Recently, the latest research results of Professor Kenichi Tsuda’s team at the State Key Laboratory of Agricultural Microbiology of Huazhong Agricultural University and the School of Plant Science and Technology have been published, revealing the cruciferous plants The evolutionary mechanism of the PTI immune response.
During the long-term evolution of plants, the variation of stress-responsive genes is crucial for plants to adapt to environmental changes. However, the evolutionary mechanism of gene transcription in plants under stress is still unclear. Plants have evolved membrane-localized pattern recognition receptors (PRR) to recognize microbial-related molecular patterns (MAMPs) conserved on the surface of pathogenic microorganisms and activate pattern-induced immune responses (PTI). For example, the oligopeptide flg22 at the N-terminus of bacterial flagellin can be recognized by the Arabidopsis receptor FLS2, triggering a series of PTI immune responses including MAPK phosphorylation, transcription reprogramming, and hormone synthesis, thereby increasing plant resistance to pathogens. At present, people’s understanding of the evolutionary mechanism of PTI is only limited to the evolution of PRR, and little is known about the conservation and evolutionary mechanism of PTI immune response among different plants.
researchers used flg22 to treat six Arabidopsis lines and three cruciferous relatives (including shepherd’s purse Capsella rubella, cardamine hirsuta and salt mustard) Eutrema salsugineum), found that all four cruciferous plants can sense flg22 and trigger an early PTI response, but the plant growth inhibition and pathogen resistance caused by the PTI response induced by flg22 are significantly different among the four plants.
Arabidopsis thaliana with different genetic backgrounds and geographical origins The transcriptional response of strains to flg22 is highly consistent
To study the evolution of the PTI immune response at the transcriptional level, the researchers compared and analyzed six Arabidopsis strains and three cruciferous plants treated with flg22 Transcriptome, it is found that the four cruciferous plants share some differentially expressed genes (DEG), but also have a considerable number of DEGs showing species specificity; however, six Arabidopsis lines with very different genetic backgrounds and geographic origins have a high response to flg22 Conservative. However, the differences in the response to flg22 among cruciferous species are not consistent with their phylogeny. The researchers further found that WRKY transcription factor binding sites are enriched in the 5′-cis regulatory region of the species-specific flg22 response gene, which may drive the evolution of species-specific gene transcription. At the same time, the study also found that there is no correlation between the sequence differences in the coding region and the transcriptome differences, and the purification selection may maintain the conservation of the 5′-regulatory region of the flg22 response gene shared by cruciferous plants. In addition, the research results also show that the metabolome of different cruciferous plants after flg22 treatment is species-specific.
researchers say that the findings of this study reveal the evolutionary mechanism of gene transcription during PTI in cruciferous plants, in order to further understand the transcription level of plants under biological stress The evolutionary mechanism provides clues.
Plants recognize surrounding microbes by sensing microbe-associated molecular patterns (MAMPs) to activate pattern-triggered immunity (PTI). Despite their significance for microbial control, the evolution of PTI responses remains largely uncharacterized. Here, by employing comparative transcriptomics of six Arabidopsis thaliana accessions and three additional Brassicaceae species to investigate PTI responses, we identified a set of genes that commonly respond to the MAMP flg22 and genes that exhibit species-specific expression signatures. Variation in flg22-triggered transcriptome responses across Brassicaceae species was incongruent with their phylogeny, while expression changes were strongly conserved within A. thaliana. We found the enrichment of WRKY trans< em/>cription factor binding sites in the 5′-regulatory regions of conserved and species-specific responsive genes, linking the emergence of WRKY-binding sites with the evolution of gene expression patterns during PTI. Our findings advance our understanding of the evolution of the transcrip tome during biotic stress.