Nostoc sp. extract induces oxidative stress-mediated root cell destruction in Mimosa pigra L.

Abstract

BackgroundMimosa pigra is an invasive weed in some regions of South East Asia and Australia. Our previous study has revealed that a cyanobacterium, Nostoc sp., extract can inhibit root growth in M. pigra seedlings. In this study, some physiological processes involve oxidative stress-mediated cell death and root ultrastructure were investigated to clarify the mechanisms of root growth suppression and bioherbicidal potential of the extract.ResultsNostoc sp. extract enhanced overproduction of reactive oxygen species (ROS) at 24 h, the intensity of red fluorescence increased at 72 h, and caused a slightly increased H2O2 consistent with the activation of scavenging enzymes (catalase, ascorbic acid peroxidase, glutathione reductase, and peroxidases). This suggests that oxidative stress occurred in the presence of the extract which was supported by increased cell death and lipid peroxidation at 24 h. Reduction of malondialdehyde content and an increase in cell death at 72 h indicated oxidative damage and cellular leakage. Ultrastructural changes were determined at 72 h by scanning electron micrographs which confirmed the damage of epidermal and root cap cells and the disaggregation and destruction of root tip cells. Transmission electron micrographs showed the dissolution of the middle lamella, deposition of some substances in vacuoles, and abnormal mitochondria (swollen mitochondria and indistinct cristae).ConclusionsNostoc sp. extract enhance oxidative stress by ROS production resulting in lipid peroxidation and massive cell death despite the activation of antioxidative enzymes. Understanding mechanism of action of Nostoc sp. extract will provide information for application of the extract to use as natural herbicide for control of M. pigra.Electronic supplementary materialThe online version of this article (doi:10.1186/s40529-014-0081-3) contains supplementary material, which is available to authorized users.

Accumulation of Flavonoids in Soybean Under Effects of Cyanobacterial Crude Extract and Aphid Infestation

“…Nostoc cells were cultured in BG11 medium, pH 6.5 at temperature of 32 ± 2°C, under daylight fluorescent lamps, light period of 14 light/10 dark [3].…”

“…The dried cells were ground to powder and extracted with 80 % methanol for 24 hours. The solution was centrifuged by 10,000 × g in 15 min to collect supernatant that was evaporated to obtain a crude brown gum [3].…”

“…have been identified as cytotoxic, antifungal, antibacterial, antiviral, immunosuppressive, enzyme inhibiting activities in the effect on higher plants [2]. Extract of some Nostoc species induces oxidative stress in plant cells by reactive oxygen species (ROS) productions resulting in lipid peroxidation and massive cell death as well as activating enzymatic antioxidants [3]. In our recent publication mentioned about the effect of strain N. calcicola HN9 on the antioxidant system of soybean "Nam Dan" (Glycine max (L.) Merr.…”

Antioxidant modulation in response to selenium induced oxidative stress in unicellular cyanobacterium Synechococcus elongatus PCC 7942

“…GPX activity was assayed by coupling the oxidation of glutathione to NADPH oxidation in the presence of t-butyl H2O2 as following the decrease in absorbance at 340 nm (Bagchi et al, 2012). The GR activity was determined according to Sukkhaeng et al (2015) by measuring the reduction of oxidized glutathione by quantifying NADPH oxidation at 340 nm. Cell free extract equivalent to 75 µg protein was used as the enzymatic source for all the aforementioned enzyme assays.…”

Nostoc calcicola extract improved the antioxidative response of soybean to cowpea aphid

“…Extract of Nostoc sp. induced oxidative stress by accumulating reactive oxygen species (ROS), causing massive cell death in Mimosa pigra (Sukkhaeng et al 2015 ). Contrary, an in vitro study of Li and co-workers ( 2007 ) demonstrated that Nostoc species have their ability to scavenge ROS and inhibit lipid peroxidation.…”