Gene Expression Profiling Using cDNA Microarray Analysis of the Sexual Reproduction Stage of the Unicellular Charophycean Alga Closterium peracerosum-strigosum-littorale Complex

Abstract

The desmid Closterium peracerosum-strigosum-littorale complex, which is the closest unicellular sister to land plants, is the best characterized of the charophycean green algae with respect to the process of sexual reproduction. To elucidate the molecular mechanism of intercellular communication during sexual reproduction, we created a normalized cDNA library from mixed cells of the sexual and the vegetative phases and generated a cDNA microarray. In total, 3,236 expressed sequence tags, which were classified into 1,615 nonredundant groups, were generated for cDNA microarray construction. Candidate genes for key factors involved in fertilization, such as those that encode putative receptor-like protein kinase, leucine-rich-repeat receptorlike protein, and sex pheromone homologs, were up-regulated during sexual reproduction and/or by the addition of the purified sex pheromones, and the expression patterns of these genes were confirmed by quantitative real-time polymerase chain reaction analysis. This first transcriptome profile of Closterium will provide critical clues as to the mechanism and evolution of intercellular communication between the egg and sperm cells of land plants.

The genus Closterium, a new model organism to study sexual reproduction in streptophytes

“…Recently, we obtained RNA‐seq data from various stages in the life cycle of homothallic strains (unpublished). Some of the contigs showed high similarities to sex‐specific genes, which had been identified in the heterothallic strains by cDNA microarray analysis (Sekimoto et al ., ). We are now attempting to detect the transient expression of the genes and corresponding proteins in just‐divided sister gametangial cells.…”

Sexual Reproduction of a Unicellular Charophycean Alga, Closterium peracerosum-strogosum-littorale Complex

“…The aim was to reduce redundancy, and 3,236 ESTs were generated, which were classifi ed into 1,615 nonredundant groups Sekimoto et al 2006 ). The EST sequences were compared with nonredundant protein sequence databases in the public domain using the BLASTX program, and 1,045 nonredundant sequences displaying similarity to previously registered genes in the public databases were confi rmed.…”

CRISPR/Cas9-based knockouts reveal that CpRLP1 is a negative regulator of the sex pheromone PR-IP in the Closterium peracerosum-strigosum-littorale complex

“…A cDNA microarray analysis revealed 88 pheromone-inducible, conjugation-related and/or sex-specific genes 15 . Among them, we focused on two genes named CpRLK1 and CpRLP1 because CpRLK1 encodes a receptor-like protein kinase (RLK), whereas CpRLP1 encodes a leucine-rich repeat (LRR) receptor-like protein (RLP).…”