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Anthracnose is one of the most widespread and destructive diseases in grapes. Grape anthracnose can be caused by various Colletotrichum species, such as Colletotrichum gloeosporioides and Colletotrichum cuspidosporium. In recent years, Colletotrichum aenigma was reported as a causal agent of Grape anthracnose in China and South Korea. Peroxisome is an important organelle in eukaryotes, which plays a very important role in the growth, development, and pathogenicity of several plant-pathogenic fungal species i, but it has not been reported in C. aenigma. In this work, the peroxisome of C. aenigma was labeled with a fluorescent protein, using green fluorescent protein (GFP) and red fluorescent protein (DsRED and mCherry) as reporter genes. Via Agrobacterium tumefaciens-mediated transformation (AtMT), two fluorescent fusion vectors to mark the peroxisomes, with GFP and DsRED, respectively, were introduced into a wild-type strain of C. aenigma. In the transformants, bright dots of green or red fluorescence in hyphae and spores could be seen in the strains labeled peroxisome. The nuclei labeled by the same method showed bright round fluorescent spots. In addition, we also combined fluorescent protein labeling with chemical staining to show the localization more clearly. The ideal peroxisome and nuclear fluorescence-labeled C. aenigma strain was obtained, which provided a reference for the study of its growth, development, and pathogenicity. [ABSTRACT FROM AUTHOR]

Grape ripe rot (Colletotrichum viniferum) causes huge losses in grape production in vineyards in southern China. However, the molecular mechanism against ripe rot in grape species and the responsive genes implicated in these processes are relatively unknown. Here, we present the transcriptome analysis of berries from a C. viniferum-resistant species (Vitis davidii Föex). Uninfected berries at day zero were used as control samples (CK), an inoculation was made at day zero, and the berries were subsequently analyzed at 1 day, 3 days, and 7 days post inoculation (dpi), which exhibited a sequential disease-progression stage. There were a total of 1810 differentially expressed genes, including 1315 up-regulated and 495 down-regulated transcripts. At 7 dpi, these differentially expressed genes (DEGs) were predominantly enriched in berries. In addition, in C. viniferum-infected grape fruits at 7 dpi, considerable changes in gene expression were induced, and those up-regulated genes involved in MAPK cascade, calcium ion binding, and serine/threonine kinase activity were enriched. According to our KEGG pathway analysis, numerous enriched biological processes, such as plant–pathogen interaction, phenylpropanoid biosynthesis, and metabolism, were implicated in grape–fungus interactions. Our research also revealed alterations in the expression pattern of phenylalanine-pathway-related transcription factors (TFs) and genes. We proposed a model in which C. viniferum invasion produces intracellular and extracellular Ca2+ deregulation to stimulate the MAPK pathway to activate TFs' (WRKY, ERF, and MYB) up-regulation, thus initiating disease-resistant responses in the tolerant Vitis species. Our results offer comprehensive transcriptomic data about molecular responses in C. viniferum-infected grape, and these data will aid in understanding of processes underlying plant responses to C. viniferum. [ABSTRACT FROM AUTHOR]

Grapevine trunk diseases (GTDs) are the most destructive diseases in grape-growing regions worldwide. Black foot is one of the important GTDs affecting young vineyards and nurseries. This disease has not been reported in China. During 2017 and 2019, field surveys were carried out in the Guangxi, Hebei, Ningxia, Shanxi, and Xinjiang provinces of China. Incidence of plants with black foot symptoms was 0.1% to 1% in the surveyed vineyards. Plant samples with poorly developed shoots and canes, chlorotic leaves, and necrotic trunks or roots were collected from the five provinces. In total, 50 fungal isolates were obtained from symptomatic tissues. Based on morphological and multi-gene phylogenetic analyses, five species were identified as Cylindrocladiella lageniformis, Dactylonectria torresensis, D. macrodidyma, D. alcacerensis and Neonectria sp.1. Pathogenicity was assessed using young, healthy detached green shoots of grapevine 'Summer Black' and potted 3-month-old 'Summer Black' cuttings. Inoculated detached shoots developed necroses after 7 d, and inoculated cuttings after 80 d. Fungi were re-isolated from necrotic lesions. Among the five species, D. macrodidyma was the most aggressive. This is the first report of C. lageniformis, D. torresensis, D. macrodidyma, D. alcacerensis, and Neonectria sp. 1 associated with black foot in China. This study has enhanced knowledge of the fungi associated with black foot in China, and will assist development of control measures for this disease. [ABSTRACT FROM AUTHOR]

