Purification and Characterization of a Novel Hypersensitive Response-Inducing Elicitor from Magnaporthe oryzae that Triggers Defense Response in Rice

Abstract

Background Magnaporthe oryzae, the rice blast fungus, might secrete certain proteins related to plant-fungal pathogen interactions.Methodology/Principal FindingsIn this study, we report the purification, characterization, and gene cloning of a novel hypersensitive response-inducing protein elicitor (MoHrip1) secreted by M. oryzae. The protein fraction was purified and identified by de novo sequencing, and the sequence matched the genomic sequence of a putative protein from M. oryzae strain 70-15 (GenBank accession No. XP_366602.1). The elicitor-encoding gene mohrip1 was isolated; it consisted of a 429 bp cDNA, which encodes a polypeptide of 142 amino acids with a molecular weight of 14.322 kDa and a pI of 4.53. The deduced protein, MoHrip1, was expressed in E. coli. And the expression protein collected from bacterium also forms necrotic lesions in tobacco. MoHrip1 could induce the early events of the defense response, including hydrogen peroxide production, callose deposition, and alkalization of the extracellular medium, in tobacco. Moreover, MoHrip1-treated rice seedlings possessed significantly enhanced systemic resistance to M. oryzae compared to the control seedlings. The real-time PCR results indicated that the expression of some pathogenesis-related genes and genes involved in signal transduction could also be induced by MoHrip1.Conclusion/SignificanceThe results demonstrate that MoHrip1 triggers defense responses in rice and could be used for controlling rice blast disease.

PeBL1, a Novel Protein Elicitor from Brevibacillus laterosporus Strain A60, Activates Defense Responses and Systemic Resistance in Nicotiana benthamiana

“…For example, harpins are multifunctional protein elicitors produced by Gram-negative plant-pathogenic bacteria (21). The fungal elicitors Hrip1, PevD1, and MoHrip1 from Verticillium dahliae, Alternaria tenuissima, and Magnaporthe oryzae, respectively, have been applied to plants to improve their pathogen resistance (22)(23)(24). However, a few reports have focused on elicitors that were isolated from biocontrol bacteria.…”

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

“…Samsun NN) and the rice seedling cultivar Nipponbare (Oryza sativa spp. japonica) used in this study were grown under the same condition described as former publication (Chen et al 2012). The method of tobacco cell suspensions establishment was also as same as described before (Chen et al 2012).…”

“…Crude protein was prepared according to a previously described ammonium sulfate precipitation method (Chen et al 2012). The concentrated fraction of crude protein was purified using the Ä KTA explorer 10 Protein Purification System (GE Healthcare, Piscataway, USA).…”

“…Some of these elicitors, such as Hrip1 (Kulye et al 2012), PaNie (Veit et al 2001), and MoHrip1 (Chen et al 2012), have been applied to plants to improve their pathogen resistance (Bent and Mackey 2007). These defense responses are often associated with HR and even localized programmed cell death (Hammond-Kosack and Parker 2003) and are involved in ion influx, NO production and ROS.…”

“…Rice blast fungus, Magnaporthe oryzae, is the most devastating pathogen of rice and causes substantial economic losses in epidemic years (Dean et al 2005). Some elicitors have been identified from M. oryzae, including two sphingolipid elicitors that have been shown to trigger phytoalexin accumulation and hypersensitive cell death in rice plants (Koga et al 1998), two glycoproteins that have been demonstrated to induce resistance responses in rice (Kanoh et al 1993;Schaffrath et al 1995), and two protein elicitors that have been demonstrated to activate certain early events and SAR (Systemic Acquired Resistance) in plants (Chen et al 2012;Qiu et al 2009). All of these elicitors enhanced the resistance level of the plants against the pathogen, suggesting a potential defense mechanism against rice blast.…”