First report of Watermelon silver mottle orthotospovirus infecting Siraitia grosvenorii in China.

Siraitia grosvenorii, known as "Luohanguo or monk fruit", is a perennial vine belonging to the family Cucurbitaceae. It is cultivated for its fruits, which are used as a Chinese traditional medicine to treat throat, lung and intestine ailments, or as raw material to extract sweet cucurbitane-glycosides as sugar substitute sweeteners (Chen et al., 2007). The production of S. grosvenorii is limited by viral diseases especially cucumber green mottle mosaic virus (CGMMV), papaya ringspot virus (PRSV), watermelon mosaic virus, and zucchini yellow mosaic virus (Liao et al., 2005; Xie et al., 2020). In 2022, virus-like disease consisting of leaf mottling, crinkling, and ringspot was observed on S. grosvenorii plants grown in an insect-proof greenhouse in Guilin City, Guangxi Province, China, with an incidence rate of ~17%. High-throughput sequencing (HTS) was applied to identify potential viruses in the diseased plants. Briefly, total RNA was extracted from a pool of 28 leaf samples (with or without symptoms) of S. grosvenorii using Trizol reagent according to manufacturer's instructions (Invitrogen, U.S.A.). The rRNA was depleted (Epicentre Ribo-zero™ rRNA Removal Kit, Epicentre, U.S.A.), before steps of cDNA library construction (NEBNext® Ultra™ Directional RNA Library Prep Kit for Illumina®, NEB, U.S.A.), and sequencing (Hiseq 4000 platform, Illumina, U.S.A.). The subsequent bioinformatics analyses were performed according to Liu et al. (2021). HTS of the sample and raw reads processing resulted in 8.4 Gb clean data. The clean reads (150 bp) were de novo assembled into 87,414 contigs (≥200 bp), using CLC Genomics Workbench 21 (Qiagen, Germany). The contigs were annotated by local BLASTX, resulting in matches to CGMMV, PRSV, and watermelon silver mottle virus (WSMoV). Three contigs of 6,557 bp, 4,950 bp, and 3,594 bp were most identical to L (GenBank accession no. JX177647), M (MW051789), and S (KM242056) segments of WSMoV. The complete genome sequences corresponding to the contigs derived from the sample (designated as GL-1 variant of WSMoV, OQ401466-OQ401468) were obtained by reads mapping to segments of these isolates. The reads coverage was ≥99.75% in each RNA segment and the depth of the coverage was in a range of 74-285. To detect the presence of GL-1 in S. grosvenorii plants, three primer pairs D7280F/D7382R (5'-TGATAGCCTGATGAACACCA/5'-TGTCTCTAAACCTTCTACCGC, Tm = 55℃, product size 172 bp), D4512F/D4703R (5'-GCATTGAACTCGCTCACAC/5'-AGTAGACGACCCTGAAGACCT, Tm = 55℃, 192 bp), and D109F/D451R (5'-TTATGGCACAAGAGACAACAGAG/5'-GGGCGTTATGTTCAGTATATTGG, Tm = 56℃, 342 bp) were designed in the L, M, and S segments, respectively. Fresh symptomatic and asymptomatic leaf tissues (n=38) were collected from three fields and their extracted nucleic acids were individually tested with the primers designed by two-steps RT-PCR using TaKaRa RNA PCR kit Ver.3.0 (Takara, Japan). Expected amplicons were obtained in symptomatic samples (n=7) showing mottling, crinkling, and chlorosis. Other samples (n=31) with or without symptoms were negative to WSMoV infection. The amplicons were sequenced, and the sequences obtained shared >99% nt identities with the corresponding GL-1 sequences in GenBank. This is the first report of WSMoV on S. grosvenorii, which provides the basic information for virus disease management.

Dnah9 mutant mice and organoid models recapitulate the clinical features of patients with PCD and provide an excellent platform for drug screening.

Primary cilia dyskinesia (PCD) is a rare genetic disease caused by ciliary structural or functional defects. It causes severe outcomes in patients, including recurrent upper and lower airway infections, progressive lung failure, and randomization of heterotaxy. To date, although 50 genes have been shown to be responsible for PCD, the etiology remains elusive. Meanwhile, owing to the lack of a model mimicking the pathogenesis that can be used as a drug screening platform, thereby slowing the development of related therapies. In the current study, we identified compound mutation of DNAH9 in a patient with PCD with the following clinical features: recurrent respiratory tract infections, low lung function, and ultrastructural defects of the outer dynein arms (ODAs). Bioinformatic analysis, structure simulation assay, and western blot analysis showed that the mutations affected the structure and expression of DNAH9 protein. Dnah9 knock-down (KD) mice recapitulated the patient phenotypes, including low lung function, mucin accumulation, and increased immune cell infiltration. Immunostaining, western blot, and co-immunoprecipitation analyses were performed to clarify that DNAH9 interacted with CCDC114/GAS8 and diminished their protein levels. Furthermore, we constructed an airway organoid of Dnah9 KD mice and discovered that it could mimic the key features of the PCD phenotypes. We then used organoid as a drug screening model to identify mitochondrial-targeting drugs that can partially elevate cilia beating in Dnah9 KD organoid. Collectively, our results demonstrated that Dnah9 KD mice and an organoid model can recapture the clinical features of patients with PCD and provide an excellent drug screening platform for human ciliopathies.