Grapevine trunk diseases have become one of the main threats to grape production worldwide, with Diaporthe species as an emerging group of pathogens in China. At present, relatively little is known about the taxonomy and genetic diversity of Chinese Diaporthe populations, including their relationships to other populations worldwide. Here, we conducted an extensive field survey in six provinces in China to identify and characterize Diaporthe species in grape vineyards. Ninety-four isolates were identified and analyzed using multi-locus phylogeny. The isolates belonged to eight species, including three novel taxa, Diaporthe guangxiensis (D. guangxiensis), Diaporthe hubeiensis (D. hubeiensis), Diaporthe viniferae (D. viniferae) , and three new host records, Diaporthe gulyae (D. gulyae), Diaporthe pescicola (D. pescicola) , and Diaporthe unshiuensis (D. unshiuensis). The most commonly isolated species was Diaporthe eres (D. eres). In addition, high genetic diversity was observed for D. eres in Chinese vineyards. Haplotype network analysis of D. eres isolates from China and Europe showed a close relationship between samples from the two geographical locations and evidence for recombination. In comparative pathogenicity testing, D. gulyae was the most aggressive taxon, whereas D. hubeiensis was the least aggressive. This study provides new insights into the Diaporthe species associated with grapevines in China, and our results can be used to develop effective disease management strategies. [ABSTRACT FROM AUTHOR]

The Botryosphaeriaceae represents an important, cosmopolitan family of pathogens infecting woody plants. Grapevines (Vitis vinifera) suspected of being affected by Botryosphaeria dieback were collected from different Provinces of China and several Botryosphaeriaceae species were identified. This research was conducted to further study the species of Botryosphaeriaceae associated with grapevines in China and to estimate the prevalence and severity of the disease. Symptoms were characterized by partial or total death of grapevine cordons, with brown U-shaped necrotic sectors and brownish-black spots in cross-sections of affected trunks and arms. A fungus isolated from diseased vines in Henan and Anhui Provinces was identified as Neofusicoccum mangiferae on the basis of its morphological and cultural characteristics as well as an analysis of combined sequence data from the internal transcribed spacer (ITS) cluster of the ribosomal DNA together with partial sequences of the β-tubulin (BT) and translation elongation factor (EF1-α) genes. Pathogenicity was assessed by inoculating the fungus onto detached green grapevine shoots under controlled laboratory conditions and mature wood of standing vines cv. Summer Black in a greenhouse. This is the first record of N. mangiferae associated with grapevine dieback in the world. [ABSTRACT FROM AUTHOR]

To characterize the prevalence of viruses associated with grapevine leafroll disease in China, 249 grapevine (Vitis spp.) samples (86 popular cultivars and a rootstock) from 19 provinces and regions were collected and tested for Grapevine leafroll-associated virus 1 (GLRaV-1), GLRaV-2, GLRaV-3, GLRaV-4, and GLRaV-4 strain 5 by SYBR Green real-time reverse-transcription polymerase chain reaction (RTPCR), and RT-PCR and sequencing. GLRaV-3 was found in 100% of the samples while GLRaV-1, GLRaV-2, and GLRaV-4 were detected in 24.9% (62/249), 15.3% (38/249), and 0.80% (2/249) of the samples, respectively. Single infections with GLRaV-3 were found in 66.3% (165/249) of the samples, and the remaining samples were mixed infections of GLRaV-3 with one or two other GLRaVs, those with GLRaV-1 being the most common (18.5%, 46/249). The genetic variability of Chinese GLRaV-3 isolates was characterized based on the coat protein (CP) gene. In total, 153 full-length CP gene sequences (94 sequences newly generated) of Chinese GLRaV-3 isolates from different grapevine-growing regions showed 89.3 to 100.0% and 92.7 to 100.0% identity at the nucleotide and amino acid levels, respectively. The average nucleotide diversity for the population of Chinese GLRaV-3 isolates was estimated at 0.037 (standard error = 0.0032). GLRaV-3 isolates from China segregated into five distinct phylogenetic groups and two novel recombination events were found in the viral population. This is the first and most extensive report of the prevalent species of GLRaV in China, which also provides an assessment of genetic variability of GLRaV-3 Chinese isolates. [ABSTRACT FROM AUTHOR]

