Genetic Determinants of Antagonistic Interactions and the Response of New Endophytic Strain Serratia quinivorans KP32 to Fungal Phytopathogens

Abstract

Fungal phytopathogens are challenging to control due to their penetration into plant tissues. Therefore, plant-colonizing bacteria could serve as an excellent weapon in fighting fungal infections. In this study, we aim to determine the biocontrol potential of the new endophytic strain Serratia quinivorans KP32, isolated from the roots of Petroselinum crispum L.; identify the related mechanisms; and understand the basis of its antagonistic interaction with taxonomically diverse fungi at the molecular level. The KP32 strain presented biological activity against Rhizoctonia solani, Colletotrichum dematium, Fusarium avenaceum, and Sclerotinia sclerotiorum, and its ability to inhibit the growth of the phytopathogens was found to be mediated by a broad spectrum of biocontrol features, such as the production of a number of lytic enzymes (amylases, chitinases, and proteases), siderophores, volatile organic and inorganic compounds, salicylic acid, and N-acyl-homoserine lactones. The higher expression of chitinase (chiA) and genes involved in the biosynthesis of hydrogen cyanide (hcnC), enterobactin (entB), and acetoin (budA) in bacteria exposed to fungal filtrates confirmed that these factors could act in combination, leading to a synergistic inhibitory effect of the strain against phytopathogens. We also confirm the active movement, self-aggregation, exopolysaccharide production, and biofilm formation abilities of the KP32 strain, which are essential for effective plant colonization. Its biological activity and colonization potential indicate that KP32 holds tremendous potential for use as an active biopesticide and plant growth promoter.

Probing the potential of salinity-tolerant endophytic bacteria to improve the growth of mungbean [Vigna radiata (L.) Wilczek]

“…P. extremorientalis improved plant growth under salt stress by reducing harmful effects of salt ( Egamberdieva et al, 2016 ). Recently, researchers have revealed the existence of S. quinivorans in the oak, Petroselinum crispum and Picrorhiza kurroa ( Kumar et al, 2021 ; Reis et al, 2021 ; Chlebek et al, 2022 ). Novel plant-bacterial associations might be due to the changes in environmental conditions.…”

Culturable endophytic Sordariomycetes from Rosa roxburghii: New species and lifestyles

“…The first three refer to one or more specified in the literature, as reported by Ariyawansa et al (2015). If not, in this work, endophytic fungi are those isolated from healthy plants by surface sterilization; saprophytic fungi substrate on dead or decaying plant material, soil, water, dung, and air; opportunistic plant pathogenic fungi, when reported in the literature, are isolated from plant tissues showing obvious disease symptoms, such as spots, blights, wilts, and/or rots (Chlebek et al, 2022). Others belong to unknown lifestyles, mainly where the substrate is unknown or only known from a plant substrate but cannot be assumed from the methods and results.…”