Nitric oxide production and its functional link with OIPK in tobacco defense response elicited by chitooligosaccharide

Abstract

Chitooligosaccharide (COS) or oligochitosan has been shown to induce tobacco defense responses which are connected with nitric oxide (NO) and OIPK (oligochitosan-induced Ser/Thr protein kinase). The aim of this study was to reveal the relationship between NO production and OIPK pathway in the defense response of tobacco elicited by COS. NO generation was investigated by epidermal strip bioassay and fluorophore microscope using fluorophore diaminofluorescein diacetate (DAF-2DA). Tobacco epidermal cells treated with COS resulted in production of NO, which was first present in chloroplast, then in nucleus, finally in the whole cell; this NO production was sensitive to NO scavenger cPTIO and the mammalian NO synthase (NOS) inhibitor L-NAME, suggesting that NOS-like enzyme maybe involved in NO generation in tobacco epidermal cells. However, NOS and nitrate reductase (NR, EC 1.6.6.1) inhibitors reduced NO content in tobacco leaves by using NO Assay Kit, suggesting both NOS and NR were involved in NO production in tobacco leaves. Using a pharmacological approach and western blotting, we provide evidence that NO acts upstream of OIPK expression. NO scavenger, NOS inhibitor partly blocked the activation of OIPK and the activities of several defense-related enzymes induced by COS; treatment with NO donor sodium nitroprusside (SNP) induced the activation of OIPK and enhanced the defense systems. The results suggest that COS is able to induce NO generation, which results in up-regulation the activities of some defense-related enzymes through an OIPK-dependent or independent pathway.

Biostimulant activity of chitosan in horticulture

“…These findings suggest that both ROS and NO production lead to defense responses in plants. Zhang et al (2011) reported that NO was first produced in the chloroplast, then in nucleus and later in the whole cell. Considering that tobacco cells treated with NO synthase and nitrate reductase (NR) inhibitors showed suppressed levels of NO production and several defense-related enzymes, this mechanism is proposed to be regulated by an NO synthase-like enzyme and NR .…”

“…Moreover, the plant defense system induced by chitosan was triggered via the nitric oxide (NO) pathway (Raho et al, 2011;Zhang et al, 2011;Zhao et al, 2007). In tobacco epidermis, oligochitosan could induce both NO and H 2 O 2 production (Fu et al, 2011).…”

Chitosan nanoparticle based delivery systems for sustainable agriculture

“…Chitosan has been demonstrated to induce plant defences in tomato [87,89], cucumber [97], chilli seeds [102], strawberry fruits [88] and rose shrubs [99]. Chitosan can activate innate immunity by stimulating hydrogen peroxide (H 2 O 2 ) production in rice [134,135], induce a defense response by nitric oxide (NO) pathways in tobacco [136,137], promote the development and drought resistance of coffee [138], support the synthesis of phytoalexin [139], impact the jasmonic acid-ethylene (JA/ET) signaling marker in oilseed rape [140], cause changes in protein phosphorylation [141], activate mitogen-activated protein kinases (MAPKs) [142] and trigger Maize Induction in endogenous hormone content, alpha-amylase activity and chlorophyll content in seedling leaves [92] 2002 Mulberry Enhancement in respiration rate of germination seeds, root vigor, chlorophyll, protein content and peroxidase in seedlings as well as nitrate reductase and amylase activities [93] 2002 Cucumber, Chilli, pumpkin, and cabbage Increment in the seed germination rate [94] 2002 Peanut Enhancement in the energy of germination and germination percentage [95] Grape Direct antifungal activity against Botrytis bunch rot and induction of defense-related enzymes activities [110] 2010…”

Effects of postharvest oligochitosan treatment on anthracnose disease in citrus (Citrus sinensis L. Osbeck) fruit

“…According to some published papers, Ca 2+ , reactive oxygen species (ROS), nitric oxide (NO), jasmonic acid (JA), and salicylic acid (SA) are all involved in the oligochitosan-activated signaling pathway [6,8,9,19,20]. An oligochitosan-induced protein kinase (OIPK) has been previously isolated and identified in tobacco [21,22]. The above findings suggest that oligochitosan is a promising alternative to synthetic fungicides to control postharvest diseases in horticultural products.…”