Search Results (2)

p-coumaric acid (p-CA) is one of the main allelochemicals of cultivable Morchella mushrooms. However, its toxicity mechanism has not been elucidated. Therefore, we used physiological and comparative transcriptomic analyses to reveal its toxicity mechanism. The results suggest that the mycelial growth and sclerotial production of M. importuna were promoted under treatment with a low dosage of p-CA (10 μg/mL). The treatment induced moderate reactive oxygen species (ROS) accumulation, with an upregulation of genes associated with antioxidant regulation, energy supply and damage repair. In contrast, oxidative stress induced under treatment with a high dosage of p-CA (50 μg/mL) led to strain ageing. The contents of ROS were significantly increased, along with decreased peroxidase and catalase activity. Moreover, the genes associated with H₂O₂ synthesis were upregulated, while those responsible for H₂O₂ decomposition, non-enzymatic antioxidant components and damage repair were downregulated. Meanwhile, the carbohydrate and lipid metabolic pathways, and the signal transduction and cell division pathways, were impaired. Taken together, moderate stress induced under a low concentration of p-CA promotes the mycelial growth and sclerotial metamorphosis of M. importuna. This study provides new insights into the potential mechanisms of continuous cropping obstacles in the cultivation of morel mushrooms, which is of great importance for the practical aspects of mushroom cultivation. Full article

The coastal Casuarina equisetifolia is the most common tree species in Hainan’s coastal protection forests. Sequencing the genomes of its allelopathic endophytes can allow the protective effects of these bacteria to be effectively implemented in protected forests. The goal of this study was to sequence the whole genomes of the endophytes Bacillus amyloliquefaciens and Bacillus aryabhattai isolated from C. equisetifolia root tissues. The results showed that the genome sizes of B. amyloliquefaciens and B. aryabhattai were 3.854 Mb and 5.508 Mb, respectively. The two strains shared 2514 common gene families while having 1055 and 2406 distinct gene families, respectively. The two strains had 283 and 298 allelochemical synthesis-associated genes, respectively, 255 of which were shared by both strains and 28 and 43 of which were unique to each strain, respectively. The genes were putatively involved in 11 functional pathways, including secondary metabolite biosynthesis, terpene carbon skeleton biosynthesis, biosynthesis of ubiquinone and other terpene quinones, tropane/piperidine and piperidine alkaloids biosynthesis, and phenylpropanoid biosynthesis. NQO1 and entC are known to be involved in the biosynthesis of ubiquinone and other terpenoid quinones, and rfbC/rmlC, rfbA/rmlA/rffH, and rfbB/rmlB/rffG are involved in the biosynthesis of polyketide glycan units. Among the B. aryabhattai-specific allelochemical synthesis-related genes, STE24 is involved in terpene carbon skeleton production, atzF and gdhA in arginine biosynthesis, and TYR in isoquinoline alkaloid biosynthesis. B. amyloliquefaciens and B. aryabhattai share the genes aspB, yhdR, trpA, trpB, and GGPS, which are known to be involved in the synthesis of carotenoids, indole, momilactones, and other allelochemicals. Additionally, these bacteria are involved in allelochemical synthesis via routes such as polyketide sugar unit biosynthesis and isoquinoline alkaloid biosynthesis. This study sheds light on the genetic basis of allelopathy in Bacillus strains associated with C. equisetifolia, highlighting the possible use of these bacteria in sustainable agricultural strategies for weed management and crop protection. Full article