Two zinc finger proteins, VdZFP1 and VdZFP2, interact with VdCmr1 to promote melanized microsclerotia development and stress tolerance in Verticillium dahliae

BACKGROUND

Melanin plays important roles in morphological development, survival, host-pathogen interactions and in the virulence of phytopathogenic fungi. In Verticillum dahliae, increases in melanin are recognized as markers of maturation of microsclerotia which ensures the long-term survival and stress tolerance, while decreases in melanin are correlated with increased hyphal growth in the host. The conserved upstream components of the VdCmr1-regulated pathway controlling melanin production in V. dahliae have been extensively identified, but the direct activators of this pathway are still unclear.

RESULTS

We identified two genes encoding conserved C2H2-type zinc finger proteins VdZFP1 and VdZFP2 adjacent to VdPKS9, a gene encoding a negative regulator of both melanin biosynthesis and microsclerotia formation in V. dahliae. Both VdZFP1 and VdZFP2 were induced during microsclerotia development and were involved in melanin deposition. Their localization changed from cytoplasmic to nuclear in response to osmotic pressure. VdZFP1 and VdZFP2 act as modulators of microsclerotia melanization in V. dahliae, as confirmed by melanin biosynthesis inhibition and supplementation with the melanin pathway intermediate scytalone in albino strains. The results indicate that VdZFP1 and VdZFP2 participate in melanin biosynthesis by positively regulating VdCmr1. Based on the results obtained with yeast one- and two-hybrid (Y1H and Y2H) and bimolecular fluorescence complementation (BiFC) systems, we determined the melanin biosynthesis relies on the direct interactions among VdZFP1, VdZFP2 and VdCmr1, and these interactions occur on the cell walls of microsclerotia. Additionally, VdZFP1 and/or VdZFP2 mutants displayed increased sensitivity to stress factors rather than alterations in pathogenicity, reflecting the importance of melanin in stress tolerance of V. dahliae.

CONCLUSIONS

Our results revealed that VdZFP1 and VdZFP2 positively regulate VdCmr1 to promote melanin deposition during microsclerotia development, providing novel insight into the regulation of melanin biosynthesis in V. dahliae.

Species of the Colletotrichum spp., the Causal Agents of Leaf Spot on European Hornbeam (Carpinus betulus)

European hornbeam (Carpinus betulus L.) is widely planted in landscaping. In October 2021 and August 2022, leaf spot was observed on C. betulus in Xuzhou, Jiangsu Province, China. To identify the causal agent of anthracnose disease on C. betulus, 23 isolates were obtained from the symptomatic leaves. Based on ITS sequences and colony morphology, these isolates were divided into four Colletotrichum groups. Koch's postulates of four Colletotrichum species showed similar symptoms observed in the field. Combining the morphological characteristics and multi-gene phylogenetic analysis of the concatenated sequences of the internal transcribed spacer (ITS) gene, Apn2-Mat1-2 intergenic spacer (ApMat) gene, the calmodulin (CAL) gene, glyceraldehyde3-phosphate dehydrogenase (GAPDH) gene, Glutamine synthetase (GS) gene, and beta-tubulin 2 (TUB2) genes, the four Colletotrichum groups were identified as C. gloeosporioides, C. fructicola, C. aenigma, and C. siamense. This study is the first report of four Colletotrichum species causing leaf spot on European hornbeam in China, and it provides clear pathogen information for the further evaluation of the disease control strategies.

MrMYB44-Like Negatively Regulates Anthocyanin Biosynthesis and Causes Spring Leaf Color of Malus 'Radiant' to Fade From Red to Green

