A novel elicitor identified from Magnaporthe oryzae triggers defense responses in tobacco and rice

Abstract

Our studies indicate a potential important elicitor candidate which can aid in the fight against a worldwide disease, rice blast. In this study, we report the purification, identification, characterization, and gene cloning of a novel hypersensitive response-inducing protein elicitor (MoHrip2) secreted from an important pathogenic fungus, Magnaporthe oryzae. The protein fraction was isolated from the culture filtrate of M. oryzae and identified by de novo sequencing. The elicitor-encoding gene mohrip2 was cloned following sequence comparison and PCR amplification. This 459-bp gene encodes a 152-residue polypeptide that contains an 18-residue signal peptide and exhibits a pI of 4.72 and an apparent molecular mass of 16 kDa. The hypothetical protein, MoHrip2, was expressed in Escherichia coli, and both the recombinant and the endogenous protein caused necrotic lesions in tobacco leaves. In addition to phenolic compound deposition and alkalization of the extracellular medium, MoHrip2 also induced hydrogen peroxide production and nitric oxide accumulation in tobacco cells. Moreover, rice seedlings treated with MoHrip2 exhibited pronounced resistance to M. oryzae compared with control seedlings.

Elicitor activity of algino-oligosaccharide and its potential application in protection of rice plant (Oryza salivaL.) againstMagnaporthe grisea

“…[28] Recently, a novel secreted protein elicitor from the rice pathogen M. oryzae was shown to reduce the leaf blast score by about 40%. [29] However, none of these elicitors is of oligosaccharide nature. To the best of our knowledge, this is the first study to apply algino-oligosaccharides in protection against rice blast disease.…”

Enhanced disease resistance and drought tolerance in transgenic rice plants overexpressing protein elicitors from Magnaporthe oryzae

“…MoHrip1 and MoHrip2 were isolated from the pathogenic fungus M . oryzae , and the gene sequences of the two elicitors were cloned [14,15]. In the present work, rice was successfully transformed with recombinant mohrip1 and mohrip2 independently.…”

“…Moreover, the exogenous application of these elicitors in rice seedlings induces the early events of the defense response in tobacco, such as reactive oxygen species (ROS) and enhanced resistance to the blast fungus M . o ryzae [14,15]. …”

Berberine induces resistance against tobacco mosaic virus in tobacco

“…The HR‐inducing activity of berberine was evaluated as previously reported . Briefly, berberine samples (1 mg mL −1 , 50 μL) were gently injected into the back of tobacco leaves using syringes without needles.…”

“…Systemic acquired resistance (SAR) is a highly desirable form of plant resistance against a broad spectrum of pathogens that has long‐lasting effects and results in less damage to crops . SAR activation by different inducers involves a hypersensitive reaction (HR), accumulation of H 2 O 2 , increase in defensive enzyme activity and increased expression of pathogenesis‐related (PR) proteins in plants . SAR can be triggered by exposing plants to biomacromolecules, such as glycoprotein and oligosaccharide, or to chemicals such as exogenous salicylic acid (SA), 2,6 ‐ dichlor ‐ isonicotinic acid (INA) and benzo(1,2,3)thiadiazole ‐ 7 ‐ carbothioic acid S‐ methyl ester (BTH) .…”