Abstract
Pantoea agglomerans pvs. gypsophilae and betae are related gall-forming bacteria. While P. agglomerans pv. beta initiates gall formation on both beet and gypsophila, the gypsophila pathovar causes gall formation only on gypsophila. PthG is a type III effector determining host range of these pathogens, initiating the hypersensitivity response in beet, but is a virulence factor in gypsophila. The role of PthG and its mode of action in pathogenicity remain unclear. Transgenic Nicotiana tabacum plants expressing pthG were created. PthG over-expression was often lethal, and surviving pthG-bearing lines showed morphological and developmental abnormalities such as leaf deformation and abnormal vascular branching, dwarf stature, loss of apical dominance, seedling apical meristem loss, rapid germination, reduced fertility, plants which cease growth for several weeks later producing a new lateral shoot, and loss of endophyte resistance (bearing unusual saprophyte populations). Some transformants required light for seed germination and showed rapid seedling greening. In in vitro assays PthG expression modified responses to auxin and cytokinin, inhibiting root and shoot production but not callus formation. In vitro differentiation responses to light were modified by PthG expression. This effector may interfere in the plant auxin signalling pathways resulting in higher observed auxin and ethylene levels, and subsequent blockage of root and shoot development. Apparently PthG tunes the host response to high hormone levels, changing the developmental response. Since shoot and root development are delayed, we hypothesize that callus/gall formation is supported by this activity. However, interference by PthG with hormone and light signalling does not explain all the responses observed in pthG-bearing lines.
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Abbreviations
- BA:
-
Benzyl adenine
- CT:
-
Cycle threshold
- GA3 :
-
Gibberellic acid
- HR:
-
Hypersensitive response
- hrc :
-
hrp conserved
- hrp :
-
Hypersensitive response and pathogenicity
- IAA:
-
Indole-3-acetic acid
- LB:
-
Luria Broth
- MS:
-
Murashige and Skoog (1962) medium
- NAA:
-
1-naphthaleneacetic acid
- Pab :
-
P. agglomerans pv. betae
- Pag :
-
P. agglomerans pv. gypsophilae
- PDA:
-
Potato dextrose agar
- qRT-PCR:
-
Quantitative reverse transcriptase (Real Time) PCR
- STS:
-
Silver thiosulphate
- T3SS:
-
Type III secretion system
- TC:
-
Transgenic (“empty vector”) control
References
Achard, P., Vriezen, W. H., Van Der Straeten, D., & Harberd, N. P. (2003). Ethylene regulates Arabidopsis development via the modulation of DELLA protein growth repressor function. The Plant Cell, 15, 2816–2825.
Aloni, R., Wolf, A., Feigenbaum, P., Avni, A., & Klee, H. J. (1998). The never ripe mutant provides evidence that tumor induced ethylene controls the morphogenesis of Agrobacterium tumefaciens-induced crown galls on tomato stems. Plant Physiology, 117, 841–849.
Aloni, R., Langhans, M., Aloni, E., Dreieicher, E., & Ullrich, C. I. (2005). Root-synthesized cytokinin in Arabidopsis is distributed in the shoot by the transpiration stream. Journal of Experimental Botany, 56, 1535–1544.
Barash, I., & Manulis-Sasson, S. (2007). Virulence mechanisms and host specificity of gall-forming Pantoea agglomerans. Trends in Microbiology, 15, 538–545.
Barash, I., & Manulis-Sasson, S. (2009). Recent evolution of bacterial pathogens: the gall-forming Pantoea agglomerans case. Annual Review of Phytopathology, 47, 133–152.
Benjamins, R., & Scheres, B. (2008). Auxin: the looping star in plant development. Annual Review of Plant Biology, 59, 443–465.
Beno-Moualem, D., Gusev, L., Dvir, O., Pesis, E., Meir, S., & Lichter, A. (2004). The effects of ethylene, methyl jasmonate and 1-MCP on abscission of cherry tomatoes from the bunch and expression of endo-1, 4-β-glucanases. Plant Science, 167, 499–507.
Brunings, A. M., & Gabriel, D. W. (2003). Pathogen profile Xanthomonas citri: breaking the surface. Molecular Plant Pathology, 4, 141–157.
