Abstract: The warm-season turfgrass seashore paspalum (Paspalum vaginatum) is rapidly gaining recognition as having a potentially important contribution in a range of turf and environment conservation applications. However, self-incompatibility (SI) creates issues for seed production in seashore paspalum, consequently limiting the feasibility of large scale planting. The mechanism of SI response in P. vaginatum is still largely unknown. In addition, the lack of genomic and transcriptomic information makes it highly challenging to clarify the mechanism of SI in seashore paspalum. In order to further understand the mechanism of SI in seashore paspalum, we created a self-compatible (SC) mutant (SP2008-3) and compared the first transcriptome of SI seashore paspalum (variety Adalayd) and the SC mutant using Illumina sequencing technology. Transcriptome analysis using RNA-sequencing was performed to profile gene expression patterns in Adalayd and SP2008-3 (the SC mutant). A total of 68.17 million raw reads were obtained, and de novo assembly produced 117619 Unigenes. All assembled Unigenes were annotated by querying against public databases. 58810 Unigenes (50%) were found to be homologous to genes in the NCBI non-redundant protein (Nr) database. In further orthologous analyses, comparison of the transcriptomes found 1303 Unigenes that showed significant differences in transcript abundance between Adalayd and SP2008-3. These Unigenes were functionally annotated within the Gene ontology (GO), Kyoto encyclopedia of genes and genomes (KEGG) pathways. A large number of notable genes potentially involved in SI responses showed differential expression. We conclude these genes may encode critical regulators of SI responses. Examples of these genes include 14 CaM (Calmodulin, calcium-dependent protein kinases and CBL-interacting protein kinases), 3 F-box and 5 THL (Thioredoxin). Our data represent a genetic resource for the discovery of genes related to SI in seashore paspalum. To our knowledge, this is the first study of the transcriptome of seashore paspalum focusing on SI. This resource will be very useful for future studies on the mechanisms of SI in seashore paspalum.

Key words: Seashore paspalum, self-incompatibility, transcriptome, differential expression gene