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Rhizosphere‐associated Alcaligenes and Bacillus strains that induce resistance against blast and sheath blight diseases, enhance plant growth and improve mineral content in rice
Author(s) -
Kakar K.U.,
Nawaz Z.,
Cui Z.,
Almoneafy A.A.,
Ullah R.,
Shu Q.Y.
Publication year - 2018
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/jam.13678
Subject(s) - bacillus amyloliquefaciens , biology , siderophore , rhizoctonia solani , rhizobacteria , microbiology and biotechnology , alcaligenes faecalis , rhizosphere , horticulture , food science , bacteria , fermentation , genetics
Aims To examine the biocontrol activities of five rhizobacterial strains (i.e. Alcaligenes faecalis strains Bk1 and P1, Bacillus amyloliquefaciens strain Bk7 and Brevibacillus laterosporus stains B4 and S5), to control the rice blast and sheath blight diseases in greenhouse and to study their possible modes of action. Methods and Results Five potential plant growth‐promoting rhizobacterial (PGPR) strains isolated from rice rhizospheres were tested for in vitro antifungal activities against Magnaporthe oryzae , Rhizoctonia solani , Botrytis cinerea and Fusarium graminearum. In vitro trials showed that three strains, Bk1, P1 and Bk7, were able to unanimously suppress the mycelial growth of the target pathogens. In greenhouse, the application of these three PGPR strains significantly suppressed the incidences of rice blast and sheath blight diseases. At 2 weeks after pathogen inoculation, the highest percentages of disease suppression were noted for Alc. faecalis strain Bk1 (72%) for rice blast, Alc. faecalis strain P1 (71%) for sheath blight, followed by B. amyloliquefaciens strain Bk7. Moreover, these strains significantly improved the plant growth, enriched the content of mineral nutrients in seedlings and increased the expression of major defence‐related rice genes. All three strains were marked positive for phosphate solubilization, the production of indoleacetic acid, ammonia and siderophores and catalase activity. In addition, these strains were able to form biofilms and carried multiple lipopeptide biosynthetic genes as revealed by multiplex PCR. Conclusion This study reports new potential biocontrol agents for blast and sheath blight diseases of rice. Significance and Impact of the Study This study contributes to better understanding of the mechanisms involved in interaction between beneficial rhizobacteria, fungal pathogens and host plants.