Fusarium pernambucanum Causing Peduncle Rot on Grape in Guangxi, China.

Grape (Vitis vinifera) is regarded as one of the most economically important fruit crops throughout the world and is widely cultivated in China. In March 2023, peduncle rot symptoms were observed on ripe grape (cv. Kyoho) of Guangxi Academy of Agricultural Sciences in Nanning, Guangxi Province (20°54' to 26°24' N, 104°26' to 112°04' E), causing severe shrink of infected grapes with incidence of 20 to 40%. Initially, a small portion of the grape peduncles turned from light brown to darker brown and gradually spread to the entire bunch of grape peduncles. Then the peduncles gradually dried up and became dark brown, resulting in necrosis and shedding of the fruits. Symptomatic peduncles were cut into small pieces (approximately 3 mm long), surface disinfected with 75% alcohol for 10 s, 1% NaOCl for 2 min followed by three washes in sterile distilled water and separately transferred to potato dextrose agar (PDA) plates. Forty-six Fusarium isolates were obtained from the seventy-five tissue pieces after 5 days of incubation at 25°C on PDA (average isolation frequency 61%). Based on the morphology, a representative isolate of Fusarium was selected for each of the three samples. Single spore isolates (PT1-1, PT3-1, and PT3-2) were selected for further study. The colonies produced abundant whitish to yellowish aerial mycelium on PDA after 7 days incubation at 25°C in the dark. Macroconidia cultured on carnation leaf agar (CLA) for 7 days were falcate, multiseptate, with a curved apical cell and foot-shaped basal cell, mostly 1-3-septate, measuring 21.3 ± 0.5 µm × 4.8 ± 0.1 µm, 24.3 ± 0.5 µm × 4.5 ± 0.1 µm, 21.9 ± 0.3 µm × 4.5 ± 0.1 µm (n=90) for PT1-1, PT3-1, and PT3-2, respectively. Microconidia were hyaline, fusoid or ovoid, 0- or 1-septate, measuring 10.5 ± 0.2 µm × 3.5 ± 0.1 µm, 10.4 ± 0.3 µm × 3.6 ± 0.1 µm, 10.0 ± 0.2 µm × 3.6 ± 0.1 µm (n=90) for PT1-1, PT3-1, and PT3-2, respectively. The internal transcribed spacer (ITS), translation elongation factor (TEF1), calmodulin (CAM) and partial RNA polymerase second largest subunit (RPB2) were amplified using primers ITS4/ITS1, EF1/EF2, CL1/CL2A, and 5F2/7cR, respectively (White et al. 1990; O'Donnell et al. 1998, 2000; Reeb et al. 2004; Liu et al. 1999). Sequences from the three isolates were deposited in GenBank (ITS: OR511756-OR511758; TEF1: OR535156-OR535158; CAM: OR535153-OR535155; RPB2: OR535159-OR535161). A maximum likelihood (ML) phylogenetic tree was constructed with RAxML version 8.2.10 based on the concatenated sequences (ITS, CAM, TEF1, RPB2). According to morphology and phylogenetic analysis, the isolates were identified as Fusarium pernambucanum (Santos et al. 2019). A pathogenicity test was performed with three isolates on twenty-four asymptomatic strings of grapes in a field in Nanning, Guangxi Province, China. On twelve strings of ripe grapes (cv. Kyoho), 3-mm-long wounds were made on the peduncle of each string of grapes with a sterile needle, followed by inoculation with conidial suspension (106spores/ml in 0.1% sterile Tween 20) by misting with an atomizer until runoff (Lorenz et al. 1995). Three isolates were separately inoculated onto three strings of grapes. Controls were inoculated with water containing 0.1% sterile Tween 20 under the same conditions. The same inoculation was applied to twelve strings of non-wound grapes. Plants were covered with polythene bags to maintain high humidity for 7 days. Typical dark brown lesions were observed on all inoculated peduncles with conidia. After 14 days, the necrotic lesions spread to the entire peduncles causing them to shrivel and die. No symptoms were observed on controls. Koch's postulates were completed by reisolating the fungus from the inoculated tissues. The results of morphological identification and multigene sequence analysis obtained by reisolation were consistent with original isolates. To our knowledge, this is the first report of F. pernambucanum causing peduncle rot on grape in China. These results will provide valuable information for prevention and management of peduncle rot on grape.

FOXD1 predicts prognosis of colorectal cancer patients and promotes colorectal cancer progression via the ERK 1/2 pathway.

