| Autor: |
Roy S; CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, Telangana State, India 500007., Mittal P; MRC Human Genetics Unit, University of Edinburgh, Crewe Road South, Edinburgh, UK, EH4 2XU., Tayi L; Center for Plant Molecular Biology, Osmania University, Tarnaka, Hyderabad, Telangana State, India 500007., Bondada S; CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, Telangana State, India 500007., Ray MK; CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, Telangana State, India 500007., Patel HK; CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, Telangana State, India 500007., Sonti RV; Indian Institute of Science Education and Research, Tirupati, Andhra Pradesh, India 517507. |
| Abstrakt: |
Exoribonuclease R (RNase R) is a 3' hydrolytic exoribonuclease that can degrade structured RNA. Mutation in RNase R affects virulence of certain human pathogenic bacteria. The aim of this study was to determine whether RNase R is necessary for virulence of the phytopathogen that causes bacterial blight in rice, Xanthomonas oryzae pv. oryzae (Xoo). In silico analysis has indicated that RNase R is highly conserved among various xanthomonads. Amino acid sequence alignment of Xoo RNase R with RNase R from various taxa indicated that Xoo RNase R clustered with RNase R of order Xanthomonadales. To study its role in virulence, we generated a gene disruption mutant of Xoo RNase R. The Xoo rnr - mutant is moderately virulence deficient, and the complementing strain ( rnr - /pHM1:: rnr ) rescued the virulence deficiency of the mutant. We investigated swimming and swarming motilities in both nutrient-deficient minimal media and nutrient-optimal media. We observed that RNase R mutation has adversely affected the swimming and swarming motilities of Xoo in optimal media. However, in nutrient-deficient media only swimming motility was noticeably affected. Growth curves in optimal media at suboptimal temperature (15°C cold stress) indicate that the Xoo rnr - mutant grows more slowly than the Xoo wild type and complementing strain ( rnr - /pHM1:: rnr ). Given these findings, we report for the first time that RNase R function is necessary for complete virulence of Xoo in rice. It is also important for motility of Xoo in media and for growth of Xoo at suboptimal temperature. |
