Application of Bacterial Endophytes to Control Bacterial Leaf Blight Disease and Promote Rice Growth

Abstract

Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial leaf blight (BLB) disease in rice (Oryza sativa L.) and it is among the most destructive pathogen responsible for severe yield losses. Potential bacterial biocontrol agents (BCAs) with plant growth promotion (PGP) abilities can be applied to better manage the BLB disease and increase crop yield, compared to current conventional practices. Thus, this study aimed to isolate, screen, and identify potential BCAs with PGP abilities. Isolation of the BCAs was performed from internal plant tissues and rhizosphere soil of healthy and Xoo-infected rice. A total of 18 bacterial strains were successfully screened for in vitro antagonistic ability against Xoo, siderophore production and PGP potentials. Among the bacterial strains, 3 endophytes, Bacillus sp. strain USML8, Bacillus sp. strain USML9, and Bacillus sp. strain USMR1 which were isolated from diseased plants harbored the BCA traits and significantly reduced leaf blight severity of rice. Simultaneously, the endophytic BCAs also possessed plant growth promoting traits and were able to enhance rice growth. Application of the selected endophytes (BCAs-PGP) at the early growth stage of rice exhibited potential in suppressing BLB disease and promoting rice growth.

The potential of beneficial microbes to suppress the development of bacterial leaf blight in rice plants caused by Xanthomonas oryzae pv. oryzae

“…Control of BLB using bactericides can potentially suppress BLB disease in the field. However, the continuous use of bactericides harms the environment, triggers resistance to pathogens, and impacts human health (Ooi et al 2022).…”

Genome insights from the Amazonian rhizobacterium Bacillus paramycoides RZ3MS14 reveal plant growth-promoting multi-traits and bioprotection against phytopathogens and environmental stresses

“…It has shown previously ability to produce indole-acetic acid (IAA) under in vitro assays (Batista et al 2018). This species belongs to the Bacillus cereus group, a subdivision of the genus Bacillus (Liu et al 2017), and certain isolates identi ed through 16S rDNA sequence analysis have attained notoriety as PGPB, especially in root development (Ooi et al 2022). Activities of phosphorus (P) and potassium (K) solubilization, ACC deaminase, hydrogen cyanide, production of phytohormones (IAA, ABA, benzyl, cytokinins, and gibberellins), siderophores, and secretion of various lytic enzymes, have been carried out by this species under in vitro or greenhouse conditions.…”

“…B. paramycoides strains have also been promising for the biocontrol of phytopathogens such as Fusarium oxysporum and Xanthomonas oryzae pv. oryzae (El-Sersawy et al 2021; Ooi et al 2022), in the degradation of acephate and methomyl widely used in agricultural pesticides (Omeiri et al 2022;Ren et al 2020), and the reduction of heavy metals to less toxic forms (Borah et al 2021) or by assisting the host as phytoremediator . Furthermore, research efforts have demonstrated its biotechnological applications.…”