Previous studies indicated a critical role of foxhead box D1 (FOXD1) in human cancers. However, its expression pattern in colorectal cancer (CRC) and the molecular mechanism of FOXD1 on cancer progression remain unknown. In this study, we found that FOXD1 was aberrantly overexpressed in human CRC tissues, and FOXD1 levels were correlated with tumor size, differentiation, TNM stage and lymph node metastasis and poor prognosis. Knockdown of FOXD1 attenuated CRC cell proliferation, migration and invasion. Overexpression of FOXD1 produced the opposite effects. These effects were mediated by activation of the ERK 1/2 signaling pathway, and inhibition of this pathway with a specific ERK 1/2 inhibitor (U0126) could impair the tumor-promoting effects induced by overexpression of FOXD1. Taken together, these findings indicate that FOXD1 promotes tumorgenesis and progression of CRC by activating ERK 1/2 signaling pathway and may represent a potential clinical target.

Emodin enhances the demethylation by 5-Aza-CdR of pancreatic cancer cell tumor-suppressor genes P16, RASSF1A and ppENK.

5-Aza-2'-deoxycytidine (5-Aza-CdR) is currently acknowledged as a demethylation drug, and causes a certain degree of demethylation in a variety of cancer cells, including pancreatic cancer cells. Emodin, a traditional Chinese medicine (TCM), is an effective monomer extracted from rhubarb and has been reported to exhibit antitumor activity in different manners in pancreatic cancer. In the present study, we examined whether emodin caused demethylation and increased the demethylation of three tumor-suppressor genes P16, RASSF1A and ppENK with a high degree of methylation in pancreatic cancer when combined with 5-Aza-CdR. Our research showed that emodin inhibited the growth of pancreatic cancer Panc-1 cells in a dose- and time-dependent manner. Dot-blot results showed that emodin combined with 5-Aza-CdR significantly suppressed the expression of genome 5mC in PANC-1 cells. In order to verify the effect of methylation, methylation-specific PCR (MSP) and bisulfite genomic sequencing PCR (BSP) combined with TA were selected for the cloning and sequencing. Results of MSP and BSP confirmed that emodin caused faint demethylation, and 5-Aza-CdR had a certain degree of demethylation. When emodin was combined with 5-Aza-CdR, the demethylation was more significant. At the same time, fluorescent quantitative PCR and western blot analysis results confirmed that when emodin was combined with 5-Aza-CdR, the expression levels of P16, RASSF1A and ppENK were increased more significantly compared to either treatment alone. In contrast, the expression levels of DNA methyltransferase 1 (DNMT1) and DNMT3a were more significantly reduced with the combination treatment than the control or either agent alone, further proving that emodin in combination with 5-Aza-CdR enhanced the demethylation effect of 5-Aza-CdR by reducing the expression of methyltransferases. In conclusion, the present study confirmed that emodin in combination with 5-Aza-CdR enhanced the demethylation by 5-Aza-CdR of tumor-suppressor genes p16, RASSF1A and ppENK by reducing the expression of methyltransferases DNMT1 and DNMT3a.

Effects of emodin on the demethylation of tumor-suppressor genes in pancreatic cancer PANC-1 cells.

Emodin, a natural anthraquinone derivative isolated from Rheum palmatum, has been reported to inhibit the growth of pancreatic cancer cells through different modes of action; yet, the detailed mechanism remains unclear. In the present study, we hypothesized that emodin exerts its antitumor effect by participating in the regulation of the DNA methylation level. Our research showed that emodin inhibited the growth of pancreatic cancer PANC-1 cells in a dose- and time-dependent manner. Dot-blot results showed that 40 µM emodin significantly inhibited genomic 5 mC expression in the PANC-1 cells, and mRNA-Seq showed that different concentrations of emodin could alter the gene expression profile in the PANC-1 cells. BSP confirmed that the methylation levels of P16, RASSF1A and ppENK were decreased, while concomitantly the unmethylated status was increased. RT-PCR and western blotting results confirmed that the low expression or absence of expression of mRNA and protein in the PANC-1 cells was re-expressed following treatment with emodin. In conclusion, our study for the first time suggests that emodin inhibits pancreatic cancer cell growth, which may be related to the demethylation of tumor-suppressor genes. The related mechanism may be through the inhibition of methyltransferase expression.

[Study of laser energy in multi-element detection of pulverized coal flow with laser-induced breakdown spectroscopy].

The logical range of laser power density and optimum laser power density were explored for multi-element analysis of pulverized coal flow with laser-induced breakdown spectroscopy in the present paper. The range of laser energy was chosen from 20 to 160 mJ in the experiment. Pulverized coal less than 200 microm in diameter of particles fell freely through feeder outlet and the rate of flow was controlled by screw feeder. Emissions were collected with pulse laser at 1 064 nm focusing on pulverized coal flow and plasma was generated. The intensity and cause of fluctuation of emission spectra at various laser energy levels were studied. A suitable range of laser power density is from 14.4 to 34.4 GW x cm(-2), and the optimum laser power density is 19.5 GW x cm(-2) for the determination of pulverized coal flow with LIBS.