First Report of Passiflora latent virus in Passion fruit (Passiflora edulis) in China.

Passion fruit (Passilora edulis, family Passifloraceae.) is an economically important fruit crop in many tropical and subtropical regions worldwide. It is widely planting in southern China, and in greenhouses throughout the country. In Mar 2022, symptoms of a viral-like infection were observed on the leaves of passion fruit plants in a 3-hectare greenhouse complex in Hohhot, China. Chlorotic lesions were observed on leaves of two vines of passion fruit and symptomatic leaves developed chlorotic spots, followed by systemic leaf chlorosis and necrosis. Dark ringed spots emerged on the surface of matured fruits (Figure 1). To confirm infectivity, mechanical transmission of the virus was performed by grinding leaves from two symptomatic passion fruit vines in 0.1M phosphate buffer pH 7, and the resulting two samples were each used to rub-inoculate carborundum-dusted leaves of three healthy passion fruit seedlings. Newly emerging leaves of inoculated plants developed mild mosaic symptoms 30-days after inoculation. Three samples from each of the two original symptomatic plants and two samples from each inoculated seedling tested positive using a Passiflora latent virus (PLV) ELISA Kit (Creative Diagnostics, USA). To further confirm the virus identity, total RNA from leaf samples from one of the original greenhouse symptomatic plants and one of the inoculated seedlings were extracted using an TaKaRa MiniBEST Viral RNA Extraction Kit (Takara, Japan). The two RNA samples were subjected to reverse transcription-polymerase chain reaction (RT-PCR) tests with virus specific primers PLV-F (5'-ACACAAAACTGCGTGTTGGA-3') and PLV-R (5'-CAAGACCCACCTACCTCAGTGTG-3') (Cho et al., 2020). RT-PCR products of the expected 571 bp were obtained from both the original greenhouse sample and inoculated seedling. Amplicons were cloned into the pGEM-T Easy Vector, and two clones per sample were Sanger sequenced bidirectionally (Sangon Biotech, China), and the sequence of one clone from one of the original symptomatic sample was uploaded to NCBI (GenBank OP320922.1). This accession had 98% nucleotide sequence identity with a PLV isolate from Korea (GenBank: LC556232.1). RNA extracts from two asymptomatic samples tested negative for PLV with both ELISA and RT-PCR tests. We also tested the original symptomatic sample for common occurring passion fruit viruses, including passion fruit woodiness virus (PWV), cucumber mosaic virus (CMV), east asian passiflora virus (EAPV), telosma mosaic virus (TeMV), papaya leaf curl Guangdong virus (PaLCuGdV), and the RT-PCR results were negative for those viruses. However, based on the systemic leaf chlorosis and necrosis symptoms, we cannot preclude a mixed infestation of other viruses. PLV affects fruit quality and has high potential to reduce market value. To our knowledge, this is the first report of PLV in China, which could provide a reference basis to PLV identification, prevention and control. Acknowledgments This research was carried out with the support of Inner Mongolia Normal University High-level Talents Scientific Research Startup Project (Grant no. 2020YJRC010). Supplementary material Figure 1. Mottle, leaf distortion, puckering symptoms on old leaf (A), mild puckering symptom on young leaf (B), and ring-striped spots symptoms on fruit (C) of the PLV infected passion fruit plant in China.

Evolution and expression of genes encoding TCP transcription factors in Solanum tuberosum reveal the involvement of StTCP23 in plant defence.

BACKGROUND: The plant-specific Teosinte branched1/Cycloidea/Proliferating cell factor (TCP) family of transcription factors is involved in the regulation of cell growth and proliferation, performing diverse functions in plant growth and development. In addition, TCP transcription factors have recently been shown to be targets of pathogenic effectors and are likely to play a vital role in plant immunity. No comprehensive analysis of the TCP family members in potato (Solanum tuberosum L.) has been undertaken, however, and whether their functions are conserved in potato remains unknown. RESULTS: To assess TCP gene evolution in potato, we identified TCP-like genes in several publicly available databases. A total of 23 non-redundant TCP transcription factor-encoding genes were identified in the potato genome and subsequently subjected to a systematic analysis that included determination of their phylogenetic relationships, gene structures and expression profiles in different potato tissues under basal conditions and after hormone treatments. These assays also confirmed the function of the class I TCP StTCP23 in the regulation of plant growth and defence. CONCLUSIONS: This is the first genome-wide study including a systematic analysis of the StTCP gene family in potato. Identification of the possible functions of StTCPs in potato growth and defence provides valuable information for our understanding of the classification and functions of the TCP genes in potato.

