Genome-Wide Identification and Analysis of the Aureochrome Gene Family in Saccharina japonica and a Comparative Analysis with Six Other Algae

Abstract

Aureochrome (AUREO) is a kind of blue light photoreceptor with both LOV and bZIP structural domains, identified only in Stramenopiles. It functions as a transcription factor that responds to blue light, playing diverse roles in the growth, development, and reproduction of Stramenopiles. Most of its functions are currently unknown, especially in the economically important alga S. japonica farmed on a large scale. This study provided a comprehensive analysis of the characteristics of AUREO gene families in seven algae, focusing on the AUREOs of S. japonica. AUREO genes were strictly identified from seven algal genomes. Then AUREO phylogenetic tree was constructed from 44 conserved AUREO genes collected. These AUREO genes were divided into five groups based on phylogenetic relationships. A total of 28 genes unnamed previously were named according to the phylogenetic tree. A large number of different cis-acting elements, especially bZIP transcription factors, were discovered upstream of AUREO genes in brown algae. Different intron/exon structural patterns were identified among all AUREOs. Transcriptomic data indicated that the expression of Sj AUREO varied significantly during the different development stages of S. japonica gametophytes. Periodic rhythms of light induction experiments indicate that Sj AUREO existed in a light-dependent circadian expression pattern, differing from other similar studies in the past. This may indicate that blue light affects gametophyte development through AUREO as a light signal receptor. This study systematically identified and analyzed the AUREO gene family in seven representative brown algae, which lay a good foundation for further study and understanding of AUERO functions in agal growth and development.

More than a photoreceptor: aureochromes are intrinsic to the diatom light-regulated transcriptional network

“…In the case of diatoms, P. tricornutum is a versatile study subject, yet not representative for the dominant diatom species found in the world oceans. Recent studies on Nannochloropsis oceanica ( Poliner et al , 2022 ) and the brown seaweed Saccharina japonica (sweet kelp) ( Wu et al , 2022 ) are starting to address this, but major stramenopile lineages with diverse lifestyles have yet to be investigated. The recent expansions in molecular tools and sequencing resources for ecologically important stramenopile species will allow us to compare the light regulatory machineries of diatoms and other stramenopiles evolved in a diversity of light fields, such as the polar diatom Fragilariopsis cylindrus that is subjected to prolonged periods of darkness.…”

Genome-Wide Identification and Analysis of the Cryptochrome/Photolyase Family in brown algae Saccharina japonica

“…Analysis of gene families was mainly carried out with reference to an earlier paper (Wu et al, 2022). All network addresses needed for online analysis are summarized in Supplement Table . 3.…”

“…The differential expression changes of Sj CPFs in different developmental stages of S. japonica gametophyte were derived from transcriptome data (PRJNA816677) reported by Wu et al (2022). Transcriptome data are divided into four distinct stages according to different time points during gametophyte development: Dormant period (0 d), Vegetative growth period (3 d), Vegetative growth peak (6 d), and Gametogenesis period (9 d).…”