Construction of full-length infectious cDNA clones of two Korean isolates of turnip mosaic virus breaking resistance in Brassica napus.

In this work, two new turnip mosaic virus (TuMV) strains (Canola-12 and Canola-14) overcoming resistance in canola (Brassica napus) were isolated from a B. napus sample that showed typical TuMV-like symptoms and was collected in the city of Gimcheon, South Korea, in 2020. The complete genome sequence was determined and an infectious clone was made for each isolate. Phylogenetic analysis indicated that the strains isolated from canola belonged to the World-B group. Both infectious clones, which used 35S and T7 promoters to drive expression, induced systemic symptoms in Nicotiana benthamiana and B. napus. To our knowledge, this is the first report of TuMV infecting B. napus in South Korea.

Construction of full-length infectious clones of turnip mosaic virus isolates infecting Perilla frutescens and genetic analysis of recently emerged strains in Korea.

Perilla is an annual herb with a unique aroma and taste that has been cultivated in Korea for hundreds of years. It has been widely cultivated in many Asian and European countries as a food and medicinal crop. Recently, several viruses have been reported to cause diseases in perilla in Korea, including turnip mosaic virus (TuMV), which is known as a brassica pathogen due to its significant damage to brassica crops. In this study, we determined the complete genome sequences of two new TuMV isolates originating from perilla in Korea. Full-length infectious cDNA clones of these two isolates were constructed, and their infectivity was tested by agroinfiltration of Nicotiana benthamiana and sap inoculation of Chinese cabbage and radish plants. In addition, we analyzed the phylogenetic relationship of six new Korean TuMV isolates to members of the four major groups. We also used RDP4 software to conduct recombination analysis of recent isolates from Korea, which provided new insight into the evolutionary relationships of Korean isolates of TuMV.

Identification and Characterization of Gonatobotryum apiculatum Causing Leaf Spot and Blight on Sinowilsonia henryi.

Sinowilsonia henryi is a rare and endangered plant, as well as an endemic species in China. In July 2018, leaf spot and blight disease was observed on S. henryi in Yichang, Hubei, China. A fungus isolated from disease tissues was identified as Gonatobotryum apiculatum based on morphology and sequence analyses of ITS and LSU regions. Phylogenetic analyses indicated that the species belongs to Dothioraceae (Dothideales). Morphologically, the species produced two distinct types of conidia from authentic media, both conidia were described here. Pathogenicity tests showed that the fungus is a pathogen causing leaf spots on S. henryi. This is the first report of leaf spot and blight disease on S. henryi caused by G. apiculatum in China.

Dietary zinc deficiency reduced growth performance, intestinal immune and physical barrier functions related to NF-κB, TOR, Nrf2, JNK and MLCK signaling pathway of young grass carp (Ctenopharyngodon idella).

Our study investigated the effects of dietary zinc (Zn) deficiency on growth performance, intestinal immune and physical barrier functions of young grass carp (Ctenopharyngodon idella). A total of 630 grass carp (244.14 ± 0.40 g) were fed graded levels of zinc lactate (10.71, 30.21, 49.84, 72.31, 92.56, 110.78 mg Zn/kg diet) and one zinc sulfate group (56.9 mg Zn/kg diet) for 60 days. At the end of the feeding trial, fish were challenged with Aeromonas hydrophila for 14 days. These results indicated that compared with optimal dietary Zn level, dietary Zn deficiency (10.71 mg/kg diet) decreased the production of antibacterial compounds, up-regulated pro-inflammatory cytokines related to nuclear factor kappa B (NF-κB) and down-regulated anti-inflammatory cytokines related to target of rapamycin (TOR) in three intestinal segments of young grass carp (P < 0.05), suggesting that dietary Zn deficiency could impair intestinal immune barrier of fish; decreased the activities and mRNA levels of antioxidant enzymes related to NF-E2-related factor 2 (Nrf2), up-regulated the mRNA levels of caspase-3, -7, -8, -9 related to p38 mitogen activated protein (p38 MAPK) and c-Jun N-terminal protein kinase (JNK), down-regulated the mRNA levels of tight junction complexes (TJs) related to myosin light chain kinase (MLCK) in three intestinal segments of young grass carp (P < 0.05), demonstrating that dietary Zn deficiency could injury intestinal physical barrier of fish. Besides, the Zn requirements (zinc lactate as Zn source) based on percent weight gain (PWG), against enteritis morbidity, acid phosphatase (ACP) activity in the proximal intestine (PI) and malondialdehyde (MDA) content in the PI of young grass carp was estimated to be 61.2, 61.4, 69.2 and 69.5 mg/kg diet, respectively. Finally, based on specific growth rate (SGR), feed efficiency (FE) and against enteritis morbidity of young grass carp, the efficacy of zinc lactate relative to zinc sulfate were 132.59%, 135.27% and 154.04%, respectively.