Full-Length Transcriptome Characterization and Comparative Analysis of Chosenia arbutifolia

Analysis of full length transcriptome and resistance characteristics of Atraphaxis bracteata under drought

Drought is one of the main environmental factors affecting plant survival and growth. Atraphaxis bracteata is a common desert plant mainly utilized in afforestation and desertification control. This study analyzed the morphological, physiological and molecular regulatory characteristics of different organs of A. bracteata under drought stress. The results showed that with the intensification of drought stress, the height, root length and leaf area of A. bracteata seedlings decreased, while the content of osmotic substances and antioxidant enzyme activity increased. Furthermore, a total of 63 907 non-redundant transcript sequences, of which 55 574 transcripts were annotated, 248 178 FLNC sequences, 107 112 high-quality consistent sequences and 291 314 CCSs were obtained from Iso-Seq. Meanwhile, a total of 2 039 AS events, 22 919 SSR, 40 404 CDS and 5 902 lncRNA were also obtained. The RNA-Seq analysis results revealed that a total of 2 821, 3 907 and 5 532 DETs were identified from roots, stems and leaves, respectively, and which had significantly enrichment in "circadian rhythm-plant" and "starch and sucrose metabolism" pathway. These results would be great significance for further research on the stress resistance of A. bracteata and these DETs function.

Full-length transcriptome characterization of Platycladus orientalis based on the PacBio platform

As a unique and native conifer in China, Platycladus orientalis is widely used in soil erosion control, garden landscapes, timber, and traditional Chinese medicine. However, due to the lack of reference genome and transcriptome, it is limited to the further molecular mechanism research and gene function mining. To develop a full-length reference transcriptome, tissues from five different parts of P. orientalis and four cone developmental stages were sequenced and analyzed by single-molecule real-time (SMRT) sequencing through the PacBio platform in this study. Overall, 37,111 isoforms were detected by PacBio with an N50 length of 2,317 nt, an average length of 1,999 bp, and the GC content of 41.81%. Meanwhile, 36,120 coding sequences, 5,645 simple sequence repeats (SSRs), 1,201 non-coding RNAs (lncRNAs), and 182 alternative splicing (AS) events with five types were identified using the results obtained from the PacBio transcript isoforms. Furthermore, 1,659 transcription factors (TFs) were detected and belonged to 51 TF families. A total of 35,689 transcripts (96.17%) were annotated through the NCBI nr, KOG, Swiss-Prot and KEGG databases, and 385 transcript isoforms related to 8 types of hormones were identified incorporated into plant hormone signal transduction pathways. The assembly and revelation of the full-length transcriptome of P. orientalis offer a pioneering insight for future investigations into gene function and genetic breeding within Platycladus species.

The whole-genome assembly of an endangered Salicaceae species: Chosenia arbutifolia (Pall.) A. Skv

BACKGROUND

As a fast-growing tree species, Chosenia arbutifolia has a unique but controversial taxonomic status in the family Salicaceae. Despite its importance as an industrial material, in ecological protection, and in landscaping, C. arbutifolia is seriously endangered in Northeast China because of artificial destruction and its low reproductive capability.

RESULTS

To clarify its phylogenetic relationships with other Salicaceae species, we assembled a high-quality chromosome-level genome of C. arbutifolia using PacBio High-Fidelity reads and Hi-C sequencing data, with a total size of 338.93 Mb and contig N50 of 1.68 Mb. Repetitive sequences, which accounted for 42.34% of the assembly length, were identified. In total, 33,229 protein-coding genes and 11,474 small noncoding RNAs were predicted. Phylogenetic analysis suggested that C. arbutifolia and poplars diverged approximately 15.3 million years ago, and a large interchromosomal recombination between C. arbutifolia and other Salicaceae species was discovered.

CONCLUSIONS

Our study provides insights into the genome architecture and systematic evolution of C. arbutifolia, as well as comprehensive information for germplasm protection and future functional genomic studies.