The "Spring-red-leaf" crabapple cultivar has young red leaves and mature green leaves. However, the mechanism of anthocyanin biosynthesis in crabapple leaves in spring remains unknown. In this study, Illumina RNA sequencing (RNA-Seq) was performed on Malus 'Radiant' leaf tissues in different stages of development. Twenty-two genes in the anthocyanin biosynthesis pathway and 44 MYB transcription factors (TFs) were significantly enriched among differentially expressed genes (DEGs). Three R2R3-MYB TFs in subgroup 22 of the MYB TF family, MrMYB44-like1, MrMYB44-like2, and MrMYB44-like3, were highly expressed in green leaves according to RNA-Seq and quantitative real-time quantitative PCR results. Their expression levels were negatively correlated with anthocyanin content. In transient assays, overexpression of MrMYB44-like1, MrMYB44-like2, or MrMYB44-like3 inhibited anthocyanin accumulation and reduced pigment in leaf disks of M. 'Radiant' and fruit peels of M. domestica 'Fuji.' When the conserved region of the three MrMYB44-likes was silenced, the anthocyanin biosynthesis pathway was activated and pigments increased in both tissues. Moreover, bimolecular fluorescence complementation assays showed MrMYB44-likes interacted with MrWRKY6 to form protein complexes that regulated anthocyanin biosynthesis.

Cyclocarya paliurus Reprograms the Flavonoid Biosynthesis Pathway Against Colletotrichum fructicola

Cyclocarya paliurus is an endemic Chinese tree species with considerable medicinal, timber, and horticultural value. The anthracnose disease of C. paliurus is caused by the fungal pathogen Colletotrichum fructicola, which results in great losses in yield and quality. Here, resistance evaluation of six cultivars of C. paliurus exhibited varying degrees of resistance to C. fructicola infection, where Wufeng was the most resistant and Jinggangshan was the most susceptive. Physiological measurements and histochemical staining assays showed that the Wufeng cultivar exhibits intense reactive oxygen species accumulation and defense capabilities. A multiomics approach using RNA sequencing and metabolome analyses showed that resistance in C. paliurus (Wufeng) is related to early induction of reprogramming of the flavonoid biosynthesis pathway. In vitro antifungal assays revealed that the flavonoid extracts from resistant cultivars strongly inhibited C. fructicola hyphal growth than susceptible cultivars. Relative gene expression analysis further demonstrated the pivotal antifungal role of C. paliurus flavonoids in targeting Colletotrichum appressorium formation. Together, these results represent a novel resistance mechanism of C. paliurus against anthracnose through the reprogramming of flavonoids, which will lay a foundation for breeding anthracnose-resistant varieties and the application of flavonoid extraction of C. paliurus as a natural antifungal treatment.

[Neurofeedback therapy in the treatment of tinnitus]

Neurofeedback therapy is a fast-growing field of tinnitus treatment, which is a new type of biofeedback therapy. In the past, the "muscle tone" and "blood flow" were used as feedback signals in biofeedback therapy to treat tinnitus, however there was no long-term follow-up report. Instead, neurofeedback therapy utilizes EEG (electroencephalogram) as the feedback signal, which is also called EEG biofeedback therapy. At present, most treatments of tinnitus only record subjective measures of patients as evaluation indicators, whereas neurofeedback therapy is more convincing for using comprehensive evaluation including changes of brain wave as objective indicators and subjective measures of patients. A significant number of tinnitus patients have varying degree of hearing loss. As neurofeedback therapy takes advantage of EEG as feedback signal that is delivered to the patients through visual information, it has unique advantages of being not affected by the degree of hearing loss compared to the sound masking or other sound treatment. Long-term follow-up results showed that the efficacy of neurofeedback therapy was stable after half a year of short-term treatment. This paper summarizes the progress of the various types of biofeedback therapy in the treatment of tinnitus, and focuses on the neurofeedback therapy for the mechanism, indication, process, efficacy evaluation, defect and prospect of neurofeedback therapy in tinnitus treatment in order to help promote the development of domestic clinical neurofeedback therapy in tinnitus.

Flow cytometer analysis of cell apoptosis of endometrial carcinoma with Wnt10b

The aim of this study is to analyze the cell apoptosis of endometrial carcinoma (EC) with Wnt10b by Fluorescence Activated Cell Sorting (FACS) technology. AN3CA cell lines and Ishikawa-H-12 cell lines were taken as the in-vitro cell models to observe the influence of Wnt10b on key factors of Wnt signal pathway. Methyl thiazolyl tetrazolium (MTT) was applied for the detection of cell proliferation while FACS was used for the detection of cell apoptosis. Data were analyzed using statistical software SPSS14.0. After the overexpression of Wntl0b in AN3CA cells, the apoptosis rate dropped significantly compared with the two control groups (p < 0.05); while the apoptosis rate increased significantly compared with the control groups (p < 0.01) after Wntl0b knock-off in Ishikawa3-H-12 cells. In normal endometrium, Wnt10b gene expression was negative, while that in EC cells was positive. It can be concluded that Wnt10b gene can promote EC cell proliferation and inhibit its apoptosis.

