.
Researchers studied a tiny, flat plant called liverwort — one of the most ancient land plants alive today — to understand how plants defend themselves from harmful bacteria. They found that a natural chemical called salicylic acid (yes, related to aspirin!) acts like an alarm signal that switches on the plant's immune system, and this has been working the same way for half a billion years. By disabling this chemical in liverwort, plants became much more vulnerable to bacterial attack, proving how fundamental this defense system really is.
Key Findings
Salicylic acid-deficient liverwort plants showed significantly compromised immune responses against Pseudomonas syringae bacteria, confirming SA's essential role in bryophyte immunity.
A single TGA transcription factor (MpTGA) controls resistance against Pseudomonas in liverwort, suggesting the SA immune pathway was present and functional over 500 million years ago in early land plants.
The SA/MpTGA immune module activates a cluster of defense genes including secretory peroxidases (MpPR9 subfamily) as an early response to bacterial infection.
chevron_right Technical Summary
Scientists discovered that salicylic acid — the same chemical compound related to aspirin — has been helping plants fight bacterial infections for at least 500 million years, even before flowers existed. By studying a primitive liverwort plant, they confirmed this ancient immune system is controlled by a single gene switch that activates defenses against harmful bacteria.
Abstract Preview
Land plants have co-evolved with microorganisms since their transition to a terrestrial habitat, around 500 million years ago. In angiosperms, salicylic acid (SA) activates plant immunity against h...
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Liverworts are a group of non-vascular land plants forming the division Marchantiophyta. They may also be referred to as hepatics. Like mosses and hornworts, they have a gametophyte-dominant life cycle, in which cells of the plant carry only a single set of genetic information. The division name ...