Büttner, D., & Bonas, U. (2006). Who comes first? How plant pathogenic bacteria orchestrate type III secretion. Current Opinion in Microbiology, 9, 193–200.
Campanoni, P., Blasius, B., & Nick, P. (2003). Auxin transport synchronizes the pattern of cell division in a tobacco cell line. Plant Physiology, 133, 1251–1260.
Casanova, E., Zuker, A., Trillas, M. I., Moysset, L., & Vainstein, A. (2003). The rolC gene in carnation exhibits cytokinin- and auxin-like activities. Scientia Horticulturae, 97, 321–331.
Castellano, J. M., & Vioque, B. (2002). Characterisation of the ACC oxidase activity in transgenic auxin overproducing tomato during ripening. Plant Growth Regulators, 38, 203–208.
Chalupowicz, L., Barash, I., Schwartz, M., Aloni, R., & Manulis, S. (2006). Comparative anatomy of gall development on Gypsophila paniculata induced by bacteria with different mechanisms of pathogenicity. Planta, 224, 429–437.
Chen, Z., Agnew, J. L., Cohen, J. D., He, P., Shan, L., Sheen, J., et al. (2007). Pseudomonas syringae type III effector AvrRpt2 alters Arabidopsis thaliana auxin physiology. Proceedings of the National Academy of Sciences of the United States of America, 104, 20131–20136.
de Torres-Zabala, M., Truman, W., Bennett, M. H., Lafforgue, G., Mansfield, J. W., Rodriguez Egea, P., et al. (2007). Pseudomonas syringae pv. tomato hijacks the Arabidopsis abscisic acid signalling pathway to cause disease. The EMBO Journal, 26, 1434–1443.
Ezra, D., Barash, I., Valinsky, L., & Manulis, S. (2000). The dual function in virulence and host range restriction of a gene isolated from pPATHEhg plasmid of Erwinia herbicola pv. gypsophilae. Molecular Plant-Microbe Interactions, 13, 693–698.
Ezra, D., Barash, I., Weinthal, D. M., Gaba, V., & Manulis, S. (2004). pthG from Pantoea agglomerans pv. gypsophilae encodes an avirulence effector that determines incompatibility in multiple beet species. Molecular Plant Pathology, 5, 105–113.
Gallavotti, A., Yang, Y., Schmidt, R. J., & Jackson, D. (2008). The relationship between auxin transport and maize branching. Plant Physiology, 147, 1913–1923.
Goto, M., Takahashi, T., & Okajima, T. (1980). A comparative study of Erwinia melletiae and Erwinia herbicola. Annals Phytopathological Society of Japan, 46, 185–192.
Hardtke, C. S., & Berleth, T. (1998). The Arabidopsis gene MONOPTEROS encodes a transcription factor mediating embryo axis formation and vascular development. The EMBO Journal, 17, 1405–1411.
Harrison, S. J., Mott, E. K., Parsley, K., Aspinall, S., Gray, J. C., & Cottage, A. (2006). A rapid and robust method of identifying transformed Arabidopsis thaliana seedlings following floral dip transformation. Plant Methods, 2, 19.
Hellens, R. P., Edwards, E. A., Leyland, N. R., Bean, S., & Mullineaux, P. M. (2000). pGreen: a versatile and flexible binary Ti vector for Agrobacterium-mediated plant transformation. Plant Molecular Biology, 42, 819–832.
Hood, E. E. (1993). New Agrobacterium helper plasmids for gene transfer to plants. Transgenic Research, 2, 208–218.
Hoshi, A., Oshimaa, K., Kakizawa, S., Ishii, Y., Ozeki, J., Hashimoto, M., et al. (2009). A unique virulence factor for proliferation and dwarfism in plants identified from a phytopathogenic bacterium. Proceedings of the National Academy of Sciences of the United States of America, 106, 6416–6421.
Inoue, T., Higuchi, M., Hashimoto, Y., Seki, M., Kobayashi, M., Kato, T., et al. (2001). Identification of CRE1 as a cytokinin receptor from Arabidopsis. Nature, 409, 1060–1063.
Korber, H., Strizhov, N., Staiger, D., Feldwisch, J., Olsson, O., Sandberg, G., et al. (1991). T-DNA gene 5 of Agrobacterium modulates auxin response by autoregulated synthesis of a growth hormone antagonist in plants. EMBO Journal, 10, 3983–3991.
