Evaluating the augmented effect of potential plant growth promoting cyanobacterial strains on salinity and insecticidal stress tolerance of Oryza sativa L. under hydroponic cultivation

• Published in: Journal of applied phycology 2024-08, Vol.36 (4), p.1885-1899
• Main Authors: Gayathri, Manickam, Shunmugam, Sumathy, Sridhar, Jayavel, Muralitharan, Gangatharan
• Format: Article
• Language: English
• Subjects: Agrochemicals; Biodegradation; Biofertilizers; Biomedical and Life Sciences; Carotenoids; Chemical fertilizers; Chlorpyrifos; Crop growth; Cyanobacteria; Degradation products; Ecology; Environmental degradation; Environmental impact; Fertilizers; Freshwater & Marine Ecology; Herbicides; Hydroponics; Insecticides; Life Sciences; Nostoc; Nostoc commune; Oryza sativa; Pesticides; Plant growth; Plant growth substances; Plant hormones; Plant Physiology; Plant Sciences; Rice fields; Salinity; Salinity effects; Scytonema; Seedlings; Sodium chloride; Soil; Soil chemistry; Soil degradation; Soil fertility; Soil pollution; Soil stresses; Trichloro-2-pyridinol
• ISSN: 0921-8971; 1573-5176
• DOI: 10.1007/s10811-024-03251-9

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.