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In the current study, thirty bacterial strains isolated from the rhizosphere of Clerodendrum infortunatum L. were evaluated for the properties related to the plant growth promotion and disease resistance. Here, all the selected strains were screened for its antagonistic effect towards the phytopathogen Sclerotium rolfsii and also for the production of bioactive compounds known to promote the plant growth. Among these isolates, CiRb1 and CiRb16 were observed to have a broad range of plant beneficial features and were identified as Bacillus licheniformis and Bacillus velezensis respectively. Both the isolates were also demonstrated to produce the volatile organic compounds (VOCs) responsible for the growth enhancement in Brassica nigra (L.) and growth inhibition of S. rolfsii. Talc based formulations made out of both B. licheniformis and B. velezensis were further demonstrated to augment the plant growth and protection against S. rolfsii in Vigna unguiculata (L.) Walp. By the GC-MS based analysis, undecane could also be detected in the methanolic extracts prepared from both B. licheniformis and B. velezensis. Here, the selected rhizobacterial isolates were found to promote the plant growth and disease resistance through both direct and VOC mediated mechanisms. The results of the study hence reveal both B. licheniformis and B. velezensis have the potential in field application to promote the growth and control of plant diseases., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Clerodendrum inerme (L.) Gaertn, a halophyte, usually grows on coastal beaches as an important mangrove plant. The salt-tolerant mechanisms and related genes of this species that respond to short-term salinity stress are unknown for us. The de novo transcriptome of C. inerme roots was analyzed using next-generation sequencing technology to identify genes involved in salt tolerance and to better understand the response mechanisms of C. inerme to salt stress., Results: Illumina RNA-sequencing was performed on root samples treated with 400 mM NaCl for 0 h, 6 h, 24 h, and 72 h to investigate changes in C. inerme in response to salt stress. The de novo assembly identified 98,968 unigenes. Among these unigenes, 46,085 unigenes were annotated in the NCBI non-redundant protein sequences (NR) database, 34,756 sequences in the Swiss-Prot database and 43,113 unigenes in the evolutionary genealogy of genes: Non-supervised Orthologous Groups (eggNOG) database. 52 Gene Ontology (GO) terms and 31 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were matched to those unigenes. Most differentially expressed genes (DEGs) related to the GO terms "single-organism process", "membrane" and "catalytic activity" were significantly enriched while numerous DEGs related to the plant hormone signal transduction pathway were also significantly enriched. The detection of relative expression levels of 9 candidate DEGs by qRT-PCR were basically consistent with fold changes in RNA sequencing analysis, demonstrating that transcriptome data can accurately reflect the response of C. inerme roots to salt stress., Conclusions: This work revealed that the response of C. inerme roots to saline condition included significant alteration in response of the genes related to plant hormone signaling. Besides, our findings provide numerous salt-tolerant genes for further research to improve the salt tolerance of functional plants and will enhance research on salt-tolerant mechanisms of halophytes.

Ethnopharmacological Relevance: Clerodendrum serratum (L.) Moon. (Verbenaceae) is an important medicinal plant growing in the tropical and warm temperate regions like Africa, Southern Asia; Malaysia and distributed throughout in forests of India and Sri Lanka. It is traditionally valued and reported for treating pain, inflammation, rheumatism, respiratory disorders, fever and malarial fever in India with a long history. To provide a comprehensive overview of the traditional and ethno medicinal uses, phytochemistry and biological activities of C. serratum with clinical and toxicity data and possibly make recommendations for further research., Materials and Methods: All relevant worldwide accepted databases were searched for the terms "Clerodendrum", "Clerodendrum serratum", "Bharangi" and "Cheruthekku" along with the other literature from Indian classical texts and pharmacopoeias. There was no specific timeline set for the search. The accessible literatures available on C. serratum were collected via electronic search using Pubmed, Scopus, Science Direct and traditional books reports on ethnopharmacology and traditional medicines., Results: C. serratum has played an important role in Indian system of medicine. In addition to the common local use in respiratory diseases, other ethnomedicinal uses include treatment of pain, inflammation, rheumatism and fever especially malarial fever. Scientific studies on extracts and formulations revealed anti-asthmatic, mast cell stabilization and anti-allergic effects of roots of C. serratum. Reported data on pharmacological activities also includes hepatoprotective, anti-oxidant, anti-inflammatory and anticancer potential of the drug. Saponins (terpenoids and steroids), flavonoids and phenolics isolated from roots have been the focus of phytochemical investigations as the biological activity has been ascribed to the saponins, which are known to possess anti-inflammatory and anti-cancer activity. Isolated bioactives from roots like icosahydropicenic acid and ursolic acid have been claimed to offer anti-allergic and hepatoprotective activity., Conclusions: Therapeutic potential of roots and leaves of C. serratum has been demonstrated in the conditions like asthma, allergy, fever, inflammation and liver disorders attributed to the presence of various flavonoids, phenolics and saponins present in the drug. Many ethnobotanical claims have been confirmed through modern in-vitro and in-vivo pharmacological studies of different extracts and isolates from plant; however, additional studies on the biomarkers are needed to establish mechanism of action and to validate the traditional use of this drug in clinical practices after proper safety assessment., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Rapid micropropagation through adventitious shoot induction from in vitro raised leaf explants of Clerodendrum aculeatum (Verbenaceae), was successfully achieved for the first time. Basal portion of the leaves showed highest regeneration potential when grown on MS medium supplemented with BA (5.0 mg/l) and NAA and IBA (0.5 mg/l of each). Shoots after elongation in growth regulator-free medium, were rooted in MS medium containing 0.5 mg/l of NAA and IBA. Aqueous leaf extract of in vitro raised plants, induced high degree of resistance against viruses in susceptible healthy hosts when applied prior to virus inoculation. Upon purification from leaves of cultured plants, the resistance inducing protein, showed molecular mass of 34 kDa. Amount of resistance inducing protein obtained from leaves of cultured plants, was consistent throughout the year, as compared to the protein isolated from leaves of field grown plants, which showed marked seasonal fluctuation. The purified 34 kDa protein from in vitro raised plants, was serologically related to field grown plants and possessed similar characteristics. The micropropagated plants were successfully established in earthen pots under greenhouse conditions.