Microbial dyes have received substantial attention because of their natural environmental protection, simple access, and reduced regional and seasonal restriction. In this work, a microbial dye, the yellow pigment produced by Metarhizium anisopliae , was first studied then applied. The strain produced by the culture was identified, and the conditions for producing yellow pigment were optimised. Further, the stability of M. anisopliae yellow pigment was examined, and the pigment was applied to the dyeing of silk and wool fabrics. The results showed that the homology of the strain with M. anisopliae was 99.98%. In liquid fermentation culture, the optimal carbon source was glucose, and the dosage was 30 g/l. The maximum pigment yield can be obtained by culturing with 4% v/v of inoculation quantity at pH 7 and 30 °C. In addition, the effects of pH, temperature and metal ions on the yellow pigment of M. anisopliae were significant. The optimum dyeing process conditions were dyeing temperatures of 80 °C for silk and 90 °C for wool, with a dyeing time of 60 min. This research developed a novel microbial dye and studied its application for the dyeing of protein fibres.
Metarhizium spp.
are widely used as
biocontrol
agents against insect pests, but the chemical basis underlying their
nematicidal activity remains largely unknown. Here, bioassay-guided
fractionation and GC–MS identified dimethyl disulfide (DMDS)
and dimethyl trisulfide (DMTS) as the major volatile nematicidal compounds
produced by Metarhizium anisopliae .
Both compounds exhibited concentration-dependent activity against
three plant-parasitic nematodes (PPNs), with 24 h LC 50 values
of 0.19–1.38 μg/mL for DMDS and 0.04–0.07 μg/mL
for DMTS. In tomato pot trials, the fermentation broth achieved 79.49%
control efficacy against Meloidogyne incognita , significantly higher than abamectin (68.24%). The GFP-labeled fungus
colonized tomato roots and persisted in the rhizosphere for 60 days.
Molecular docking and physiological assays suggested that DMDS and
DMTS disrupt calcium homeostasis, impair mitochondrial function, and
induce ROS accumulation. These findings provide new insight into the
volatile-mediated nematicidal activity of M. anisopliae and support its development as an environmentally friendly bionematicide.
The immune response of insects to pathogenic micro-organisms infection usually exhibits significant sex differences. Understanding this sexual dimorphism elucidates how immunity interplays with reproductive strategy, metabolic status and environmental factors. In this study, we showed female Drosophila melanogaster (fruit fly) survived better than males when infected with Metarhizium anisopliae CQMa421. This sex-specific survival difference depends on the Toll pathway, which is critical for innate immunity. We systematically compared innate immunity, including humoral immunity, cellular immunity, and melanization, between infected male and female flies. Female flies displayed a faster humoral immune response, characterized by earlier upregulation of antimicrobial peptides (AMPs) expression in both fat body and gut. On the other hand, male flies exhibited a stronger early cellular immune response, marked by increased expression of genes associated with hemocyte clotting and phagocytosis. While male flies upregulated melanization related Prophenoloxidase (PPO) earlier than female flies, both sexes significantly increased phenoloxidase (PO) activity after fungal infection. Fungal load quantification revealed that CQMa421 proliferated more quickly in females than in males. Collectively, our data indicate that each sex exhibits advantages in specific immune response, and that sex-biased survival outcome arises from the integration of multiple host defense mechanisms.
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