Evaluating the efficacy of endophytic bacteria in controlling rice sheath blight: In vitro and In vivo studies.

Publisher: Academic Press Country of Publication: England NLM ID: 8606191 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1096-1208 (Electronic) Linking ISSN: 08824010 NLM ISO Abbreviation: Microb Pathog Subsets: MEDLINE

Original Publication: London ; Orlando : Academic Press, c1986-

Oryza*/microbiology ; Plant Diseases*/microbiology ; Plant Diseases*/prevention & control ; Endophytes*/isolation & purification ; Endophytes*/metabolism ; Endophytes*/physiology ; Endophytes*/classification ; Endophytes*/genetics ; Rhizoctonia*/physiology ; Rhizoctonia*/growth & development ; Ascomycota*/physiology ; Ascomycota*/genetics ; Plant Roots*/microbiology ; Plant Leaves*/microbiology ; Antibiosis*; Indoleacetic Acids/metabolism ; Plant Growth Regulators/metabolism ; RNA, Ribosomal, 16S/genetics ; Bacillus/genetics ; Bacillus/physiology ; Bacillus/isolation & purification ; Bacillus/metabolism ; Biological Control Agents ; Gibberellins/metabolism ; Plant Stems/microbiology

Rice production is highly susceptible to various pathogens, including Rhizoctonia solani, Curvularia lunata, and Epicoccum rostratum, which are major threats in Asia. Exploring biological control methods using endophytic bacteria offers promising opportunities to enhance rice resilience against these lethal diseases. Using 16S RNA sequencing, we identified four endophytic isolates of Bacillus spp. from rice roots, stems, and leaves. We evaluated the antagonistic activity of these endophytic bacterial isolates against rice pathogens both in vitro and in vivo. These isolates inhibited the growth of C. lunata by 82 %, R. solani by 79 %, and E. rostratum by 88 % in vitro. The detached leaf assay for sheath blight (ShB) disease severity in strains ranged from 10.4 % to 73.3 %. In vivo results showed that B. amyloliquefaciens (R-19) exhibited the lowest disease intensity at 7.2 % and the highest disease suppression at 78.8 %. The fungicide propiconazole at 0.1 % treatment showed the lowest disease intensity of 7.7 % and the highest disease suppression of 73.4 %, compared to the infected control. Besides biocontrol efficacy, endophytic isolates enhance plant growth parameters, including shoot height, root length, fresh and dry weights, number of tillers, and grains per tiller. Plant hormones abscisic acid (ABA) and gibberellic acids (GA 3 ) increased by 35 % and 53 %, respectively, due to B. subtilis (R-20) and B. amyloliquefaciens (R-19), while flavonoid and indole acetic acid (IAA) concentrations surged by 30%-80 %. Similarly, chlorophyll (a, b), carotenoids, antioxidant enzymatic activity, phenolic content, carbohydrates, and proline contents were higher compared to the control. This study provides a foundation for future studies on novel and eco-friendly biocontrol agents. In addition, our study recommends the integration of endophytic bacteria into sustainable agriculture for enhancing rice production and reducing disease impacts.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024 Elsevier Ltd. All rights reserved.)

Keywords: Antagonistic activity; Bio-control; Endophytic bacteria; Plant growth-promoting bacteria; Sheath blight disease

0 (Indoleacetic Acids)
0 (Plant Growth Regulators)
0 (RNA, Ribosomal, 16S)
6U1S09C61L (indoleacetic acid)
0 (Biological Control Agents)
0 (Gibberellins)
BU0A7MWB6L (gibberellic acid)

Rhizoctonia solani

Date Created: 20241104 Date Completed: 20241201 Latest Revision: 20241201

20241204

10.1016/j.micpath.2024.107084

39490941