Abstract
Ustilaginoidea virens is a ubiquitous plant pathogen that causes rice false smut disease, one of the most destructive diseases of rice (Oryza sativa L.) production. However, data concerning the effect of inoculation on disease development and the infection process of this pathogen are not comprehensive. In this study, the developmental processes of U. virens in rice panicles were characterized using an enhanced green fluorescent protein (EGFP) labelled strain. A mixture of hyphae and conidia of U. virens was used to inoculate rice panicles by leaf sheath injection during the booting stage of rice plants grown in a greenhouse. The panicles were assessed to determine the relationship between artificial inoculation and disease occurrence. Increasing volumes of inocula (0.2, 0.5, 1, and 2 ml of a mixture of hyphae-fragment and 2 × 106 conidia/ml suspension) caused more severe infections, and small differences were also observed for the different inoculation sites at the base, apex and mid-point of rice panicles. The optimum inoculation condition was 1–2 ml inoculum injected into the mid-point of rice panicles. Spikelet samples were collected as the disease progressed and observed by confocal laser scanning microscopy and scanning electron microscopy. The images collected showed that the primary site of U. virens colonization was at the base of the filaments with the inner spikelets becoming infected by hyphae at 24 h post inoculation (hpi). The accumulation of hyphae reached its highest level at 168 hpi, before the rice heading stage, as the infection extended upward from basal filaments to the anther apex, and then enclosed all the floral organs to produce a velvety smut ball.
Similar content being viewed by others
References
Ahonsi, M. O., & Adeoti, A. A. (2002). False smut on upland rice in eight rice producing locations of Edo State, Nigeria. Journal of Sustainable Agriculture, 20(3), 81–94.
Ashizawa, T., & Kataoka, Y. (2005). Detection of Ustilaginoidea virens in rice panicles before and after heading in the field using nested-PCR technique with species-specific primers. Japanese Journal of Phytopathology, 71(1), 16–19.
Ashizawa, T., Takahashi, M., Moriwaki, J., & Hirayae, K. (2010). Quantification of the rice false smut pathogen Ustilaginoidea virens from soil in Japan using real-time PCR. European Journal of Plant Pathology, 128(2), 221–232.
Ashizawa, T., Takahasi, M., Moriwaki, J., & Hirayae, K. (2011). A refined inoculation method to evaluate false smut resistance in rice. Journal of General Plant Pathology, 77(1), 10–16.
Ashizawa, T., Takahashi, M., Arai, M., & Arie, T. (2012). Rice false smut pathogen, Ustilaginoidea virens, invades through small gap at the apex of a rice spikelet before heading. Journal of General Plant Pathology, 78(4), 255–259.
Atia, M. M. M. (2004). Rice false smut (Ustilaginoidea virens) in Egypt. Journal of Plant Diseases and Protection, 111(1), 71–82.
Birch, P. R. J., Rehmany, A. P., Pritchard, L., Kamoun, S., & Beynon, J. L. (2006). Trafficking arms: oomycete effectors enter host plant cells. Trends in Microbiology, 14(1), 8–11.
Bischoff, J. F., Sullivan, R. F., Kjer, K. M., & White, J. F. (2004). Phylogenetic placement of the anamorphic tribe Ustilaginoideae (Hypocreales, Ascomycota). Mycologia, 96(5), 1088–1094.
Brooks, S. A., Anders, M. M., & Yeater, K. M. (2009). Effect of cultural management practices on the severity of false smut and kernel smut of rice. Plant Disease, 93(11), 1202–1208.
Brown, N. A., Urban, M., Van De Meene, A. M. L., & Hammond-Kosack, K. E. (2010). The infection biology of Fusarium graminearum:defining the pathways of spikelet to spikelet colonisation in wheat ears. Fungal Biology, 114(7), 555–571.
Cai, H. S., & Zhou, Y. L. (2009). Observation and detection of Ustilaginoidea virens in inoculated rice spikelets. Journal of Fungal Research, 7(3–4), 164–166 (in Chinese).
Dodds, P. N., Lawrence, G. J., Catanzariti, A. M., Ayliffe, M. A., & Ellis, J. G. (2004). The Melampsora lini AvrL567 avirulence genes are expressed in haustoria and their products are recognized inside plant cells. Plant Cell, 16(3), 755–768.
Fu, R. T., Ding, L., Zhu, J., Li, P., & Zheng, A. P. (2012). Morphological structure of propagules and electrophoretic karyotype analysis of false smut Villosiclava virens in rice. Journal of Microbiology, 50(2), 263–269.
Hashioka, Y. (1971). Rice disease in the world, VIII. Diseases due to Hypocreales, Ascomycetes (Fungal diseases, no.5). Riso, 20, 235–258.
Ikegami, H. (1962). Study on the false smut of rice. V. Seedling inoculation with the chlamydospores of the false smut fungus. Annals of the Phytopathological Society of Japan, 27, 16–23.
Kemen, E., Kemen, A. C., Rafiqi, M., Hempel, U., Mendgen, K., Hahn, M., et al. (2005). Identification of a protein from rust fungi transferred from haustoria into infected plant cells. Molecular Plant Microbe Interactions, 18(11), 1130–1139.
Koiso, Y., Natori, M., Iwasaki, S., Sato, S., Sonoda, R., Fujita, Y., et al. (1992). Ustiloxin: a phytotoxin and a mycotoxin from false smut balls on rice panicles. Tetrahedron Letters, 33(29), 4157–4160.
Ladhalakshmi, D., Laha, G. S., Singh, R., Karthikeyan, A., Mangrauthia, S. K., Sundaram, R. M., et al. (2012). Isolation and characterization of Ustilaginoidea virens and survey of false smut disease of rice in India. Phytoparasitica, 40(2), 171–176.
