Concurrent overexpression of rice G-protein β and γ subunits provide enhanced tolerance to sheath blight disease and abiotic stress in rice
Our study demonstrates that simultaneous overexpression of RGB1 and RGG1 genes provides multiple stress tolerance in rice by inducing stress responsive genes and better management of ROS scavenging/photosynthetic machineries.
The heterotrimeric G-proteins act as signalling molecules and modulate various cellular responses including stress tolerance in eukaryotes. The gamma (γ) subunit of rice G-protein (RGG1) was earlier reported to promote salinity stress tolerance in rice. In the present study, we report that a rice gene-encoding beta (β) subunit of G-protein (RGB1) gets upregulated during both biotic (upon a necrotrophic fungal pathogen, Rhizoctonia solani infection) and drought stresses. Marker-free transgenic IR64 rice lines that simultaneously overexpress both RGB1 and RGG1 genes under CaMV35S promoter were raised. The overexpressing (OE) lines showed enhanced tolerance to R. solani infection and salinity/drought stresses. Several defense marker genes including OsMPK3 were significantly upregulated in the R. solani-infected OE lines. We also found the antioxidant machineries to be upregulated during salinity as well as drought stress in the OE lines. Overall, the present study provides evidence that concurrent overexpression of G-protein subunits (RGG1 and RGB1) impart multiple (both biotic and abiotic) stress tolerance in rice which could be due to the enhanced expression of stress-marker genes and better management of reactive oxygen species (ROS)-scavenging/photosynthetic machinery. The current study suggests an improved approach for simultaneous improvement of biotic and abiotic stress tolerance in rice which remains a major challenge for its sustainable cultivation.
KeywordsAntioxidants Biotic stress Defense marker genes Drought stress G-protein MAP kinase Overexpression ROS R. solani Salinity stress
Empty vector control
Rice G-protein beta subunit1
Rice G-protein gamma subunit 1
Reactive oxygen species
DMS acknowledges post-doctoral fellowship from Department of Biotechnology (DBT), Govt. of India. Work on abiotic stress tolerance in NT laboratory is supported by the DBT, Government of India. SG acknowledges SPM fellowship from CSIR, India. RK acknowledges SRA fellowship from CSIR, India. Work in GJ lab was supported by core research grant from National Institute of Plant Genome Research, India and research funding from DBT, Govt. of India.
Compliance with ethical standards
Conflict of interest
The authors declare no competing financial interests. The seeds of OE lines can be freely obtained from the authors by following the regulatory guidelines associated with transgenic/genetically modified crops.
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