title: Overexpression of a novel SbMYB15 from Salicornia brachiata confers salinity and dehydration tolerance by reduced oxidative damage and improved photosynthesis in transgenic tobacco.
abstract: SbMYB15, R2R3-type MYB was induced by the different stresses, and conferred stress tolerance in transgenic tobacco by regulating the expression of stress-responsive genes. MYBs are the master regulators of various metabolic processes and stress responses in plants. In this study, we functionally characterised a R2R3-type SbMYB15 transcription factor (TF) from the extreme halophyte Salicornia brachiata. The SbMYB15 acts as a transcriptional activator. Transcriptional analysis showed that SbMYB15 transcript was strongly upregulated in red shoots and was also induced by different stresses; however, its expression remained unchanged with ABA. Overexpression of SbMYB15 in tobacco significantly improved salinity and dehydration tolerance. The enhanced tolerance of the transgenic plants was defined by the changes in chlorophyll, malondialdehyde (MDA), proline, total soluble sugar and total amino acid contents. The transgenic plants exhibited a higher membrane stability and reduced electrolyte leakage, H2O2 and O 2 (-) content compared to the wild type (WT). With ionic stress, transgenics showed a low Na(+) and a high K(+) content. In the transgenic plants, the expression of stress-responsive genes such as LEA5, ERD10D, PLC3, LTP1, HSF2, ADC, P5CS, SOD and CAT was enhanced in the presence of salinity, dehydration and heat. Exposure to gradual salinity and dehydration resulted in an increased stomatal conductance, water use efficiency, photosynthesis rate, photochemical quenching and reduced transpiration rate. Thus, SbMYB15 served as an important mediator of stress responses regulating different stress signalling pathways, leading to enhanced stress tolerance.
authors.affiliation: Division of Wasteland Research, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific & Industrial Research (CSIR), Gijubhai Badheka Marg, Bhavnagar, 364 002, Gujarat, India.|Academy of Scientific and Innovative Research, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific and Industrial Research (CSIR), Gijubhai Badheka Marg, Bhavnagar, 364 002, Gujarat, India.
authors.forename: Pushp Sheel
authors.initials: PS
authors.lastname: Shukla
authors.affiliation: Division of Wasteland Research, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific & Industrial Research (CSIR), Gijubhai Badheka Marg, Bhavnagar, 364 002, Gujarat, India.
authors.forename: Kapil
authors.initials: K
authors.lastname: Gupta
authors.affiliation: Division of Wasteland Research, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific & Industrial Research (CSIR), Gijubhai Badheka Marg, Bhavnagar, 364 002, Gujarat, India.
authors.forename: Parinita
authors.initials: P
authors.lastname: Agarwal
authors.affiliation: Division of Marine Biotechnology and Ecology, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific & Industrial Research (CSIR), Gijubhai Badheka Marg, Bhavnagar, 364002, Gujarat, India.|Academy of Scientific and Innovative Research, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific and Industrial Research (CSIR), Gijubhai Badheka Marg, Bhavnagar, 364 002, Gujarat, India.
authors.forename: Bhavanath
authors.initials: B
authors.lastname: Jha
authors.affiliation: Division of Wasteland Research, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific & Industrial Research (CSIR), Gijubhai Badheka Marg, Bhavnagar, 364 002, Gujarat, India. pagarwal@csmcri.org.|Academy of Scientific and Innovative Research, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific and Industrial Research (CSIR), Gijubhai Badheka Marg, Bhavnagar, 364 002, Gujarat, India. pagarwal@csmcri.org.
authors.forename: Pradeep K
authors.initials: PK
authors.lastname: Agarwal
mesh_terms: D015870:Gene Expression; D006861:Hydrogen Peroxide / Q000378:metabolism; D018384:Oxidative Stress; D030821:Plants, Genetically Modified / Q000378:metabolism* / Q000502:physiology; D054712:Salinity; D055051:Salt-Tolerant Plants / Q000378:metabolism / Q000502:physiology; D014026:Nicotiana / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology; D014157:Transcription Factors / Q000378:metabolism* / Q000502:physiology
chemical_list: D014157:Transcription Factors; D006861:Hydrogen Peroxide
keywords: Abiotic stress tolerance; Halophyte; Osmolyte; Photosynthesis; R2R3-type MYB transcription factor; Transcription factor