Fig. 1. Virulence phenotypes of PXO99A (WT) and RR mutant strains. (A) Lesion lengths caused by PXO99A (WT, black), RR mutant (white), and the complementary (gray) strains on Dongjin rice leaves at 14 days after infection (DAI). Rice leaves were infected with 107 cfu/ml of bacterial suspension by the scissor clipping method. Bars are mean ± SD (n = 20). * or ** indicate that the lesion length of each mutant was significantly different from that of PXO99A by Duncan’s test (P < 0.05). (B) Bacterial population at 0 (white) and 14 (gray) DAI. Immediately after infection (0 DAI) and at 14 DAI, 1-cm2 and 25-cm2 samples from the infected site of three leaves were used to extract the bacteria population at 0 and 14 dpi, respectively. Bars are mean ± SD (n = 3). * and ** indicate that the population of mutants was significantly smaller than that of PXO99A by Duncan’s test (P < 0.05). C) All experiments were repeated three times with high consistency, and the results from one experiment are shown.
Table 1. Sixty-two candidate RR genes in the PXO99A genome
Table 1. Continued
References
- Buelow, D. R. and Raivio, T. L. 2010. Three (and more) component regulatory systems - auxiliary regulators of bacterial histidine kinases. Mol. Microbiol. 75:547-566. https://doi.org/10.1111/j.1365-2958.2009.06982.x
- Burdman, S., Shen, Y., Lee, S. W., Xue, Q. and Ronald, P. 2004. RaxH/RaxR: A two-component regulatory system in Xanthomonas oryzae pv. oryzae required for AvrXa21 activity. Mol. Plant-Microbe Interact. 17:602-612. https://doi.org/10.1094/MPMI.2004.17.6.602
- Guo, Y., Figueiredo, F., Jones, J. and Wang, N. 2011. HrpG and HrpX play global roles in coordinating different virulence traits of Xanthomonas axonopodis pv. citri. Mol. Plant-Microbe Interact. 24:649-661. https://doi.org/10.1094/MPMI-09-10-0209
- He, Y. W., Boon, C., Zhou, L. and Zhang, L. H. 2009. Coregulation of Xanthomonas campestris virulence by quorum sensing and a novel two-component regulatory system RavS/RavR. Mol. Microbiol. 71:1464-1476. https://doi.org/10.1111/j.1365-2958.2009.06617.x
- He, Y. W., Wu, J., Cha, J. S. and Zhang, L. H. 2010. Rice bacterial blight pathogen Xanthomonas oryzae pv. oryzae produces multiple DSF-family signals in regulation of virulence factor production. BMC Microbiol. 10:187. https://doi.org/10.1186/1471-2180-10-187
-
Ikawa, Y., Furutani, A., Ochiai, H. and Tsuge, S. 2014. StoS, a hybrid histidine kinase sensor of Xanthomonas oryzae pv. oryzae, is activated by sensing low
$O_{2}$ concentration and is involved in stress tolerance and virulence. Mol. Plant-Microbe Interact. 27:537-545. https://doi.org/10.1094/MPMI-09-13-0263-R - Jeong, K. S., Lee, S. E., Han, J. W., Yang, S. U., Lee, B. M., Noh, T. H. and Cha, J. S. 2008. Virulence reduction and differing regulation of virulence genes in rpf mutants of Xanthomonas oryzae pv. oryzae. Plant Pathol J. 24:143-151. https://doi.org/10.5423/PPJ.2008.24.2.143
- Kauffman, H. E., Reddy, A. P. K., Hsieh, S. P. Y. and Merca, S. D. 1973. An improved technique for evaluating resistance of rice varieties to Xanthomonas oryzae. Plant Dis. Rep. 57:537-541.
