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Many plants possess immense pharmacological properties because of the presence of various therapeutic bioactive secondary metabolites that are of great importance in many pharmaceutical industries. Therefore, to strike a balance between meeting industry demands and conserving natural habitats, medicinal plants are being cultivated on a large scale. However, to enhance the yield and simultaneously manage the various pest infestations, agrochemicals are being routinely used that have a detrimental impact on the whole ecosystem, ranging from biodiversity loss to water pollution, soil degradation, nutrient imbalance and enormous health hazards to both consumers and agricultural workers. To address the challenges, biological eco-friendly alternatives are being looked upon with high hopes where endophytes pitch in as key players due to their tight association with the host plants. The intricate interplay between plants and endophytic microorganisms has emerged as a captivating subject of scientific investigation, with profound implications for the sustainable biosynthesis of pharmaceutically important secondary metabolites. This review delves into the hidden world of the "secret wedlock" between plants and endophytes, elucidating their multifaceted interactions that underpin the synthesis of bioactive compounds with medicinal significance in their plant hosts. Here, we briefly review endophytic diversity association with medicinal plants and highlight the potential role of core endomicrobiome. We also propose that successful implementation of in situ microbiome manipulation through high-end techniques can pave the way towards a more sustainable and pharmaceutically enriched future., (© 2023. The Author(s).)

Bacopa monnieri is the main source of pharmaceutically important bacosides; however, the low content of these molecules in planta remains a limiting factor for fulfilling the industrial requirement. The accumulation of secondary metabolites can be enhanced in plants upon inoculation with endophytes. In this study, we isolated and analyzed the culturable endophytes associated with different plant parts. By analyzing their impact on plant growth parameters (in vitro and in vivo) and Bacoside A content, we found few candidates which increased bacoside accumulation significantly. Finally, two promising endophytes namely Bacillus subtilis (OK070745) and Klebsiella aerogenes (OK070774) were co-cultivated with B. monnieri cuttings singly and in combination mode to clarify their effect on bacoside biosynthesis and their accumulation in B. monnieri shoot. Consortium-inoculated plants significantly enhanced the plant biomass and Bacoside A content with respect to single inoculation. The results of real-time quantitative (RT-PCR) revealed significant accumulation of bacoside biosynthetic pathway transcripts (HMGCR, PMVK, FDPS, SQS, and b-AS) in the case of plants inoculated with microbial combination, while the single inoculation of B. subtilis diverted the plant's machinery toward the synthesis of phenylpropanoid genes like CCR, CAD, CHS, and HST. In addition, higher expression of MYB 2 and WRKY 1 transcription factors in combinational treatment points out their probable role in better physiological and developmental processes. Altogether, this is the first study on B. monnieri-endophyte interaction showing improvement in the accumulation of bacoside A by modulating various genes of metabolic pathway and thus suggests an effective "green approach" for augmenting in planta production of pharmaceutically important bacosides. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Plants and endophytes interaction: a 'secret wedlock' for sustainable biosynthesis of pharmaceutically important secondary metabolites" published in the journal Microbial Cell Factories. The correction addresses an error in the affiliation details of the corresponding author, Vaibhav Srivastava. The corrected affiliation should be "Division of Glycoscience, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology, and Health, KTH Royal Institute of Technology, AlbaNova University Center, 106 91 Stockholm, Sweden." The original article has been corrected. The publisher, Springer Nature, remains neutral regarding jurisdictional claims and institutional affiliations. [Extracted from the article]

A wheat endophytic bacterium ( Pseudomonas aeruginosa PW09) was evaluated for its ability to trigger an induced systemic resistance response in cucumber against biotic and abiotic stresses. PW09 was applied to cucumber seeds, and the seedlings were subjected to Sclerotium rolfsii infection and NaCl (150 m m). The role of PW09 was evaluated in alleviating the stresses by assessing plant mortality due to S. rolfsii infection and biomass accumulation under NaCl stress as well as at the physiological level through phenylpropanoid metabolism, antioxidant activities and proline accumulation. The endophyte reduced seedling mortality by 60% and increased biomass accumulation significantly under S. rolfsii (7%) and NaCl (18%) stresses, respectively, compared with endophyte-untreated seedlings. Application of PW09 also induced higher accumulation of proline (1.3- and 1.4-fold) and total phenolics (1.2- and 1.1-fold) and activities of polyphenol oxidase (4.3- and 1.5-fold), phenylalanine ammonia lyase (1.29- and 1.27-fold) and superoxide dismutase (2.5- and 1.39-fold) under S. rolfsii and NaCl stresses, indicating the ability of the wheat endophyte PW09 in alleviating both biotic and abiotic stresses in cucumber. [ABSTRACT FROM AUTHOR]

