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A consortium of rhizobacterial strains and biochemical growth elicitors improve cold and drought stress tolerance in rice ( Oryza sativa L.)
Author(s) -
Kakar K. U.,
Ren X.l.,
Nawaz Z.,
Cui Z.Q.,
Li B.,
Xie G.L.,
Hassan M. A.,
Ali E.,
Sun G.C.
Publication year - 2016
Publication title -
plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 1435-8603
DOI - 10.1111/plb.12427
Subject(s) - biology , oryza sativa , seedling , catalase , chlorosis , rhizobacteria , proline , shoot , salicylic acid , horticulture , superoxide dismutase , drought tolerance , botany , antioxidant , rhizosphere , gene , bacteria , amino acid , biochemistry , genetics
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 Os MYB 3R ‐2, Os DIL , Os DREB 1A and Os CDPK 13 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.