Minimal promoter for the NAD+-specific glutamate dehydrogenase gene of Neurospora crassa.

The expression of the NAD+-specific glutamate dehydrogenase (NAD-GDH) gene of Neurospora crassa is subject to catabolite repression. To identify the minimal sequence necessary for promoter function, the 5'-flanking region of the NAD-GDH gene was screened for potential protein-binding sites. Fragments of DNA, containing sequences upstream from the ATG initiation codon, were employed as probes of Southwestern blots of total cellular protein from cells grown in media promoting repression and induction of NAD-GDH. Two polypeptides interacted differentially with a promoter probe; one was present in greater abundance in repressed cells and a higher relative level of the second was witnessed in induced cells. Electrophoretic mobility shift assays with labeled promoter fragments exhibited preferential interaction with proteins in the induced cultures. The upstream sequence containing the putative protein-binding sites was fused with the coding sequence of the green fluorescent protein (GFP). The resulting plasmid was introduced into the microconidia of an albino mutant of N. crassa by electroporation. Stable integration of the plasmid and_expression of GFP in the hyphae and conidia of the transformants were demonstrated by Southern and Western blot analysis and fluorescence microscopy.     

Recent Perspectives on Cross Talk Between Cadmium,Zinc, and Arbuscular Mycorrhizal Fungi in Plants

Journal of Plant Growth Regulation - Soils polluted with heavy metals result into various environmental and ecological tribulations like alterations in microbial community, deterioration of soil,...     

Exogenously applied spermidine confers protection against cinnamic acid-mediated oxidative stress in Pisum sativum

This study investigated the stress responses of cinnamic acid (CA) in pea plants and explored the protective role of spermidine (SPD) against CA-induced adverse effects. Pea seedlings exposed to CA had reduced length, biomass, moisture, chlorophyll, sugar, and protein contents and reduced nitrate reductase activity. These parameters increased when SPD was applied alone and in combination with CA. Electrolyte leakage and malondialdehyde content were high in seedlings treated with CA but decreased when the SPD + CA treatment was applied. Foliar exposure to SPD partially mitigated CA-induced stress effects by strengthening the antioxidant defense system, which helped preserve the integrity of biochemical processes. These results indicate that SPD (1 mM) could mitigate the adverse effects of CA and enhance plant defense system. Hence, SPD can be used as a growth regulator for the maintenance of physiological functions in pea plants in response to the pernicious consequences of CA stress.