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Molybdate uptake and molybdenum cofactor (Moco) biosynthesis were investigated in detail in the last few decades. The present study critically reviews our present knowledge about eukaryotic molybdate transporters (MOT) and focuses on the model plant Arabidopsis thaliana, complementing it with new experiments, filling missing gaps, and clarifying contradictory results in the literature. Two molybdate transporters, MOT1.1 and MOT1.2, are known in Arabidopsis, but their importance for sufficient molybdate supply to Moco biosynthesis remains unclear. For a better understanding of their physiological functions in molybdate homeostasis, we studied the impact of mot1.1 and mot1.2 knock-out mutants, including a double knock-out on molybdate uptake and Moco-dependent enzyme activity, MOT localisation, and protein–protein interactions. The outcome illustrates different physiological roles for Moco biosynthesis: MOT1.1 is plasma membrane located and its function lies in the efficient absorption of molybdate from soil and its distribution throughout the plant. However, MOT1.1 is not involved in leaf cell imports of molybdate and has no interaction with proteins of the Moco biosynthesis complex. In contrast, the tonoplast-localised transporter MOT1.2 exports molybdate stored in the vacuole and makes it available for re-localisation during senescence. It also supplies the Moco biosynthesis complex with molybdate by direct interaction with molybdenum insertase Cnx1 for controlled and safe sequestering. [ABSTRACT FROM AUTHOR] more...

Plants encounter various biotic and abiotic stresses at different growth stages throughout their life. To grapple and adjust with persisting stress conditions, plants have developed certain mechanisms through the mean of transcription. Transcription factors manipulate the feat of multiple stress response in a contemporized way. Among them, drought resistant element binding proteins DREB may act as a defense impediment to minimize plant water loss. The DREB2 gene (PTTa00075.1) amplified from wheat cv. Chinese spring was cloned in pCAMBIA 1304 under the control of CaMV35S promoter. To modify the genome and plant traits, Agrobacterium-mediated transformation may transmit the desired genes. The transgenic tobacco plants harboring the desired gene were developed through tissue culture technique. The GUS (β-glucuronidase) staining confirms the gene transformation. The putative transgenic plants were selected on selective antibiotic (hygromycin) media. The PCR analysis of T1 generation confirmed the incorporation of the transgene into the tobacco genome for further evaluation. [ABSTRACT FROM AUTHOR] more...