The rice pathogen-related protein 10 (JIOsPR10) is induced by abiotic and biotic stresses and exhibits ribonuclease activity

Abstract

We previously reported that rice blast fungus or jasmonic acid induced the expression of rice pathogenesis-related class 10 (JIOsPR10) proteins (Kim et al. 2003, 2004). However, no further studies have been carried out to examine the expression, localization, and enzymatic activity of this protein in either developmental tissues or in tissues under abiotic stress conditions. In this study, rice JIOsPR10 was examined by Western blot analysis, immunolocalization, and biochemical assays. Western blots revealed that the JIOsPR10 protein was expressed in developmental tissues, including in flower and root. The protein was also expressed under abiotic stresses, such as occurs during senescence and wounding. Using immunohistochemical techniques, we determined that expression of JIOsPR10 was localized to the palea of flower, in the exodermis, and inner part of the endodermis of the root. In senescencing tissues of leaf and coleoptiles, its expression was localized in vascular bundles. The RNase activity using JIOsPR10 recombinant protein was determined and abolished after treatment with DTT in a native in-gel assay. To test this, we created JIOsPR10 mutant proteins containing serine substitutions of amino acids C81S, C83S, or both and examined their RNase activities. The activity of the C83S mutant was decreased in the agarose gel assay compared to the wild type. Taken together, we hypothesize that the JIOsPR10 protein possesses RNase activity that is sensitive to DTT, suggesting the importance of the disulfide bonding between cysteine residues and that it might play a role in constitutive self-defense mechanisms in plants against biotic and abiotic stresses.

Proteomics to identify pathogenesis-related proteins in rice roots under water deficit

“…JIOsPR10 was found to possess ribonuclease activity, but did not exhibit direct antifungal activity. The disulfide bonding between cysteine residues of the protein may play a role in constitutive self-defense mechanisms in plants against biotic and abiotic stresses (Kim et al 2008).…”

“…4). Taken together, we strongly suggest that these three PR proteins may play roles in root development under water deficit other than disease resistance response (Kim et al 2001(Kim et al , 2008Hashimoto et al 2004). Concerning the induction mechanisms of PR proteins expression, especially in relation to the crosstalk between various biotic and abiotic stresses, there were only a few reports (Kim et al 2008).…”

“…RSOsPR10 exhibited a significant increase in Nipponbare root after 15 h air-drying treatment, and its transcription was strongly up-regulated within 3 h (Hashimoto et al 2004). JIOsPR10 was rapidly induced by air-dried treatment in the stem, but not in the leaves (Kim et al 2008), while its expression change in rice root was not examined. In this case, PR-1a (spot 1) was up-regulated in IR64 and downregulated in Azucena, while both RSOsPR10 (spot 9) and JIOsPR10 (spot 5) proteins were induced more strongly in IR64 than in Azucena by water deficit at protein level (Table 3, Fig.…”

“…The gene RSOsPR10 was rapidly induced almost exclusively in roots (named root specific rice PR10) by salt, desiccation and jasmonic acid (JA) (Hashimoto et al 2004). JIOsPR10 belongs to a different type of PR10 protein, which was also shown to be induced by JA and SA at the mRNA level , and up-regulated by some abiotic stresses at protein level (Kim et al 2008). Immunohistochemical techniques revealed that JIOsPR10 was localized to the palea of flower, in the exodermis and inner part of the endodermis of the root.…”

Gene Expression Profiling in Rice Infected with Rice Blast Fungus using SAGE

“…The tags for PR-10 ( Kim et al, 2003;McGee et al, 2001;Tanaka et al, 2003) were detected a total of three times, suggesting that the protein seems to make a significant contribution as a biotic stress defense system. Recently, it was reported that the JIOsPR10 protein which is one of the PR-10 family possesses RNase activity that is dependent on sensitive to DTT, suggesting the importance of the disulfide bonding between cysteine residues (Kim et al, 2008a). In addition, expression level using Western blot, immunohistochemical, and its promoter analysis of PBZ1 protein (PR-10 family) is tightly associated with plant cell death tissues, suggesting that PBZ1 could serve as a cell death marker protein as well as defense protein in rice (Kim et al, 2008b).…”