bioRxiv Science⌕ Search

Biology subjects

Wang, W.-M.

Publications and source records attributed to Wang, W.-M..

4 recordsLinked to original sources

Telomere-to-telomere sheep genome assembly reveals new variants associated with wool fineness trait

Ongoing efforts to improve sheep reference genome assemblies still leave many gaps and incomplete regions, resulting in a few common failures and errors in sheep genomic studies. Here, we report a complete, gap-free telomere-to-telomere (T2T) genome of a ram (T2T-sheep1.0) with a size of 2.85 Gb, including all autosomes and chromosomes X and Y. It adds 220.05 Mb of previously unresolved regions (PURs) and 754 new genes to the most updated reference assembly, ARS-UI_Ramb_v3.0, and contains four types of repeat units (SatI, SatII, SatIII, and CenY) in the centromeric regions. T2T-sheep1.0 exhibits a base accuracy of >99.999%, corrects several structural errors in previous reference assemblies, and improves structural variant (SV) detection in repetitive sequences. We identified 192,265 SVs, including 16,885 new SVs in the PURs, from the PacBio long-read sequences of 18 global representative sheep. With the whole-genome short-read sequences of 810 wild and domestic sheep representing 158 global populations and seven wild species, the use of T2T-sheep1.0 as the reference genome has improved population genetic analysis based on [~]133.31 million SNPs and 1,265,266 SVs, including 2,664,979 novel SNPs and 196,471 novel SVs. T2T-sheep1.0 improves selective tests by detecting several novel genes and variants, including those associated with domestication (e.g., ABCC4) and selection for the wool fineness trait (e.g., FOXQ1) in tandemly duplicated regions.

genomics↗

Pathogen effector-associated nuclear-localization of RPW8.2 amplifies its expression to boost immunity in Arabidopsis

RESISTANCE TO POWDERY MILDEW 8 (RPW8) defines a unique N-terminal coiled-coil domain of nucleotide-binding and leucine-rich repeat immune receptors required for immune signaling in plants. Arabidopsis RPW8.2 is specifically induced by the powdery mildew (PM) fungus (Golovinomyces cichoracearum) in the infected epidermal cells to activate immunity. The mechanism of RPW8.2-induction is not well understood. Here, we identify a G. cichoracearum factor delivered to the nucleus of the host cell, named Gc-RPW8.2 interacting protein 1 (GcR8IP1). Ectopic expression of GcR8IP1 in Arabidopsis or Nicotiana benthamiana suppressed host immune responses and enhanced susceptibility to PM. Host-induced gene silencing of GcR8IP1 compromised PM infectivity in susceptible Arabidopsis plants. Co-expression of GcR8IP1 with RPW8.2 increased nuclear localization of RPW8.2, which in turn, promoted transcriptional amplification of RPW8.2. Thus, RPW8.2-dependent defense strengthening is due to altered partitioning of RPW8.2 by an effector of a PM fungus, which exemplifies an atypical form of effector-triggered immunity.

plant biology↗

Insights into the susceptibility of rice to a floral disease

Crop floral diseases are economically important as they reduce grain yield and quality and even introduce food toxins. Rice false smut has emerged as a serious floral disease producing mycotoxins. However, very little is known on the interaction mechanisms between rice flower and the causal fungus Ustilaginoidea virens. Here we show that a conserved anti-fungal immunity in rice flower is disarmed by U. virens via a secreted protein UvChi1. UvChi1 functioned as an essential virulence factor and directly interacted with the chitin receptor CEBiP and co-receptor CERK1 in rice to disrupt their oligomerizations and subsequent immune responses. Moreover, intraspecific-conserved UvChi1 could target OsCEBiP/OsCERK1 receptor complex in at least 98.5% of 5232 surveyed rice accessions. These results demonstrate that U. virens utilizes a crucial virulence factor to subvert chitin-triggered flower immunity in most rice varieties, providing new insights into the susceptibility of rice to false smut disease. One Sentence SummaryThe fungal pathogen Ustilaginoidea virens disarms chitin-triggered immunity in rice flower via a secreted chitinase.

plant biology↗

Proteasome maturation factor UMP1 confers broad-spectrum disease resistance by modulating H2O2 accumulation in rice

Crops with broad-spectrum resistance (BSR) to diseases are highly desirable in agricultural production. Identification of BSR loci and dissection of the underlying mechanisms are fundamental for crop resistance breeding. Here, we describe the identification and characterization of a rice UMP1 allele, which confers race-nonspecific BSR against blast pathogen Magnaporthe oryzae. OsUMP1 encodes a proteasome maturation factor that contributes to 26S proteasome abundance and activity in rice. Modulation of OsUMP1 expression leads to proteome changes, particularly affects the amounts and activities of H2O2-degrading enzymes. Consequently, H2O2 accumulation and disease resistance are enhanced in OsUMP1-overexpressing rice but reduced in loss-of-function mutants. Elevation of OsUMP1 expression also promotes rice resistance to foliar pathogens Rhizoctonia solani and Xanthomonas oryzae pv. oryzae and a floral pathogen Ustilaginoidea virens without observable yield penalty. These results indicate a BSR pathway linking the proteasome machinery and H2O2 homeostasis, and provide a candidate gene for balancing BSR and yield traits in rice breeding. One Sentence SummaryA natural allele of rice UMP1 promotes resistance to multiple pathogens by boosting H2O2 accumulation.

plant biology↗