Chromosome-scale genome assembly of Prunus pusilliflora provides novel insights into genome evolution, disease resistance, and dormancy release in Cerasus L.

Prunus pusilliflora is a wild cherry germplasm resource distributed mainly in Southwest China. Despite its ornamental and economic value, a high-quality assembled P. pusilliflora genome is unavailable, hindering our understanding of its genetic background, population diversity, and evolutionary processes. Here, we de novo assembled a chromosome-scale P. pusilliflora genome using Oxford Nanopore, Illumina, and chromosome conformation capture sequencing. The assembled genome size was 309.62 Mb, with 76 scaffolds anchored to eight pseudochromosomes. We predicted 33 035 protein-coding genes, functionally annotated 98.27% of them, and identified repetitive sequences covering 49.08% of the genome. We found that P. pusilliflora is closely related to Prunus serrulata and Prunus yedoensis, having diverged from them ~41.8 million years ago. A comparative genomic analysis revealed that P. pusilliflora has 643 expanded and 1128 contracted gene families. Furthermore, we found that P. pusilliflora is more resistant to Colletotrichum viniferum, Phytophthora capsici, and Pseudomonas syringae pv. tomato (Pst) DC3000 infections than cultivated Prunus avium. P. pusilliflora also has considerably more nucleotide-binding site-type resistance gene analogs than P. avium, which explains its stronger disease resistance. The cytochrome P450 and WRKY families of 263 and 61 proteins were divided into 42 and 8 subfamilies respectively in P. pusilliflora. Furthermore, 81 MADS-box genes were identified in P. pusilliflora, accompanying expansions of the SVP and AGL15 subfamilies and loss of the TM3 subfamily. Our assembly of a high-quality P. pusilliflora genome will be valuable for further research on cherries and molecular breeding.

Dual domestications and origin of traits in grapevine evolution.

We elucidate grapevine evolution and domestication histories with 3525 cultivated and wild accessions worldwide. In the Pleistocene, harsh climate drove the separation of wild grape ecotypes caused by continuous habitat fragmentation. Then, domestication occurred concurrently about 11,000 years ago in Western Asia and the Caucasus to yield table and wine grapevines. The Western Asia domesticates dispersed into Europe with early farmers, introgressed with ancient wild western ecotypes, and subsequently diversified along human migration trails into muscat and unique western wine grape ancestries by the late Neolithic. Analyses of domestication traits also reveal new insights into selection for berry palatability, hermaphroditism, muscat flavor, and berry skin color. These data demonstrate the role of the grapevines in the early inception of agriculture across Eurasia.

A Comparative Analysis on the Structure and Function of the Panax notoginseng Rhizosphere Microbiome.

Panax notoginseng, an important Chinese medicinal herb, can be mainly cultivated in two planting patterns, cropland planting (DT) and understory planting (LX). We speculate that the rhizosphere microbiome may vary in DT and LX and may play an important role in promoting the growth and health of P. notoginseng. In the present study, culture-independent Illumina HiSeq was employed to investigate the rhizosphere bacteria and fungi under DT and LX planting patterns. Predominant phyla include Proteobacteria, Acidobacteria, Actinobacteria, Gemmatimonadetes, and Ascomycota in the two planting patterns. DT has higher alpha diversity index than LX. The predominant LX-core genera include Bradyrhizobium, Streptomyces, and Actinomadura, and the predominant DT-core genera include Sphingomonas, Variovorax, and Novosphingobium. Total relative abundance of the disease-suppression phylum (Proteobacteria, Firmicutes, and Actinobacteria) and the potential plant growth-promoting rhizobacteria (PGPR) were both significantly higher in LX than in DT. We also identified over-presented microbial functional traits mediating plant-microbe and microbe-microbe interactions, nutrition acquisition, and plant growth promotion in P. notoginseng rhizosphere. Our findings provide a valuable reference for studying beneficial microbes and pathogens of P. notoginseng planted in DT and LX.

SNHG8 is identified as a key regulator of epstein-barr virus(EBV)-associated gastric cancer by an integrative analysis of lncRNA and mRNA expression.

The Epstein-Barr virus (EBV) is associated with a variety of cancers, including gastric cancer, which has one of the highest mortality rates of all human cancers. Long non-coding RNAs (lncRNAs) have been suggested to have important causal roles in gastric cancer. However, the interaction between lncRNAs and EBV has not yet been studied. To this end, we sequenced 11,311 lncRNAs and 144,826 protein-coding transcripts from four types of tissue: one non-EBV-infected gastric carcinoma (EBVnGC) and its adjacent normal tissue, and one EBV-associated gastric carcinoma (EBVaGC) and its adjacent normal tissue. Five lncRNAs showed EBVaGC-specific expression; of those, one (SNHG8) was validated using real-time PCR in an independent cohort with 88 paired gastric cancer and adjacent tissue samples. To explore the functions of SNHG8, we identified its mRNA targets on the lncRNA-mRNA co-expression network of the Illumina Body Map, which contains the RNA sequencing data of mRNAs and lncRNAs from 16 normal human tissues. SNHG8 lncRNA was found to affect several gastric cancer-specific pathways and target genes of EBV. Our results reveal the intertwined tumorigenesis mechanisms of lncRNA and EBV and identify SNHG8 as a highly possible candidate biomarker and drug target of gastric cancer.