Seed germination-influencing bioactive secondary metabolites secreted by the endophyte Cladosporium cladosporioides LWL5

Improved seed germination and plant growth mediated by compounds synthesized by endophytic Aspergillus niger (isolate 29) isolated from Albizia lebbeck (L.) Benth

Plant-microbe interactions are remarkably diverse and dynamic. These interactions can be in the form of endophytic association. Colonization of endophytic microflora in crop plants improves crop health leading to crop enhancement. They stimulate the overall growth of plants by facilitating nutrient uptake and regulating various hormones. This eventually improves the plant biomass and grain yield. Owing to the assistance of the endophytes to the host plants, augmentation of crop plants with potential fungal endophytes or their extracted bioactive compound can upsurge the overall crop production and provide promising solutions for environmentally sustainable agriculture. In this light, the present study deals with the prospects of bioactive metabolites produced by endophytic fungi in Albizia lebbeck (L.) Benth, a medicinal native plant of Rajasthan. The metabolomic analysis of a partially purified extract of Aspergillus niger (isolate 29) showed the presence of a total of 919 compounds using UHPLC-MS/MS. The metabolic pathway analysis revealed that these compounds were influencing super pathway of gibberellin and isoflavonoid biosynthesis. Significant increase in seed germination percentage (73-93%), seed vigour index (834.44-1498.21) and germination index (2.54-3.67 seeds/day) was found in treated seeds compared to untreated. There was a significant improvement in root (45-185%) and shoot length (215-295%) of wheat, barley and millet and a significant increase in root number (38-97%) in wheat and barley. Positive correlation was observed in the growth parameters of all the crops upon treatment. Overall, the results indicated that the partially purified fraction of A. niger (isolate 29) improved seed germination and promoted plant growth in cash crops. The results emphasize towards the importance of secondary metabolites in seed germination and enhancement of plant growth. These results also suggest a probable mutualistic role of endophyte with the host plant.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-022-03332-x.

The Genus Cladosporium: A Rich Source of Diverse and Bioactive Natural Compounds

Fungi are renowned as one of the most fruitful sources of chemodiversity and for their ubiquitous occurrence. Among the many taxonomic groupings considered for the implications deriving from their biosynthetic aptitudes, the genus Cladosporium stands out as one of the most common in indoor environments. A better understanding of the impact of these fungi on human health and activities is clearly based on the improvement of our knowledge of the structural aspects and biological properties of their secondary metabolites, which are reviewed in the present paper.

Controlling weeds with fungi, bacteria and viruses: a review

Weeds are a nuisance in a variety of land uses. The increasing prevalence of both herbicide resistant weeds and bans on cosmetic pesticide use has created a strong impetus to develop novel strategies for controlling weeds. The application of bacteria, fungi and viruses to achieving this goal has received increasingly great attention over the last three decades. Proposed benefits to this strategy include reduced environmental impact, increased target specificity, reduced development costs compared to conventional herbicides and the identification of novel herbicidal mechanisms. This review focuses on examples from North America. Among fungi, the prominent genera to receive attention as bioherbicide candidates include Colletotrichum, Phoma, and Sclerotinia. Among bacteria, Xanthomonas and Pseudomonas share this distinction. The available reports on the application of viruses to controlling weeds are also reviewed. Focus is given to the phytotoxic mechanisms associated with bioherbicide candidates. Achieving consistent suppression of weeds in field conditions is a common challenge to this control strategy, as the efficacy of a bioherbicide candidate is generally more sensitive to environmental variation than a conventional herbicide. Common themes and lessons emerging from the available literature in regard to this challenge are presented. Additionally, future directions for this crop protection strategy are suggested.