The black-foot disease of grapevine is one of the most destructive diseases in viticulture and it is caused by a complex of soil-borne fungi. This study aimed to identify the species associated with black-foot disease in young grapevines in vineyards of China. Fungal isolates were identified as Campylocarpon fasciculare, based on both morphological and multi-locus phylogenetic analysis of ITS, tef1–α and ß-tubulin sequence data. For the first time in China, we report Campylocarpon fasciculare associated with symptomatic young grapevines. Koch's postulates were performed on Vitis vinifera cv. Summer Black (SB) in a greenhouse and to confirm the pathogenicity on grapevines. This work improves the knowledge of black-foot disease in Chinese vineyards and will be helpful to growers in their decisions regarding vinicultural practices, planting and disease management. [ABSTRACT FROM AUTHOR]

Crown gall induced by Agrobacterium vitis is a worldwide plant disease in grape-growing regions. Rahnella aquatilis HX2, a new isolate from vineyard soil in Beijing, showed a significant inhibition effect on the development of crown galls in grapevines. In field trials, immersion of the basal ends of grape cuttings with HX2 cell suspension inhibited or completely prevented crown gall formation caused by A. vitis K308 in the roots of the plants from the cuttings. The 3-year average disease incidence in grape plants treated with HX2 was 30.8% compared to 93.5% in plants without HX2. The culture supernatant of HX2 exhibited a stronger inhibition effect on disease development than did the cell suspension. HX2 could be found in the grape rhizosphere, grown under field conditions, for up to 90 days after inoculation. There was no significant difference in the mean population sizes of root microflora between plants treated and not treated with HX2. The inhibition effect of HX2 on crown gall in sunflower, caused by different agrobacterial strains, varied between 30.7 and 100%, depending on strains. Our results showed that Rahnella aquatilis HX2 may be used as a biological control agent for crown gall disease of grapes. [ABSTRACT FROM AUTHOR]

Background: Virus disease is one of the main diseases in grapevine, and there has been no report on Plum bark necrosis and stem pitting-associated virus infecting grapevine in China. Objective: The leaf samples of grapevine cultivar 'Cabernet Gernischt' were collected from Shandong province, which the leaves suffered from viral-like symptoms with spotting and crinkle. Methods: Small RNA-seq combined with reverse transcription PCR (RT-PCR) were performed to detect the potential viruses in these field samples. Phylogenetic tree was constructed using the neighbor joining method in MEGA 5.1 Conclusions: This is the first report of PBNSPaV infecting grapevine in China, contributing to a better understanding of the epidemiology and host range distribution of this pathogen. [ABSTRACT FROM AUTHOR]

Grapevine berry inner necrosis virus (GINV) belongs to the genus Trichovirus in the family Betaflexiviridae. The GINV isolate LN_BETA_RS was obtained from a "Beta" grapevine (Vitis riparia × Vitis labrusca) exhibiting chlorotic mottling and ring spot in Xingcheng, Liaoning Province, China. To verify the correlation between GINV and grapevine chlorotic mottling and ring spot disease, we constructed an infectious cDNA clone of GINV isolate LN_BETA_RS using the seamless assembly approach. Applied treatments of agroinfiltration infectious cDNA confirmed systemic GINV infection of the Nicotianaoccidentalis 37B by reverse transcription polymerase chain reaction (RT-PCR) and transmission electron microscopy, exhibiting chlorotic mottling symptoms on leaves. Infectious cDNA was also transmitted to new healthy N. occidentalis plants through rub-inoculation. Moreover, the cDNA clone was agroinfiltrated into "Beta" and "Thompson Seedless" grapevine plantlets, and the inoculated grapevines exhibited leaf chlorotic mottling and ringspot during the two years of observation. GINV-inoculated "Beta" grapevines had serious leaf chlorotic mottling and ringspot symptoms on the whole plant, while relatively few symptoms were observed on the leaves of agroinoculated "Thompson Seedless" grapevines in early spring and only weak ring spot gradually appeared later in the top young leaves. Our experiments fulfilled Koch's postulates and revealed the causative role of GINV in grapevine chlorotic mottling and ring spot disease. [ABSTRACT FROM AUTHOR]