Lee, F. N., & Gunnell, P. S. (1992). False smut. In R. K. Webster & P. S. Gunnell (Eds.), Compendium of rice diseases (p. 28). St. Paul: American Phytopathological Society Press.
Miyazaki, S., Matsumoto, Y., Uchihara, T., & Morimoto, K. (2009). High-performance liquid chromatographic determination of ustiloxin A in forage rice silage. Journal of Veterinary Medical Science, 71(2), 239–241.
Pazoutova, S. (2001). The phylogeny and evolution of the genus Claviceps. Mycological Research, 105, 275–283.
Rush, M. C., Shahjahan, A. K. M., Jones, J. P., & Groth, D. E. (2000). Outbreak of false smut of rice in Louisiana. Plant Disease, 84(1), 100.
Scheffer, J., & Tudzynski, P. (2006). In vitro pathogenicity assay for the ergot fungus Claviceps purpurea. Mycological Research, 110, 465–470.
Schroud, P., & TeBeest, D. O. (2006). Germination and infection of rice roots by spores of Ustilaginoidea virens. Research Series - Arkansas Agricultural Experiment Station, 540, 143–151.
Sella, L., Gazzetti, K., Faoro, F., Odorizzi, S., D’Ovidio, R., Schafer, W., et al. (2013). A Fusarium graminearum xylanase expressed during wheat infection is a necrotizing factor but is not essential for virulence. Plant Physiology and Biochemistry, 64, 1–10.
Shan, T. J., Sun, W. B., Liu, H., Gao, S., Lu, S. Q., & Wang, M. G. (2012). Determination and analysis of Ustiloxins A and B by LC-ESI-MS and HPLC in false smut balls of rice. International Journal of Molecular Sciences, 13(9), 11275–11287.
Sonoda, R., Ashizawa, T., Koga, H., & Saito, H. (1997). Estimation of infection period of rice false smut in the field. [Ustilaginoidea virens]. Annual Report of the Society of Plant Protection of North Japan, 48, 39–42.
Tanaka, E., & Tanaka, C. (2008). Phylogenetic study of Clavicipitaceous fungi using acetaldehyde dehydrogenase gene sequences. Mycoscience, 49, 115–125.
Tanaka, E., Ashizawa, T., Sonoda, R., & Tanaka, C. (2008). Villosiclava virens gen. nov., com. nov., teleomorph of Ustilaginoidea virens, the causal agent of rice false smut. Mycotaxon, 106, 491–501.
Tanaka, E., Kumagawa, T., Tanaka, C., & Koga, H. (2011). Simple transformation of the rice false smut fungus Villosiclava virens by electroporation of intact conidia. Mycoscience, 52(5), 344–348.
Tang, Y. X., Jin, J., Hu, D. W., Yong, M. L., Xu, Y., & He, L. P. (2013). Elucidation of the infection process of Ustilaginoidea virens (teleomorph: Villosiclava virens) in rice spikelets. Plant Pathology, 62(1), 1–8.
Tsuda, M., Sasahara, M., Ohara, T., & Kato, S. (2006). Optimal application timing of simeconazole granules for control of rice kernel smut and false smut. Journal of General Plant Pathology, 72(5), 301–304.
White, J. F., Sullivan, R., Moy, M., Patel, R., & Duncan, R. (2000). An overview of problems in the classification of plant-parasitic Clavicipitaceae. Studies in Mycology, 45, 95–105.
Yang, X. J., Wang, S. T., Ruan, H. C., Shi, N. N., Gan, L., & Chen, F. R. (2011). Artificial inoculation techniques of rice false smut in greenhouse. Acta Phytophylacica Sinica, 38(5), 395–400 (in Chinese).
Zhang, J. C., Chen, Z. Y., Zhang, B. X., Liu, Y. F., & Lu, F. (2004). Inoculation techniques used for inducing rice false smut efficiently. Acta Phytopathologica Sinica, 34(5), 463–467 (in Chinese).
Zhang, Z., Du, X. F., Chai, R. Y., Mao, X. Q., Qiu, H. P., Wang, Y. L., et al. (2006). Agrobacterium tumefaciens-mediated transformation of the pathogen of Ustilaginoidea virens. Zhongguo Shuidao Kexue, 20(4), 440–442 (in Chinese).
Zhou, Y. L., Pan, Y. J., Xie, X. W., Zhu, L. H., Wang, S., & Li, Z. K. (2008). Genetic diversity of rice false smut fungus, Ustilaginoidea virens and its pronounced differentiation of populations in north China. Journal of Phytopathology, 156(9), 559–564.
Acknowledgments
This research was supported by the Special Fund for Agro-scientific Research in the Public Interest of China (No. 200903039-8), the Program for Changjiang Scholars and Innovative Research Team in University “Researches on Controlling of Important Crop Diseases” (No. IRT1042) and the Ph.D. graduate academic new artist of the Ministry of Education grant (2012YJ012). The authors would like to thank Prof. Dongwei Hu for his help in collecting samples, as well as Prof. Xinqiu Tan, Prof. Chaoxi Luo, Prof. Xiaozhou Liu, and Prof. Wenxian Sun for their excellent technical assistance.
Author information
Authors and Affiliations
Corresponding authors
Rights and permissions
About this article
Cite this article
Hu, M., Luo, L., Wang, S. et al. Infection processes of Ustilaginoidea virens during artificial inoculation of rice panicles. Eur J Plant Pathol 139, 67–77 (2014). https://doi.org/10.1007/s10658-013-0364-7
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10658-013-0364-7