Global Transcriptome Profiles of 'Meyer' Zoysiagrass in Response to Cold Stress.

A long green period is essential for a turfgrass species with high ornamental value and a wide area of use. Zoysiagrasses (Zoysia spp. Willd.) are perennial turfgrass species popular in tropical, subtropical and temperate zones, possessing many properties necessary to be economically useful turfgrass. They do not have a long green period because of cold sensitivity. A main focus in zoysiagrass research is to develop cold tolerant cultivars. Understanding the cold response in zoysiagrass is a fundamental area of research. In the present study, 'Meyer' zoysiagrass (Zoysia japonica), a widely cultivated variety in the genus, is used. We employed RNA-Seq to investigate genome-wide gene expression profiles in leaves under cold stress (4°C). Using the Illumina sequencing platform, we obtained approximately 206 million high-quality paired-end reads from three libraries (0 h, 2 h, and 72 h cold treatment at 4°C). After de novo assembly and quantitative assessment, 46,412 unigenes were generated with an average length of 998 bp and an N50 of 1,522 bp. A total of 25,644 (55.2%) unigenes were annotated by alignment with public protein databases including NR, SwissProt, KEGG and KOG. Differentially expressed genes (DEGs) were investigated using the RPKM method. A total of 756 DEGs were identified between 0 h and 2 h-cold treatment, with 522 up-regulated and 234 down-regulated; and 5327 DEGs were identified between 0 h and 72 h-cold treatment, with 2453 up-regulated and 2874 down-regulated. The expression profile of 15 DEGs selected randomly was confirmed with qRT-PCR. The results suggest that cold stress can induce desiccation and oxidative stress, inhibit photosynthesis and substance transport. In response to the stress, genes involved in proline synthesis, in starch hydrolysis, in methionine and ascorbic acid metabolism, in SOD activity, and in DREBs response pathway were up-regulated. GA metabolism, ABA and JA stimulus response were affected under cold exposure. This is the first transcriptome sequencing of Z. japonica, providing a large set of sequence data as well as gene expression profiles under cold stress. It will improve our current understanding of the cold response of zoysiagrass and be beneficial in breeding research.

Transcriptome sequencing and characterization of Japanese scallop Patinopecten yessoensis from different shell color lines.

Shell color is an important trait that is used in breeding the Japanese scallop Patinopecten yessoensis, the most economically important scallop species in China. We constructed four transcriptome libraries from different shell color lines of P. yessoensis: the left and right shell mantles of ordinary strains of P. yessoensis and the left shell mantles of the 'Ivory' and 'Maple' strains. These four libraries were paired-end sequenced using the Illumina HiSeq 2000 platform and contained 54,802,692 sequences, 40,798,962 sequences, 74,019,262 sequences, and 44,466,166 sequences, respectively. A total of 214,087,082 expressed sequence tags were assembled into 73,522 unigenes with an average size of 1,163 bp. When the data were compared against the public Nr and Swiss-Prot databases using BlastX, nearly 30.55% (22,458) of the unigenes were significantly matched to known unique proteins. Gene Ontology annotation and pathway mapping analysis using the Kyoto Encyclopedia of Genes and Genomes categorized unigenes according to their diverse biological functions and processes and identified candidate genes that were potentially involved in growth, pigmentation, metal transcription, and immunity. Expression profile analysis was performed on all four libraries and many differentially expressed genes were identified. In addition, 5,772 simple sequence repeats were obtained from the P. yessoensis transcriptomes, and 464,197, 395,646, and 310,649 single nucleotide polymorphisms were revealed in the ordinary strains, the 'Ivory' strain, and the 'Maple' strain, respectively. These results provide valuable information for future genomic studies on P. yessoensis and improve our understanding of the molecular mechanisms involved in the growth, immunity, shell coloring, and shell biomineralization of this species. These resources also may be used in a variety of applications, such as trait mapping, marker-assisted breeding, studies of population genetics and genomics, and work on functional genomics.

The duck genome and transcriptome provide insight into an avian influenza virus reservoir species.

The duck (Anas platyrhynchos) is one of the principal natural hosts of influenza A viruses. We present the duck genome sequence and perform deep transcriptome analyses to investigate immune-related genes. Our data indicate that the duck possesses a contractive immune gene repertoire, as in chicken and zebra finch, and this repertoire has been shaped through lineage-specific duplications. We identify genes that are responsive to influenza A viruses using the lung transcriptomes of control ducks and ones that were infected with either a highly pathogenic (A/duck/Hubei/49/05) or a weakly pathogenic (A/goose/Hubei/65/05) H5N1 virus. Further, we show how the duck's defense mechanisms against influenza infection have been optimized through the diversification of its ß-defensin and butyrophilin-like repertoires. These analyses, in combination with the genomic and transcriptomic data, provide a resource for characterizing the interaction between host and influenza viruses.