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Cyanobacteria are essential in paddy fields, aiding soil fertility. Soil pollution, caused by excessive chemical fertilizers and pesticides, poses a global crisis. To use cyanobacterial biofertilizers effectively, strains need to tolerate and break down these agrochemicals, including herbicides. This study examined the ability of potential plant growth promoting cyanobacterial strains Nostoc commune MBDU 101 and Scytonema bohneri MBDU 104 to tolerate salinity - NaCl (100 mM) and chlorpyrifos (5 mg L-1) stress of Oryza sativa L. grown under hydroponic conditions, both individually and in combination with each other. These cyanobacterial strains have already been proven for their ability to produce phytohormones and are now assessed for their salinity and insecticide tolerance through growth parameters, including chlorophyll, carotenoids, and protein content, over 24 days under test conditions. Those treatments that demonstrated optimal cyanobacterial growth were subsequently tested for their impact on O. sativa L. under hydroponic conditions along with a control group. Notably, N. commune MBU101 under chlorpyrifos stress showed distinctive positive effects on plant growth, with a shoot length of 3.18 cm, seedling length of 6.68 cm, 13 lateral roots, and a leaf length of 6.73 cm. Scytonema bohneri MBDU 104 (SB104) exposed to NaCl stress exhibited the highest seedling weight among all treatments and the control. GC-MS analysis of N. commune revealed the presence of 3,5,6-trichloro-2-methoxypyridine (TMP) and 3,5,6-trichloro-2-pyridinol (TCP) as degradation products of chlorpyrifos. These findings emphasize the potential of these cyanobacterial strains in enhancing soil health and crop growth while mitigating the environmental impact of agrochemicals. [ABSTRACT FROM AUTHOR]

Nodularin, a cyclic hepatotoxic pentapeptide produced by the nitrogen-fixing cyanobacterium Nodularia spumigena, induces oxidative stress in various organisms including higher plants and algae. We have monitored the physiological consequences of N. spumigena AV1 extract exposure on terrestrial plants, specifically focusing on the mitochondrial function of Spinacia oleracea L. Our results show that exposure of the plants to the nodularin-containing extract leads to significantly increased activity of respiratory complex I and citrate synthase, as well as increased accumulation of various subunits of respiratory enzyme complexes. Moreover, upregulation of the stress-induced alternative oxidase as well as the NAD-specific isocitrate dehydrogenase and mitochondrial ascorbate peroxidase was detected in the mitochondria of plants exposed to N. spumigena AV1 extract, while no difference in the carbonylation level of the mitochondrial proteins could be detected between the control and the exposed plants. [ABSTRACT FROM AUTHOR]