- Lee, S. W. and Ronald, P. C. 2007. Marker-exchange mutagenesis and complementation strategies for the Gram-negative bacteria Xanthomonas oryzae pv. oryzae. Methods Mol. Biol. 354:11-18. https://doi.org/10.1385/1-59259-966-4:11
- Lee, S.-W., Jeong, K.-S., Han, S.-W., Lee, S.-E., Phee, B.-K., Hahn, T.-R. and Ronald, P. 2008. The Xanthomonas oryzae pv. oryzae PhoPQ two-component system is required for AvrXA21 activity, hrpG expression, and virulence. J. Bacteriol. 190:2183-2197. https://doi.org/10.1128/JB.01406-07
- Nguyen, M. P., Yoon, J. M., Cho, M. H. and Lee, S. W. 2015. Prokaryotic 2-component systems and the OmpR/PhoB superfamily. Can. J. Microbiol. 61:799-810. https://doi.org/10.1139/cjm-2015-0345
- Nguyen, M. P., Park, J., Cho, M. H. and Lee, S. W. 2016. Role of DetR in defence is critical for virulence of Xanthomonas oryzae pv. oryzae. Mol. Plant Pathol. 17:601-613. https://doi.org/10.1111/mpp.12305
- Pandey, S. S., Patnana, P. K., Lomada, S. K., Tomar, A. and Chatterjee, S. 2016. Co-regulation of iron metabolism and virulence associated functions by iron and XibR, a novel iron binding transcription factor, in the plant pathogen Xanthomonas. PLoS Pathog. 12:e1006019. https://doi.org/10.1371/journal.ppat.1006019
- Sahebi, M., Taheri, E. and Tarighi, S. 2015. CitB is required for full virulence of Xanthomonas oryzae pv. oryzae. World J. Microbiol. Biotechnol. 31:1619-1627. https://doi.org/10.1007/s11274-015-1914-2
- Stock, A. M., Robinson, V. L. and Goudreau, P. N. 2000. Twocomponent signal transduction. Annu. Rev. Biochem. 69:183-215. https://doi.org/10.1146/annurev.biochem.69.1.183
- Subramoni, S., Pandey, A., Vishnu Priya, M. R., Patel, H. K. and Sonti, R. V. 2012. The ColRS system of Xanthomonas oryzae pv. oryzae is required for virulence and growth in ironlimiting conditions. Mol. Plant Pathol. 13:690-703. https://doi.org/10.1111/j.1364-3703.2011.00777.x
- Tamir-Ariel, D., Rosenberg, T. and Burdman, S. 2011. The Xanthomonas campestris pv. vesicatoria citH gene is expressed early in the infection process of tomato and is positively regulated by the TctDE two-component regulatory system. Mol. Plant Pathol. 12:57-71. https://doi.org/10.1111/j.1364-3703.2010.00652.x
- Tao, J. and He, C. 2010. Response regulator, VemR, positively regulates the virulence and adaptation of Xanthomonas campestris pv. campestris. FEMS Microbiol. Lett. 304:20-28. https://doi.org/10.1111/j.1574-6968.2009.01892.x
- Tsuge, S., Nakayama, T., Terashima, S., Ochiai, H., Furutani, A., Oku, T., Tsuno, K., Kubo, Y. and Kaku, H. 2006. Gene involved in transcriptional activation of the hrp regulatory gene hrpG in Xanthomonas oryzae pv. oryzae. J. Bacteriol. 188:4158-4162. https://doi.org/10.1128/JB.00006-06
- Wengelnik, K., Van den Ackerveken, G. and Bonas, U. 1996. HrpG, a key hrp regulatory protein of Xanthomonas campestris pv. vesicatoria is homologous to two-component response regulators. Mol. Plant-Microbe Interact. 9:704-712. https://doi.org/10.1094/MPMI-9-0704
- Yang, F., Tian, F., Sun, L., Chen, H., Wu, M., Yang, C. H. and He, C. 2012. A novel two-component system PdeK/PdeR regulates c-di-GMP turnover and virulence of Xanthomonas oryzae pv. oryzae. Mol. Plant-Microbe Interact. 25:1361-1369. https://doi.org/10.1094/MPMI-01-12-0014-R
- Zheng, D., Yao, X., Duan, M., Luo, Y., Liu, B., Qi, P., Sun, M. and Ruan, L. 2016. Two overlapping two-component systems in Xanthomonas oryzae pv. oryzae contribute to full fitness in rice by regulating virulence factors expression. Sci. Rep. 6:22768. https://doi.org/10.1038/srep22768