Improvement of Phytopharmaceutical and Alkaloid Production in Periwinkle Plants by Endophyte and Abiotic Elicitors

Abstract

Periwinkle plant represents a major source of immensely vital terpenoid indole alkaloids and natural antioxidants which are widely used in cancer chemotherapy. A pot experiment was done to evaluate the role of two periwinkle endophytes (Streptomyces sp. and Bacillus sp.) with or without abiotic elicitors (aluminum chloride, tryptophan, and chitosan) on plant biomass, physio-biochemical attributes, phytopharmaceutical constituents, and alkaloid production. Inoculation with endophyte microbes significantly increased plant growth, nitrogen, phosphorus, potassium, carotenoids, ascorbic acid, and alkaloid yield. It also decreased oxidative biomarkers (hydrogen peroxide and malondialdehyde) and had no significant effects on flavonoids and anthocyanin. In this regard, Streptomyces sp. was more effective than Bacillus sp. Foliar spraying with chitosan significantly increased plant growth, chlorophyll, ions, antioxidant capacity, phytopharmaceutical constituents (total soluble phenols, flavonoids, and anthocyanin), and alkaloid yield, associated with a decline in oxidative biomarkers. Conversely, aluminum chloride application generally increased oxidative biomarkers, which was associated with a decreasing effect on plant growth, chlorophyll, and ions. Application of either tryptophan or chitosan with endophyte microbes increased plant growth, chlorophyll, ions, antioxidants, and alkaloid; meanwhile, it decreased oxidative biomarkers. On the contrary, aluminum chloride with endophytes evoked oxidative damage that was associated with a reduction in plant growth, chlorophyll, ions, and phytopharmaceutical constituents. The current study provides a proof-of-concept of the use of the endophyte Streptomyces sp. with chitosan for enhancing periwinkle plant biomass, phytopharmaceuticals accumulation, and alkaloid production.

Soil Application of Bacillus subtilis Regulates Flavonoid and Alkaloids Biosynthesis in Mulberry Leaves

“…In this study, application BS agents resulted in a decrease in the synthesis of flavonoids, as well as an increase in the synthesis of DNJ in mulberry leaves. This is consistent with previous studies showing that inoculation with PGPR has the potential to increase alkaloid yield in plants [35,36] but inconsistent with the results stating that B. subtilis-treated plants exhibited significantly improved synthesis of flavonoids [26,37,38].…”

Novel Approaches for Sustainable Horticultural Crop Production: Advances and Prospects

“…It is widely reported that endophyte-mediated plant growth improvement occurs through biofertilization and biostimulation: (i) providing the hosts with water and essential nutrients, such as N and P, by transforming them into effortless types, being digestible (using N fixatives, P solubilizers, siderophore producers, etc.) [19][20][21]91]; (ii) the synthesis of growth phytohormones (auxins (IAA), cytokinins (CKs), and gibberellins (GBs)) or alter the synthesis of stress and signaling phytohormones (i.e., abscisic acid (ABA), salicylic acid (SA), ethylene, and jasmonates) [19,21,23,[92][93][94]; and (iii) the synthesis of many compounds with protective and signaling functions (i.e., antibiotics, enzymes, siderophores, LPs, hydrogen cyanide and others) [30,31,82,90,94,95] (Figure 2). Endophytes are capable of dissolving water-insoluble and other inaccessible forms of P, K, Mg and other essential compounds through the production of organic and inorganic acids, protons, hydroxyl ions and CO2 that facilitate their uptake by plants [96][97][98][99][100].…”

“…Nowadays, the ubiquity of endophytic microorganisms is widely recognized and the opportunities for their use in crop production are of great interest [14][15][16][17]. The physiological action of beneficial microbial endophytes on host plants is associated with effective competition for space and nutrients with phytopathogens [18], improving the bioavailability of macro-/microelements and the mineral nutrition of plants [19][20][21], photosynthesis [22,23], stomatal conductance [24], water status [25], modulating the endogenous hormonal background influencing the architecture of the root system [26,27], regulating the production of phytohormones and their accumulation in plants [14,26,27], activating the synthesis of various antioxidant and osmoprotective compounds [28,29], various biologically active substances [19,[29][30][31] and signaling molecules that activate induced systemic defense in hosts against biotic [32][33][34] and abiotic stresses [35,36]; thereby leading to better plant growth, yield and product quality.…”