Plant-endophyte mediated improvement in physiological and bio-protective abilities of marigold (Tagetes patula)

Abstract

Endophytic bacteria improve the growth, physiology, and metabolite profile of plants. They are known as potential biocontrol agents of soil-borne diseases. This study evaluated the effects of endophytic bacterial strains on growth, vase life, biochemical attributes, and antioxidant and nematicidal activities of French marigold (Tagetes patula). French marigold seeds were sole and consortium inoculated with three promising endophytic bacterial strains, Burkholderia phytofirmans (PsJN), Enterobacter sp. (MN17), and Bacillus sp. (MN54). The vase life of French marigold was promoted by 66.6% in the individual application of PsJN and 100% in plants treated with consortium compared to the uninoculated control. The shoot and root fresh weights were also increased by 65.9 and 68.7%, with the combined application of all three strains. The total phenolics, flavonoid, and protein contents were higher in consortium treatment with an increase of up to 38.0, 55.9, and 65.9%, respectively, compared to the uninoculated control. Furthermore, combined application of endophytic bacterial strains promoted DPPH radical scavenging, mortality of plant-parasitic nematodes, and ferric reducing antioxidant power activities with increase of up to 278.0, 103.8, and 178.0%, respectively, compared to uninoculated control. An increase in antioxidant activities of ascorbate peroxidase (APX), catalase (CAT), glutathione peroxidase (GPX), and superoxide dismutase (SOD) were observed up to 77.3, 86.0, 91.6, and 102.9%, respectively by combined application of endophytic bacterial strains. So, given the economic importance of floriculture crops, endophytic bacterial isolates studied here have shown a great potential for improving the productivity of cultivated ornamental French marigold.

Phytohormone Production by the Endophyte Bacillus safensis TS3 Increases Plant Yield and Alleviates Salt Stress

“…The high halotolerance among the endophytes themselves for plants growing in a salty environment suggests that the plant can more easily adapt to stress along with different bacterial populations [ 17 , 18 ]. Therefore, endophytic bacteria can be used as biofertilizers, alleviating salt stresses due to their direct interaction with the host plant, leading to less competition with other microbes [ 19 , 20 , 21 , 22 ].…”

In Vitro and In Planta Antagonistic Effect of Endophytic Bacteria on Blight Causing Xanthomonas axonopodis pv. punicae: A Destructive Pathogen of Pomegranate

“…The significant impact of endophytes on the defense response of host plants against pathogens might be through early detection of pathogens by host plant cell surface receptor kinases, through cytoplasmic kinase-mediated intercellular responses, and by triggering of ethylene and jasmonic acid transduction pathways [ 24 , 50 ]. Zhao et al [ 50 ] and Naveed et al [ 51 ] reported the enhanced shoot and root growth, fresh and dry weight, and chlorophyll, phenol, protein, and cellulose contents of tissues, in endophytic microbe-inoculated plants. More detailed studies to unveil the exact mechanism via which endophytes antagonize Xap pathogen are required in future.…”

Microbial fortification of pharmacological metabolites in medicinal plants

“…(Saffron crocus) [65] Polyphenols Liquiritin Rhodoplanes Roots Glycyrrhiza uralensis Fisch [52] * Liquiritin Bacillus amyloliquefaciens FZB42 Roots Glycyrrhiza uralensis Fisch [55] Calycosin-7-glucoside Phyllobacterium Inquilnus Roots Astragalus mongholicus [59] * Kaempferol-7-O-glucoside Kaempferol3,7-di-O-glucoside Ruminococcaceae bacterium GD7 Roots Paeonia lactiflora Pall [71] * Flavonoids Ruminococcaceae Leaves Ginkgo biloba [73] * Piceatannol, kyotorphin Burkholderia ambifaria LK-P4 Leaves Anoectochilus roxburghii [75] Flavonoids, total polyphenols Bacteria consortium Flowers Tagetes patula L . (French marigold) [76] Alkannin/shikonin Labrys Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium Penicillium (fungus) Roots Alkanna tinctoria L . [77] * Alkannin/shikonin Chitinophaga sp.…”

“…In Anoectochilus roxburghii that produces kyotorphin and piceatannol, the bacteria treatment with Burkholderia ambifaria LK-P4 increased the plant contents of these two phenolic compounds, which can significantly decrease blood glucose levels and protect the organs of mice with similar effects of glibenclamide tablet, a standard drug for the symptomatic treatment of diabetic mice [75] . In French marigold ( Tagetes patula L.) that is used for skin and digestive conditions, the treatment of an endophytic bacteria consortium resulted in 56 % and 38 % in the contents of flavonoids and total polyphenols, respectively [76] .…”