Amri, M. | bioRxiv Science

bioRxiv2020

Chlorophyll content and chlorophyll fluorescence as physiological parameters for monitoring Orobanche foetida Poir. infestation on faba bean (Vicia faba L.)

In total, 39 faba bean (Vicia faba L.) advanced lines were evaluated for resistance to broomrape Orobanche foetida under highly infested field conditions. The trials were conducted during two consecutive copping seasons at Oued-Beja Research Station in Tunisia. The advanced lines XAR-VF00.13-1-2-1-2-1 and XBJ90.04-2-3-1-1-1-2A expressed high resistance level to O. foetida exceeding those recorded for resistance checks Najeh and Baraca. Results showed that O. foetida significantly affected the biomass, grain yield, chlorophyll content index (CCI) and the maximum quantum efficiency (Fv/Fm ratio). No significant effect of O. foetida parasitism was observed on host plant water content (WC). O. foetida parasitism significantly affected both CCI and Fv/Fm ratio. CCI decreases varied from 46.4% for the susceptible check Badi and 4.2% and 9.3% observed for the genotypes Baraca and XBJ90.04-2-3-1-1-1-2A. Compared to susceptible check, slight decreases of Fv/Fm ratio were observed for both advanced lines XBJ90.04-2-3-1-1-1-2A and XAR-VF00.13-1-2-1-2-1. Correlation between CCI and Fv/Fm with the resistance to broomrape makes this, easy-to-measure, parameter very useful as a practical screening tool for early parasitism detection, diagnosis and identification and selection of high resistant plants against this pathogen.

genetics↗

bioRxiv2018

Octadecaneuropeptide prevents toxicity induced by 6-hydroxydopamine in cultured rat astrocyte: involvement of the endogenous antioxidant systems and the intrinsic apoptotic pathway

Oxidative stress, associated with various neurodegenerative diseases, induces imbalance in ROS generation, impairs cellular antioxidant defences and finally triggers both neurons and astroglial cell death by apoptosis. Astrocytes specifically synthesize and release endozepines, a family of regulatory peptides, including the octadecaneuropeptide (ODN). We have previously reported that ODN is a potent neuroprotective agent that prevents 6-OHDA-induced apoptotic neuronal death. The purpose of the present study was to investigate the potential glioprotective effect of ODN on 6-OHDA-induced oxidative stress and cell death in cultured rat astrocytes. Incubation of astrocytes with graded concentrations of ODN (10-14 to 10-8 M) inhibited 6-OHDA-evoked cell death in a concentration- and time-dependent manner. In addition, ODN prevented the decrease of mitochondrial activity and caspase-3 activation induced by 6-OHDA. Toxin-treated cells exhibited high level of ROS associated with a generation of H2O2 and O2{degrees}-and a reduction of both SOD and catalase activities. Co-treatment of astrocytes with low concentrations of ODN dose dependently blocked 6-OHDA-evoked ROS production and inhibition of antioxidant enzymes activities. Taken together, these data demonstrate that ODN is a potent glioprotective agent that prevents 6-OHDA-induced oxidative stress and apoptotic cell death. ODN is thus a potential candidate to delay neuronal damages in various pathological conditions involving oxidative neurodegeneration.

cell biology↗