The rich diversity of microbial endophytic communities associated with plants, often referred to as the second genome, serves as a compelling illustration of efficient co-evolution. This noteworthy partnership plays a pivotal role in sustaining plant well-being and enhancing plant adaptability across diverse habitats. Therefore, examining the diversity of endophytic microbes associated with their particular host plant is valuable for gaining insights into the vast spectrum of plant-microbe interactions. The present experiments aimed at investigating the bacterial endophytic diversity in both root and shoot tissues of Pelargonium graveolens , employing culture dependent and culture independent high-throughput metagenomics approach. A total of 614 and 620 operational taxonomic units (OTUs), encompassing 291 and 229 genera, were identified in the shoot and root tissues of P. graveolens , respectively. Furthermore, the subsequent classification of OTUs revealed 15 highly abundant phyla, with Proteobacteria dominating both root and shoot tissues. Notably, an exceptionally high abundance of Firmicutes phyla was observed in the shoot compared to the root. Additionally, 30 bacterial endophytes from the root, stem, petiole, and leaves were isolated and molecularly characterized, unveiling a consistent pattern of diversity distribution between the root and shoot of P. graveolens. Upon screening all isolates for plant growth promoting traits, Pseudomonas oryzihabitans was found to be positive for major biochemical test like nitrogen fixation, phosphate solubilization etc. and on inoculation resulted in about two-fold increase in content of essential oil accompanied by a significant rise in the geraniol and citronellol content. Diving deep into the genetic constitution of P. oryzihabitans unveiled a substantial number of genes directly and indirectly contributing to the endophyte's capability in colonizing host plants effectively. In summary, data obtained from metagenomics and culture dependent approaches including glass house trials suggest potential bacterial endophytes suitable for field applications for yield enhancement and in planta secondary metabolite enhancement investigations. [Display omitted] [ABSTRACT FROM AUTHOR]

Andrographis paniculata is a common medicinal plant used worldwide for its preventive and curative properties. However, no information exists about the A. paniculata associated bacterial endophytes and their potential relationship with the plant-bioactive substances. In this study, we investigated the bacterial endophytic diversity of A. paniculata root and shoot tissues using culture-based and culture-independent high-throughput sequencing methods. The culture-independent analyses unveiled the presence of 465 operational taxonomic units (OTU's) and 232 genera, respectively in the samples. Further, downstream categorization of OTU's revealed the dominance of Proteobacteria, Firmicutes, Actinobacteria and Bacteriodetes phylum members, with Bacillus being the most prevalent endophytic genera in the root, while Pseudomonas dominated the shoot tissues. A total of 39 bacterial endophytes from the roots, stems, leaves, and seeds of A. paniculata were isolated by a culture-dependent investigation whose subsequent examination using 16S rRNA gene sequencing confirmed a similar pattern of the dominance of the Bacillus and Pseudomonas genera. When all the isolates were further screened for their plant growth promotion activity, Micrococcus luteus (ASd6) significantly enhanced the biomass and andrographolide content by 68.01% and 44.16%, respectively. Taken together, the information captured through metagenomics and culture-dependent approach reveals some promising bacterial endophytes which could be employed in field for growth promotion and in planta secondary metabolite enhancement studies in near future. [Display omitted] • Bacterial endomicrobiome diversity was influenced by plant tissue type in A. paniculata. • Proteobacteria, Firmicutes, Actinobacteria and Bacteriodetes are the dominant phylum of A. paniculata. • The shoot has more endophytic bacterial diversity in comparison to the roots of A. paniculta. • Bacillus is the most prevalent genus in the root, while Pseudomonas dominated the shoot tissue. • Micrococcus luteus significantly enhanced the biomass and andrographolide content [ABSTRACT FROM AUTHOR]