RNase Activity Prevents the Growth of a Fungal Pathogen in Tobacco Leaves and Increases upon Induction of Systemic Acquired Resistance with Elicitin

Abstract

The hypersensitive response and systemic acquired resistance (SAR) can be induced in tobacco (Nicotiana tabacum 1.) plants by cryptogein, an elicitin secreted by Pbytopbfbora crypfogea. Stem application of cryptogein leads to the establishment of acquired resistance to subsequent leaf infection with Pbytopbfbora parasitica var nicotianae, the agent of the tobacco black shank disease. We have studied early events that occur after the infection and show here that a tobacco gene encoding the extracellular S-like RNase NE is expressed in response to inoculation with the pathogenic fungus.Upon induction of SAR with cryptogein, the accumulation of NE transcripts coincided with a rapid induction of RNase activity and with the increase in the activity of at least two different extracellular RNases. Moreover, exogenous application of RNase activity in the extracellular space of leaves led to a reduction of the fungus development by up to 90%, independently of any cryptogein treatment and in the absence of apparent necrosis. These results indicate that the up-regulation of apoplastic RNase activity after inoculation could contribute to the control of fungal invasion in plants induced to SAR with cryptogein.

Shikimic Acid and Salicylic Acid Induced Protection on Growth Vigor, Seed Yield and Biochemical Aspects of Yielded Seeds of Vicia faba Plants Infected by Botrytis fabae

“…This suggestion was strongly supported by several investigators [43,44] who reported that RNase gene expression and activity often increase in response to pathogen attack. Moreover, Booker [45] reported that Ribonucleases (RNases) degrade RNA and exert a major influence on gene expression during development and in response to biotic and abiotic stresses.…”

Requirement of the Cytosolic Interaction between PATHOGENESIS-RELATED PROTEIN10 and LEUCINE-RICH REPEAT PROTEIN1 for Cell Death and Defense Signaling in Pepper

“…Notably, LRR1 potentiates the RNase activity of PR10. RNase activity is thought to be essential for the resistance response to microbial pathogens (Barna et al, 1989;Lusso and Kuc, 1995;Galiana et al, 1997;Shivakumar et al, 2000;Park et al, 2004). In this study, LRR1 is also shown to be a potential stimulator of PR10 phosphorylation, which could lead to the activation of defense and HR-like cell death.…”

Gene expression profiling and protection of Medicago truncatula against a fungal infection in response to an elicitor from green algae Ulva spp

“…In addition it was shown that UE treatment up-regulated other defence genes whose induction by marine algal elicitors was not previously reported, notably genes encoding cell wall proteins, calmodulin, ribonuclease, aquaporin and HSR203. Previous reports have indicated that these genes respond to elicitor treatments and/or pathogen attack (Oppermann, Taylor & Conkling 1994;Chappell et al 1997;Galiana et al 1997;Garcia-Muniz, Martinez-Izquierdo & Puigdomenech 1998;Ali et al 2003).…”