A kinetic model for simulation of blood coagulation and inhibition in the intrinsic path

A mathematical simulation pathway for the generation of thrombin has been developed with various assumptions made of kinetic rate laws and their summation for reactions involving the activation of factors VIII, IX, X and V and protein C in the formation of thrombin. The object of the computational modelling study is to stimulate the activation and inhibition of blood coagulation. The level of complexity and assumed parameters makes conclusions uncertain. However, an interesting outcome is that kinetic rates may show oscillation behavior under particular high levels of protein C feedback inhibition. The model, which permits the assessment of the reaction over a broad range of conditions, would defy quantitative practical use, but could have predictive value as a qualitative descriptor of coagulation.

Finding keywords for intergenic and gene regions for human genome

The analysis of functionally related sequences for conserved patterns is important for further research of different functional regions. This paper presents an analysis of genes and intergenic sequences from the point of view of linguistics analysis, where gene and intergenic regions are regarded as two different subjects written in the four-letter alphabet [A, C, G, T] and high-frequency simple sequences are taken as keywords. A measurement alpha[l(tau)] was introduced to describe the relative repeat ratio of simple sequences. Cutoff values were found for keywords selection. After eliminating "noise," 87 short sequences were selected as keywords for intergenic regions and 76 for gene regions.

SVM classification of human intergenic and gene sequences

Despite constant improvement in prediction accuracy, gene-finding programs are still unable to provide automatic gene discovery with the desired correctness. This paper presents an analysis of gene and intergenic sequences from the point of view of language analysis, where gene and intergenic regions are regarded as two different subjects written in the four-letter alphabet {A,C,G,T}, and high frequency simple sequences are taken as keywords. A measurement alpha(l(tau)) was introduced to describe the relative repeat ratio of simple sequences. Threshold values were found for keyword selections. After eliminating 'noise', 178 short sequences were selected as keywords. DNA sequences are mapped to 178-dimensional Euclidean space, and SVM was used for prediction of gene regions. We showed by cross-validation that the program we developed could predict 93% of gene sequences with 7% false positives. When tested on a long genomic multi-gene sequence, our method improved nucleotide level specificity by 21%, and over 60% of predicted genes corresponded to actual genes.

The kinetic model and simulation of blood coagulation—the kinetic influence of activated protein C

The paper described a limited part of the coagulation pathway, and in particular the inhibitory effects of activated protein C in the context of thrombin production. This is a computational modeling study with various assumption made of kinetic rates laws and their summation. The level of complexity and assumed parameters makes conclusions uncertain. However, an interesting outcome is that kinetic reaction rates may show oscillation behavior under particular, high levels of protein C feedback inhibition. The model would defy quantitative practical use, but could have predictive value as a qualitative descriptor of coagulation.

Role of phosphate and kinetic characteristics of complete iron release from native pig spleen ferritin-Fe

The kinetics for complete iron release showing biphasic behavior from pig spleen ferritin-Fe (PSFF) was measured by spectrophotometry. The native core within the PSFF shell consisted of 1682 hydroxide Fe3+ and 13 phosphate molecules. Inhibition kinetics for complete iron release was measure by differential spectrophotometry in the presence of phosphate; the process was clearly divided into two phases involving a first-order reaction at an increasing rate of 46.5 Fe3+/PSFF/min on the surface of the iron core and a zero-order reaction at a decreasing rate of 6.67 Fe3+/PSFF/min inside the core. The kinetic equation [C(PSFF-Fe3+)max - C(PSFF-Fe3+)t](1/2) = Tmax - Tt gives the transition time between the two rates and represents the complex kinetic characteristics. The rate was directly accelerated twofold by a mixed reducer of dithionite and ascorbic acid. These results suggest that the channel of the PSFF shell may carry out multiple functions for iron metabolism and storage and that the phosphate strongly affects the rate of iron release.