Functional loss of GABA transaminase (GABA-T) expressed early leaf senescence under various stress conditions in Arabidopsis thaliana

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“…[8,24,25] It has been also studied that wild type of A. thaliana is more tolerant to oxidative stress, as compared to pop2-3 mutant of GABA-T stress, and morphology of pop2-3 mutant might differ to wild type plants. [9,15,17,26] The oversensitivity of the pop2-3 mutants to the abiotic and oxidative stress treatment indicates that a GABA-T defect impaired GABA accumulation that might be required for growth and implicates that GABA is involved in intracellular signalling, especially during leaf senescence under stress conditions. T-DNA insertion pop2-3 mutant of A. thaliana displays reduced seed production under selffertilization, implying that the role of this enzyme is restricted to flower tissue.…”

“…[29] We have previously established physiological parameters for the screening of leaf senescence that based on the determination of chlorophyll content, ion leakage, and MDA content at different leaf developmental stages. [15] We have compared the physiological characteristics associated with senescence to the wild-type, pop2-3 mutant, and GABA-T complement plant of A. thaliana. Chlorophyll can provide basic information of photosynthesis, and chlorophyll degradation is an important feature of senescence.…”

“…Based on screening of senescence parameters, we showed that knockout of the GABA-T causes enhanced accumulation of reactive oxygen species and cell death in response to different stress conditions. [15] In the present study, we have investigated the function of A. thaliana GABA-T gene in leaf senescence by functional complementation of GABA-T into pop2-3 T-DNA insertion mutant in conjunction with GABA-shunt component analysis. We demonstrate here that pop2-3 T-DNA insertion mutant expressed early leaf senescence than wild type, based on screening of senescence parameters.…”

“…[23] Quantification of GABA Content GABA was extracted and determined from frozen tissues of different developmental stages (10-, 20-, and 30-day-old plant) of wild-type, pop2-3 mutants, and complement plants; the GABA content in the sample was calculated based on the difference in absorbance. The standard GABA was prepared in micromole concentration and used for constructing the calibration graph as done in the previous study by Jalil et al [15] Determination of Enzyme (GABA-T and GAD) Activities GABA-T and GAD activities assay were performed from the protein that was extracted from the leaves of wild type, pop2-3 mutants, and complement plants of A. thaliana at different stages (10-, 20-, and 30-day-old plant) as described earlier by Jalil et al [15] …”

A magnetic affinity approach to identify plant GABA-binding proteins

“…In addition, GABA is a significant component of the free amino acid pool in plants and it is present in almost all organs. The intercellular GABA content can be increased quickly in response to biotic and abiotic stresses, such as cold, drought, salinity, extreme temperatures, oxidative stress, and fungal infections (Bouche et al, 2003;Jiang and Gu, 2003;Jalil et al, 2017). It has been postulated that GABA is an endogenous plant signaling molecule (Palanivelu et al, 2003;Yang, 2003).…”