bryophytes
Bryophytes are a group of non-vascular land plants encompassing mosses, liverworts, and hornworts, representing some of the earliest lineages of plants to colonize terrestrial environments. Their study is fundamental to plant science because they illuminate the evolutionary transition from aquatic to land-based life, lacking the vascular tissue and complex reproductive structures of more derived plants. As sensitive indicators of environmental conditions and key contributors to ecosystem moisture retention and nutrient cycling, bryophytes offer insights into both plant evolution and ecological dynamics.
open_in_new WikipediaPubMed · 2026-04-14
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.
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.
