Indole-3-acetic acid (IAA) belongs to the family of auxin indole derivatives. IAA regulates almost all aspects of plant growth and development, and is one of the most important plant hormones. In microorganisms too, IAA plays an important role in growth, development, and even plant interaction. Therefore, mechanism studies on the biosynthesis and functions of IAA in microorganisms can promote the production and utilization of IAA in agriculture. This mini-review mainly summarizes the biosynthesis pathways that have been reported in microorganisms, including the indole-3-acetamide pathway, indole-3-pyruvate pathway, tryptamine pathway, indole-3-acetonitrile pathway, tryptophan side chain oxidase pathway, and non-tryptophan dependent pathway. Some pathways interact with each other through common key genes to constitute a network of IAA biosynthesis. In addition, functional studies of IAA in microorganisms, divided into three categories, have also been summarized: the effects on microorganisms, the virulence on plants, and the beneficial impacts on plants.

The primary functions of mitochondria are to produce energy and participate in the apoptosis of cells, with them being highly conserved among eukaryotes. However, the composition of mitochondrial genomes, mitochondrial DNA (mtDNA) replication, and mitochondrial inheritance varies significantly among animals, plants, and fungi. Especially in fungi, there exists a rich diversity of mitochondrial genomes, as well as various replication and inheritance mechanisms. Therefore, a comprehensive understanding of fungal mitochondria is crucial for unraveling the evolutionary history of mitochondria in eukaryotes. In this review, we have organized existing reports to systematically describe and summarize the composition of yeast-like fungal mitochondrial genomes from three perspectives: mitochondrial genome structure, encoded genes, and mobile elements. We have also provided a systematic overview of the mechanisms in mtDNA replication and mitochondrial inheritance during bisexual mating. Additionally, we have discussed and proposed open questions that require further investigation for clarification.

Manuka honey (MH) is increasingly recognized for its potent antioxidant properties, making it a promising functional food ingredient. However, discrepancies in assessment methods have impeded the standardization of its antioxidant capacity. This study compared DPPH, ABTS, and cellular antioxidant activity (CAA) assays under varying conditions to identify the most reliable approach for assessing MH’s antioxidant properties. The results showed that the reaction temperature for the chemical method, setting it at 37 °C, enhanced the antioxidant capacity of MH. For the cellular assay, we optimized honey concentration, injury duration, damage model, and cell model. The result showed that sugar-reduced MH achieved the same high efficiency as the chemical method. A stable cellular assay method was established in HepG2 cells, offering superior reproducibility with an intra-RSD of 4.83% (<5%) and an inter-RSD of 7.51% (<10%). Additionally, studies have found that methyl syringate (MSY), a key polyphenolic compound in Manuka honey (MH), exhibits extremely high antioxidant activity. However, due to its low concentration, its overall contribution to the honey’s antioxidant activity is limited. This optimized CAA-based approach provides reliable technical support for the accurate evaluation of the antioxidant activity of MH.

Ustilago esculenta is a fungus of two morphological forms, among the filamentous dikaryon that can induce the plant stem to expand to form fleshy stem. In order to establish biotrophy with Zizania latifolia which belongs to the tribe Oryzeae (Poaceae), U. esculenta firstly needs to secrete a bunch of effectors, among them being cell wall degrading enzymes (CWDEs). We have isolated a gene, UeEgl1, which was differentially expressed in MT-type and T-type U. esculenta at an early stage of infection, and specifically induced in the filamentous growth of the T-type. Bioinformatics analysis and enzyme activity assay indicated that UeEgl1 functions outside the cell as a β-1,4-endoglucanase with a conserved domain of the glycosyl hydrolase family 45 (GH45) which targets the main component of the plant cell wall β-1,4 linked glycosidic bonds. The phenotype analysis of UeEgl1 deletion mutants and UeEgl1 over-expression transformants showed that UeEgl1 had no significant effect on the budding, cell fusion, and filamentous growth of U. esculenta in vitro. Further study found that over-expression of UeEgl1 promoted the proliferation of mycelia inside Z. latifolia, and raised plant defense responses. The above results show that the UeEgl1 gene may play an important role in the early stage of infection through the decomposition of the plant cell wall.

Inflammatory responses and tumor developments are closely related, with interleukin-6 (IL-6) playing important roles in both processes. IL-6 has been extensively identified as a potential tumor biomarker. This study developed an isotope dilution mass spectrometry (IDMS) method for quantifying IL-6 based on signature peptides. These peptides were screened by excluding those with missed cleavage or post-translational modification. The method’s accuracy was verified using amino acid-based IDMS, in which purified IL-6 protein samples were quantified after hydrolyzing them into amino acids, and no significant difference was observed (p-value < 0.05). The method demonstrated good linearity and sensitivity upon testing. The specificity and matrix effect of the method were verified, and a precision study showed that the coefficient of variation was less than 5% for both the intra-day and inter-day tests. Compared to immunoassays, this method offers distinct advantages, such as the facilitation of multi-target analysis. Furthermore, the peptides used in this study are much more convenient for storage and operation than the antibodies or purified proteins typically used in immunoassays.

Citrus alternaria brown spot, caused by the tangerine pathotype of Alternaria alternata, is one of the most severe fungal diseases affecting citrus crops. Currently, there is a critical need for rapid and visual detection techniques to identify the tangerine pathotype of A. alternata. In this study, a novel detection system was developed by combining recombinase polymerase amplification (RPA) with CRISPR/Cas12a technology, targeting the ACTT3 gene specific to the tangerine pathotype of A. alternata. Through optimization of reaction time and component concentrations, the assay demonstrated a detection sensitivity of 1 pg μL⁻¹ within 40 min at a constant temperature of 37 °C. The results can be visually interpreted using nucleic acid test strips, offering advantages in specificity, sensitivity, and speed. This system has been successfully validated for the rapid detection of the pathogen within plant tissues, including leaves and fruits, providing an efficient and practical solution for real-time field detection of the tangerine pathotype of A. alternata.