Biology subjects

Song, J.-M.

Publications and source records attributed to Song, J.-M..

3 recordsLinked to original sources

bioRxiv2021

Probing the Structural Basis of Citrus Phytochrome B using Computational Modelling and Molecular Dynamics Simulation Approaches

Phytochromes (Phys) are known as red/far-red light photoreceptors and are responsible for directing the photosensory responses across the species, majorly from fungal, bacterial and plant kingdoms. Such responses majorly include photosynthetic potential and pigmentation in bacteria, whereas in a plant, they are involved in chloroplast development and photomorphogenesis. Many prokaryotic Phys have been modelled for their structural and functional analysis, but their plant counterparts have not been explored yet. To date, only the crystal structures of the photo-sensing module (PSM) of PhyB isoform from Arabidopsis thaliana and Glycine max have been resolved experimentally. Thus, in this study, we elucidated the complete 3D structure of Citrus PhyB. Initially, the structure and organisation of the Citrus PhyB have been predicted computationally, which were found to have the same domain organisation as A. thaliana and G. max PhyBs, yet their considerable distinct structural difference indicated potential divergence in signaling and functioning. Therefore, to evaluate the structural and functional implications of Citrus PhyB, we compared its structure with A. thaliana and G. max PhyBs using molecular dynamics (MD) simulation approaches. The modeling studies revealed that the region of Citrus PhyB-GAF domain possibly contributes to the variations between Citrus, A. thaliana and G. max PhyBs structures/functions. Hence, structural and molecular insights into Citrus PhyB can help to discover the Phys signaling and thus, an essential framework can be designed for optogenetic reagents and various agricultural/horticulture benefits. One sentence summaryA complete Citrus PhyB structure together with photo-sensory and out-put modules provides significant information to evaluate its biological activities for agricultural benefits.

biophysics↗

bioRxiv2020

The gap-free rice genomes provide insights for centromere structure and function exploration and graph-based pan-genome construction

Rice (Oryza sativa), a major staple throughout the world and a model system for plant genomics and breeding, was the first crop genome completed almost two decades ago. However, all sequenced genomes to date contain gaps and missing sequences. Here, we report, for the first time, the assembly and analyses of two gap-free reference genome sequences of the elite O. sativa xian/indica rice varieties Zhenshan 97 (ZS97) and Minghui 63 (MH63) that are being used as a model system to study heterosis. Gap-free reference genomes also provide global insights into the structure and function of centromeres. All rice centromeric regions share conserved centromere-specific satellite motifs but with different copy numbers and structures. Importantly, we demonstrate that >1,500 genes are located in centromere regions, of which ~15.6% are actively transcribed. The generation and release of both the ZS97 and MH63 gap-free genomes lays a solid foundation for the comprehensive study of genome structure and function in plants and breed climate resilient varieties for the 21st century.

genomics↗

bioRxiv2020

Long-read sequencing reveals widespread intragenic structural variants in a recent allopolyploid crop plant

Genome structural variation (SV) contributes strongly to trait variation in eukaryotic species and may have an even higher functional significance than single nucleotide polymorphism (SNP). In recent years there have been a number of studies associating large, chromosomal scale SV ranging from hundreds of kilobases all the way up to a few megabases to key agronomic traits in plant genomes. However, there have been little or no efforts towards cataloging small (30 to 10,000 bp) to mid-scale (10,000 bp to 30,000 bp) SV and their impact on evolution and adaptation related traits in plants. This might be attributed to complex and highly-duplicated nature of plant genomes, which makes them difficult to assess using high-throughput genome screening methods. Here we describe how long-read sequencing technologies can overcome this problem, revealing a surprisingly high level of widespread, small to mid-scale SV in a major allopolyploid crop species, Brassica napus. We found that up to 10% of all genes were affected by small to mid-scale SV events. Nearly half of these SV events ranged between 100 bp to 1000 bp, which makes them challenging to detect using short read Illumina sequencing. Examples demonstrating the contribution of such SV towards eco-geographical adaptation and disease resistance in oilseed rape suggest that revisiting complex plant genomes using medium-coverage, long-read sequencing might reveal unexpected levels of functional gene variation, with major implications for trait regulation and crop improvement.

genomics↗