Understanding Camellia sinensis using Omics Technologies along with Endophytic Bacteria and Environmental Roles on Metabolism: A Review

Abstract

Camellia sinensis is the most consumed beverage worldwide. It contains a wide variety of secondary metabolites, such as alkaloids, saponins, tannins, catechins, and polyphenols, generated through a condensation reaction of cinnamic acid with three malonyl-CoA groups. In addition to the metabolic processes occurring within this plant, there are also some plant-associated bacterial endophytes. These bacteria reside in the living tissues of the host plants without causing any harmful effect to them, thereby stimulating secondary metabolite production with a diverse range of biological effects. Omics technologies reveal understanding of the biological phenomena of transcriptomics, proteomics, and metabolomics. In this sense, the present review aims to provide a comprehensive review of various methods used to identify distinct plant compounds, namely transcriptomic, proteomic, and metabolomic analysis. The role of endophytic bacteria in C. sinensis metabolism, and C. sinensis antioxidant and antimicrobial effects, are also carefully highlighted.

Bacterial endophytes: Molecular interactions with their hosts

“…The identification of particular genes involved in N-acyl homoserine lactone synthases and hydrolases, hyperadherence factors, fusaric acid resistance proteins, and so forth, and mechanism of antibiotic resistance, antibiotic production, plant growth promotion, endophytic secretory system, surface attachment and insertion elements, transport system, and other related metabolic mechanisms is of immense importance. Although a large number of methodologies are available, but actual utilization of these for the study of different host plant and endophytic genes involved in plant-microbe and microbe-microbe interactions is very cumbersome and possibility and feasibility are also very low [40][41][42][43]. However, despite the difficulties, these methods have been used successfully to understand the genetics of these interactions.…”

“…Kp13 encoded 12 copies of genes for siderophore receptors including five TonB-dependent outer membrane receptors, three putative ferric enterobactin receptors (fepA), a catecholate siderophore receptor (fiu), a ferric aerobactin receptor, a ferrioxamine receptor (foxA), a ferrichrome outer membrane receptor, and the ferric uptake regulator (fur). In addition, 43 ORFs that encode iron transport corresponding to the ferrous iron transporters involved in Fe 2+ capture and also the sitABCD system responsible for the transport of bivalent cations like Mn 2+ and Fe 2+ were also present within the genome [121].…”

Plant-microbe Interactions for Sustainable Agriculture in the Postgenomic Era

“…In recent years, various high-throughput ‘omics’ approaches have advanced biological science; these approaches include genomics, the study of the structural and functional aspects of genes; and comparison of the degree of gene expression in contrasting genotypes, transcriptomics that quantifies mRNA transcripts, proteomics that analyzes the protein composition and metabolomics which identifies and quantifies cellular metabolites [ 30 - 32 ]. ‘Omics’ platforms are widely used in understanding and selecting efficient endophytic or beneficial strains with various improved traits such as nutrient uptake, imparting abiotic and biotic stress tolerance during their interaction with plants [ 33 , 34 ]. Comparative studies by large-scale genome and proteome analysis of hosts and pathogens have helped in the identification of various effector genes, key proteins and the nature of pathogenesis induced by pathogen and also the difference in defense mechanisms elicited by the plants [ 35 , 36 ].…”

Establishment and Functionality of Diverse Endophytic Bacteria from Different Hosts in Chickpea and Wheat Microbiome

“…identified by Ali et al, (2014a, b) by comparing the complete genomes of different Proteobacterial endophytes. The mechanisms employed by bacteria to promote plant growth are now better understood (Gamalero and Glick, 2011;Glick, 2012;Tshikhudo et al, 2019). PGPB and particularly endophytic bacteria promote the growth of plants by possessing multiple beneficial traits like production of phytohormones, auxins, IAA, Gibberellin, together with cytokinin and ethylene (Dudeja 2012;Etesami and Maheshwari 2018).…”

“…However both types act as plant growth promoting bacteria (PGPB); rhizospheric bacteria, that are typically found around the roots of plants; and endophytic bacteria that are found within the various tissues of the plant itself (e.g. roots, nodules, stems, leaves, seeds, and fruits) (Ryan et al, 2008;Lacava and Azevedo, 2013;Tshikhudo et al, 2019).…”