Streptophyte algae and the evolution of nuclear control over plastid function
Final Report Abstract
The results obtained in course of this project represent the first global analysis of the molecular stress responses of streptophyte algae challenged with cold and high light stress. The responses towards these stressors were evaluated by generating global differential gene expression data on one representative species of each of the six major classes of streptophyte algae. Of particular interest during these analyses were plastid-associated gene expression patterns. Along these lines, an assessment of transcript investment into genes coding for the predicted plastid proteome and plastid-associated processes was performed based on targeting predictions as well as homology inferences. These investment analyses revealed that those streptophyte algae that are phylogenetically closer to land plants spend their plastid-associated transcript budget in a specific distribution. Further, Zygnema circumcarinatum - which was the streptophyte algal species in this data set that is phylogenetically closest to land plants - was found to invest the highest transcript budget into plastid function. Next to plastid-associated gene expression patterns, general stress response circuits conserved between streptophyte algae and land plants were highlighted by the data; again did Zygnema circumcarinatum stand out: only the Zygnema circumcarinatum transcriptome featured transcripts coding for a putative receptor of the stress phytohormone abscisic acid. This is an important finding, as it was previously assumed that the genes for this critical first step in the abscisic signalling cascade evolved at the base of the land plants. The functional conservation of this receptor now stands to be tested. In sum, the data generated here revealed insights into the conservation of plastid and stress response circuits. This has provided us with multiple candidate genes and pathways that open up opportunities for future research.
Publications
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How embryophytic is the biosynthesis of phenylpropanoids and their derivatives in streptophyte algae? Plant Cell Physiol 58:934-945. (2017)
de Vries J, de Vries S, Slamovits CH, Rose LE, Archibald JM
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The carboxy terminus of YCF1 contains a motif conserved throughout >500 million years of streptophyte evolution. Genome Biol Evol 9:473-479. (2017)
de Vries J, Archibald JM, Gould SB
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Embryophyte stress signaling evolved in the algal progenitors of land plants. Proc Natl Acad Sci USA 115:E3471-E3480. (2018)
de Vries J, Curtis BA, Gould SB, Archibald JM
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Plant evolution: landmarks on the path to terrestrial life. New Phytol 217:1428–1434. (2018)
de Vries J, Archibald JM
