title: A consortium of rhizobacterial strains and biochemical growth elicitors improve cold and drought stress tolerance in rice (Oryza sativa L.).
abstract: In the present study, a consortium of two rhizobacteria Bacillus amyloliquefaciens Bk7 and Brevibacillus laterosporus B4, termed 'BB', biochemical elicitors salicylic acid and β-aminobutyric acid (SB) and their mixture (BBSB) were investigated for cold and drought stress tolerance in rice plants. After withholding water for 16 days, rice plants treated with BBSB showed 100% survival, improved seedling height (35.4 cm), shoot number (6.12), and showed minimum symptoms of chlorosis (19%), wilting (4%), necrosis (6%) and rolling of leaves. Similarly, BB inoculation enhanced plant growth and reduced overall symptoms in rice seedlings subjected to 0 ± 5 °C for 24 h. Our results imply several mechanisms underlying BB- and BBSB-elicited stress tolerance. In contrast to the control, both treatments significantly decreased leaf monodehydroascorbate (MDA) content and electrolyte leakage, and increased leaf proline and cholorophyll content. Moreover, activities of antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT) increased 3.0- and 3.6-fold, respectively. Moreover, expression of OsMYB3R-2, OsDIL, OsDREB1A and OsCDPK13 genes was significantly up-regulated, suggesting that these genes play important roles in abiotic stress tolerance of rice. In addition, bacterial strains Bk7 and B4 were able to produce high amounts of IAA and siderophores, and colonise the plant roots, while only strain Bk7 exhibited the capability to form biofilms and solubilise inorganic phosphate. This study indicates that the BB and BBSB bio-formulations can be used to confer induced systematic tolerance and improve the health of rice plants subject to chilling and drought stress.
authors.affiliation: State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China.|College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China.|Guizhou Academy of Tobacco Science, Guiyang, China.
authors.forename: K U
authors.initials: KU
authors.lastname: Kakar
authors.affiliation: Guizhou Academy of Tobacco Science, Guiyang, China.
authors.forename: X-L
authors.initials: XL
authors.lastname: Ren
authors.affiliation: Guizhou Academy of Tobacco Science, Guiyang, China.
authors.forename: Z
authors.initials: Z
authors.lastname: Nawaz
authors.affiliation: State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China.|College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China.
authors.forename: Z-Q
authors.initials: ZQ
authors.lastname: Cui
authors.affiliation: State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China.|College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China.
authors.forename: B
authors.initials: B
authors.lastname: Li
authors.affiliation: State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China.|College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China.
authors.forename: G-L
authors.initials: GL
authors.lastname: Xie
authors.affiliation: University of Maiduguri, Maiduguri, Nigeria.
authors.forename: M A
authors.initials: MA
authors.lastname: Hassan
authors.affiliation: College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China.
authors.forename: E
authors.initials: E
authors.lastname: Ali
authors.affiliation: State Key Laboratory Breeding Base for Zhejiang Sustainable Plant Pest and Disease Control, Key Laboratory of Detection for Pesticide Residues, Ministry of Agriculture, Zhejiang Academy of Agricultural Sciences, Hangzhou, China.
authors.forename: G-C
authors.initials: GC
authors.lastname: Sun
mesh_terms: D000613:Aminobutyrates / Q000378:metabolism*; D000975:Antioxidants / Q000378:metabolism; D000069977:Bacillus amyloliquefaciens / Q000502:physiology*; D058675:Brevibacillus / Q000502:physiology*; D002374:Catalase / Q000378:metabolism; D003080:Cold Temperature; D055864:Droughts; D012275:Oryza / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D018515:Plant Leaves / Q000187:drug effects / Q000201:enzymology / Q000502:physiology; D018517:Plant Roots / Q000187:drug effects / Q000201:enzymology / Q000502:physiology; D011392:Proline / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism; D017262:Siderophores / Q000378:metabolism; D013312:Stress, Physiological; D013482:Superoxide Dismutase / Q000378:metabolism; D014867:Water / Q000378:metabolism
chemical_list: D000613:Aminobutyrates; D000975:Antioxidants; D017262:Siderophores; D014867:Water; C047667:3-aminobutyric acid; D011392:Proline; D002374:Catalase; D013482:Superoxide Dismutase; D020156:Salicylic Acid
keywords: Biochemical growth elicitors; bio-formulation; cold and drought stress; gene expression; induced resistance; rice