The crown rot of wheat is a destructive soil-borne pathogen that severely reduces the yield and quality of wheat. This study aimed to screen and identify the antagonistic strains against Fusarium pseudograminearum (Fp), which is the dominant pathogen associated with the crown rot of wheat in China, and evaluate their biosynthetic potential. The antagonistic strains were screened via a dual-culture antagonism assay, and then identified by combining the morphological characteristics and internal transcribed spacer gene sequencing. The polyketide synthases (PKS-I and PKS-II) and non-ribosomal peptide synthetase (NRPS) genes in the antagonistic strains were detected via specific amplification of chromosomal DNA. Eleven out of 157 fungal strains, including six strains with matrix competition and five strains with antibiosis, were obtained. The eleven antagonistic strains belonged to the following four genera: Alternaria, Botryosphaeria, Phoma and Talaromyces. The inhibition rate of six strains with matrix competition was greater than 50%, with B. dothidea S2-22 demonstrating the highest at 80.3%. The width of the inhibition zone of T. trachyspermus R-17 among the five strains with antibiosis was the widest at 11 mm. Among the eleven antagonistic strains, three strains of A. alternata and the strain P. moricola only contained the PKS-II gene, the strain A. tenuissima contained PKS-I and PKS-II genes, three strains of B. dothidea contained PKS-II and NRPS genes, while three strains of T. trachyspermus did not contain any genes. These results demonstrated potential strains for the biocontrol of the crown rot of wheat. In particular, T. trachyspermus R-17 can be investigated further as a promising agent, and the active substances secreted by antagonistic strains may be synthesized by other pathways.

Prunella vulgaris, an essential component of traditional Chinese medicine, is suitable for growing in soil with a pH value ranging from 6.5 to 7.5. However, it is primarily cultivated in acidic soil regions of China, where its growth is frequently compromised by acidic stress. Selenium (Se) has been recognized for its potential to enhance stress tolerance in plants. However, its role in acid-stress-induced oxidative stress is not clear. In this study, the effects of varying Se concentrations on the growth and quality of P. vulgaris under acidic stress were investigated. The results showed that acid stress enhanced antioxidant enzyme activities, non-enzymatic antioxidant substances, and osmolyte content, accompanied by an increase in oxidant production and membrane damage. Furthermore, it decreased the photosynthetic capacity, inhibited root and shoot growth, and diminished the yield of P. vulgaris. In contrast, exogenous application of Se, particularly at 5 mg L⁻¹, markedly ameliorated these adverse effects. Compared to acid-stressed plants, 5 mg L⁻¹ Se treatment enhanced superoxide dismutase, peroxidase, ascorbate peroxidase, and glutathione peroxidase activities by 150.19%, 54.94%, 43.43%, and 45.55%, respectively. Additionally, soluble protein, soluble sugar, and proline contents increased by 11.75%, 23.32%, and 40.39%, respectively. Se application also improved root architecture and alleviated membrane damage by reducing hydrogen peroxide, superoxide anion, malondialdehyde, and electrolyte leakage levels. Furthermore, it significantly enhanced the photosynthetic capacity by elevating pigment levels, the performance of PSI and PSII, electron transfer, and the coordination of PSI and PSII. Consequently, plant growth and spica weight were significantly promoted, with a 12.50% increase in yield. Moreover, Se application upregulated key genes involved in flavonoid and phenolic acid metabolic pathways, leading to elevated levels of total flavonoids, caffeic acid, ferulic acid, rosmarinic acid, and hyperoside by 31.03%, 22.37%, 40.78%, 15.11%, and 20.84%, respectively, compared to acid-stressed plants. In conclusion, exogenous Se effectively alleviated the adverse effects of acid stress by improving the antioxidant system, growth, and photosynthetic capacity under acid stress, thus enhancing the yield and quality of P. vulgaris.

In this study, a UDP-glycosyltransferase gene from Forsythia suspensa was systematically identified and functionally characterized. Phylogenetic analysis showed that this gene clustered with members of the UGT74 subfamily, where it clustered closely with members of known function; accordingly, it was provisionally designated as FsUGT74F1. Prokaryotic expression experiments determined that soluble recombinant protein could be obtained under induction conditions of 0.1 mM IPTG at 16 °C for 8 h. In vitro enzyme activity assays suggested that FsUGT74F1 might catalyze the glycosylation of phillygenin using UDP-glucose under the tested conditions, yielding a product whose HPLC retention time was consistent with that of authentic phillyrin. Subcellular localization results indicated that FsUGT74F1 was predominantly associated with the plasma membrane. Transient overexpression of FsUGT74F1 in F. suspensa leaves resulted in upregulation of gene expression by approximately 247.6%, and the phillyrin content increased to 124.7% of that in the control group. Conversely, virus-induced gene silencing (VIGS) of FsUGT74F1 led to a reduction in transcript levels by approximately 35.6%, and the phillyrin content decreased to 72.5% of the control level. Molecular docking suggested that phillygenin could interact with FsUGT74F1, with Leu169 predicted to participate in substrate positioning near the C4′-OH group. Collectively, these results support the involvement of FsUGT74F1 in phillyrin biosynthesis and provide a theoretical basis for its application in metabolic engineering.

Background: Forsythia suspensa (Thunb.) Vahl is a perennial deciduous shrub of the Oleaceae family. Its dried mature fruits are used as medicine and hold an important position in traditional Chinese medicine. Tyrosine decarboxylase (TyDC) is a key enzyme involved in the synthesis of dopamine in Forsythia suspensa. At the same time, it also affects the growth and development of this species under biotic stress. Methods: This study examined the expression and function of FsTyDC1 under drought and salt stress. The TyDC gene identified in F. suspensa, termed FsTyDC1, has an open reading frame (ORF) of 1518 bp. Results: qRT-PCR and subcellular localization analyses indicated that FsTyDC1 is highly expressed in F. suspensa fruit and its protein is located in the cytoplasm. The gene was silenced using a pTRV2-FsPDS/FsTyDC1 vector with virus-induced gene silencing. Following exposure to drought and salt stress, the leaves of FsTyDC1-silenced plants exhibited increased curling and wilting. Conclusions: The results indicate that FsTyDC1 responds to both salt and drought stress, which provides a foundation for further investigation into the function of FsTyDC1.