Silencing of transcription factor encoding gene StTCP23 by small RNAs derived from the virulence modulating region of potato spindle tuber viroid is associated with symptom development in potato.

Viroids are small, non-protein-coding RNAs which can induce disease symptoms in a variety of plant species. Potato (Solanum tuberosum L.) is the natural host of Potato spindle tuber viroid (PSTVd) where infection results in stunting, distortion of leaves and tubers and yield loss. Replication of PSTVd is accompanied by the accumulation of viroid-derived small RNAs (sRNAs) proposed to play a central role in disease symptom development. Here we report that PSTVd sRNAs direct RNA silencing in potato against StTCP23, a member of the TCP (teosinte branched1/Cycloidea/Proliferating cell factor) transcription factor family genes that play an important role in plant growth and development as well as hormonal regulation, especially in responses to gibberellic acid (GA). The StTCP23 transcript has 21-nucleotide sequence complementarity in its 3' untranslated region with the virulence-modulating region (VMR) of PSTVd strain RG1, and was downregulated in PSTVd-infected potato plants. Analysis using 3' RNA ligase-mediated rapid amplification of cDNA ends (3' RLM RACE) confirmed cleavage of StTCP23 transcript at the expected sites within the complementarity with VMR-derived sRNAs. Expression of these VMR sRNA sequences as artificial miRNAs (amiRNAs) in transgenic potato plants resulted in phenotypes reminiscent of PSTVd-RG1-infected plants. Furthermore, the severity of the phenotypes displayed was correlated with the level of amiRNA accumulation and the degree of amiRNA-directed down-regulation of StTCP23. In addition, virus-induced gene silencing (VIGS) of StTCP23 in potato also resulted in PSTVd-like phenotypes. Consistent with the function of TCP family genes, amiRNA lines in which StTCP23 expression was silenced showed a decrease in GA levels as well as alterations to the expression of GA biosynthesis and signaling genes previously implicated in tuber development. Application of GA to the amiRNA plants minimized the PSTVd-like phenotypes. Taken together, our results indicate that sRNAs derived from the VMR of PSTVd-RG1 direct silencing of StTCP23 expression, thereby disrupting the signaling pathways regulating GA metabolism and leading to plant stunting and formation of small and spindle-shaped tubers.

Physiological and TMT-based proteomic analysis of oat early seedlings in response to alkali stress.

Oats are an important cereal crop worldwide, and they also serve as a phytoremediation crop to ameliorate salinized and alkalized soils. However, the mechanism of the oat response to alkali remains unclear. Physiological and tandem mass tag (TMT)-based proteomic analyses were employed to elucidate the mechanism of the oat response to alkali stress. Physiological and phenotypic data showed that oat root growth was inhibited more severely than shoot growth after alkali stress. In total, 164 proteins were up-regulated and 241 proteins were down-regulated in roots, and 93 proteins were up-regulated and 139 proteins were down-regulated in shoots. Under high pH stress, transmembrane proton transporters were down-regulated; conversely, organic acid synthesis related enzymes were increased. Transporters of N, P, Fe, Cu and Ca in addition to N assimilation enzymes in the root were highly increased. This result revealed that higher efficiency of P, Fe, Cu and Ca transport, especially higher efficiency of N intake and assimilation, greatly promoted oat root resistance to alkali stress. Furthermore, many resistance proteins, such as late embryogenesis abundant (LEA) mainly in shoots, GDSL esterase lipase mainly in roots, and WD40-like beta propeller repeat families, greatly accumulated to contribute to oat resistance to alkali stress. SIGNIFICANCE: In this study, physiological and tandem mass tag (TMT)-based proteomic analyses were employed to elucidate oats early seedlings in response to alkali stress. Many difference expression proteins were found involving in oats response to alkali stress. Also, higher efficiency transport of P, Fe, Cu, Ca and N greatly promoted oat resistance to alkali stress.

The Cardiac Sympathetic Nerve Activity in the Elderly Is Attenuated in the Right Lateral Decubitus Position.

Objectives: The aim of this study was to evaluate the effect of the supine, left lateral decubitus, and right lateral decubitus positions on autonomic nervous activity in elderly adults by using spectral analysis of heart rate variability (HRV). Method: Forty-five adults aged 73.6 ± 5.7 years were enrolled. After lying in the supine position, all participants moved to the lateral decubitus positions in a random order and maintained the positions for 10 min, while electrocardiographic data were recorded to measure HRV. Results: The lowest heart rate continued for 10 min when participants were in the left lateral decubitus position compared with the other two positions (p < .001), while the HRV indexes remained unchanged. The low-frequency HRV to high-frequency HRV ratio (LF/HF) for the right lateral decubitus position was significantly lower than that for the other positions. Discussion: The right lateral decubitus position may attenuate sympathetic nerve activity in elderly adults.

Blunted Autonomic Responses and Low-Grade Inflammation in Mongolian Adults Born at Low Birth Weight.

Low birth weight (LBW) has been considered as a risk factor for adult hypertension that is associated with deterioration of autonomic functions and low-grade inflammation. To explore the above effects of LBW, we measured blood pressure (BP) and heart rate variability during postural change from a supine position to a sitting position in 21 healthy Mongolian adults aged 23-34 years: 4 with LBW (birth weight < 2,500 g), 13 with normal birth weight (NBW, 2,500 g ≤ birth weight < 4,000 g), and 4 with high birth weight (HBW, ≥ 4,000 g). Mongolian population is known to have higher prevalence of hypertension. The ratio of low frequency (LF, 0.04-0.15 Hz) to high frequency components (HF, 0.15-0.40 Hz) was used as an index of sympathetic nerve activity, and HF was used as an index of parasympathetic nerve activity. In contrast to the NBW group, the LBW and HBW groups showed no significant increase in heart rate, systolic BP and LF/HF following postural change. We also measured blood cell counts and other blood parameters related to inflammation. After adjusting for age, BMI, sex and family history of hypertension, LBW was retained as an independent predictor only for higher counts of leukocytes (ß = -0.51, p < 0.05), basophils (ß = -0.62, p < 0.01), eosinophils (ß = -0.83, p < 0.001), and platelets (ß = -0.61, p < 0.05). We propose that LBW leads to blunted autonomic responses and low-grade inflammation in seemingly healthy Mongolian adults.

Tailored synthesis of amine N-halamine copolymerized polystyrene with capability of killing bacteria.

Novel amine N-halamine copolymerized polystyrene (ANHCPS) nanostructures were controllably fabricated as potent antibiotics by using the surfactant-free emulsion copolymerization for killing pathogenic bacteria. The morphology and size of the ANHCPS were well tailored by tuning reaction conditions such as monomer molar ratio, temperature, and copolymerization time. Effect of chlorination aging time on the oxidative chlorine content in the ANHCPS was established, and the oxidative chlorine content was determined by the modified iodometric/thiosulfate technique. Antibacterial behavior of the ANHCPS on bacterial strain was evaluated using Staphylococcus aureus and Escherichia coli as model pathogenic bacteria via the plate counting technique, inhibition zone study, and time-kill assay. Antimicrobial results illustrated that the ANHCPS possessed superior antibacterial capability of killing pathogenic bacteria. The destruction induced by the ANHCPS on bacterial surface structure was proven by using SEM technique. The effect of the oxidative chlorine content and morphology/size on the antimicrobial capability was constructed as well. This study provides us a novel approach for controllably synthesizing amine N-halamine polymers, and making them the potent candidates for killing bacteria or even the control of microorganism contamination.

N-halamine-decorated polystyrene nanoparticles based on 5-allylbarbituric acid: from controllable fabrication to bactericidal evaluation.

N-halamine-based antibacterial polystyrene nanoparticles with different particle size ranged from 91.5 nm to 562.5 nm were facilely fabricated by surfactant-free emulsion polymerization with 5-allylbarbituric acid served as N-halamine precursor. Effect of experimental parameters such as monomer concentration, initiator concentration, and ionic strength on particle size was investigated systematically. N-halamine-based antibacterial polystyrene nanoparticles showed enhanced antibacterial activity against both Gram-positive species Staphylococcus aureus and Gram-negative species Pseudomonas aeruginosa compared with bulk powder N-halamine. Biocidal activity of N-halamine-based antibacterial polystyrene nanoparticles can be tailored effectively by tuning particle size. Stability and bactericidal activity of N-halamine-based antibacterial polystyrene nanoparticles was detected as a function of extending period.