Long, J. A., Moan, E. I., Medford, J. I., & Barton, M. K. (1996). A member of the KNOTTED class of homeodomain proteins encoded by the SHOOTMERISTEMLESS gene of Arabidopsis. Nature, 379, 66–69.
Maldonado-Mendoza, I. E., Lopez-Meyer, M., & Nessler, C. L. (1996). Transformation of tobacco and carrot using Agrobacterium tumefaciens and expression of the b-glucuronidase (GUS) reporter gene. In R. N. Trigano & D. J. Gray (Eds.), Plant tissue culture concepts and laboratory exercises (pp. 261–274). Boca Raton: CRC.
Morris, R. O. (1986). Genes specifying auxin and cytokinin biosynthesis in phytopathogens. Annual Review Plant Physiology, 37, 509–538.
Murashige, T., & Skoog, F. (1962). A revised medium for rapid growth and bioassays with tobacco tissue cultures. Physiologia Plantarum, 15, 473–497.
Navarro, L., Dunoyer, P., Jay, F., Arnold, B., Dharmasiri, N., Estelle, M., et al. (2006). A plant miRNA contributes to antibacterial resistance by repressing auxin signaling. Science, 312, 436–439.
Nester, E. W., Gordon, M. P., Amasino, R. M., & Yanofsky, M. F. (1984). Crown gall: a molecular and physiological analysis. Annual Review of Plant Physiology, 35, 387–413.
O’Donnell, P. J., Schmelz, E. A., Moussatche, P., Lund, S. T., Jones, J. B., & Klee, H. J. (2003). Susceptible to intolerance—a range of hormonal actions in a susceptible Arabidopsis pathogen response. The Plant Journal, 33, 245–257.
Ongaro, V., Bainbridge, K., Williamson, L., & Leyser, O. (2008). Interactions between axillary branches of Arabidopsis. Molecular Plant, 1, 388–400.
Perl, A., Aviv, D., & Galun, E. (1988). Ethylene and in vitro culture of potato: suppression of ethylene generation vastly improves protoplast yield, plating efficiency and transient expression of an alien gene. Plant Cell Reports, 7, 403–406.
Remans, R., Spaepen, S., & Vanderleyden, J. (2006). Auxin signaling in plant defense. Science, 313, 171.
Robert-Seilaniantz, A., Navarro, L., Bari, R., & Jones, J. D. (2007). Pathological hormone imbalances. Current Opinion in Plant Biology, 10, 372–379.
Romano, C. P., Cooper, M. L., & Klee, H. J. (1993). Uncoupling auxin and ethylene effects in transgenic tobacco and Arabidopsis plants. The Plant Cell, 5, 181–189.
Rotem, J. (1994). The genus Alternaria: Biology, epidemiology, and pathogenicity. St Paul: APS.
Sagee, O., Riov, J., & Goren, R. (1990). Ethylene-enhanced catabolism of [14C]indole-3-acetic acid to indole-3-carboxylic acid in citrus leaf tissues. Plant Physiology, 91, 54–60.
Salmon, J., Ramos, J., & Callis, J. (2008). Degradation of the auxin response factor ARF1. The Plant Journal, 54, 118–128.
Schmelz, E. A., Engelberth, J., Alborn, H. T., O’Donnell, P., Sammons, M., Toshima, H., et al. (2003). Simultaneous analysis of phytohormones, phytotoxins, and volatile organic compounds in plants. Proceedings of the National Academy of Science, 100, 10552–10557.
Sisto, A., Cipriani, M. G., & Morea, M. (2004). Knot formation caused by Pseudomonas syringae subsp. savastanoi on olive plants is hrp-dependent. Phytopathology, 94, 484–489.
Spoel, S. H., Johnson, J. S., & Dong, X. (2007). Regulation of tradeoffs between plant defenses against pathogens with different lifestyles. Proceedings of the National Academy of Sciences of the United States of America, 104, 18842–18847.
Vandeputte, O., Oden, S., Mol, A., Vereecke, D., Goethals, K., El Jaziri, M., et al. (2005). Biosynthesis of auxin by the Gram-positive phytopathogen Rhodococcus fascians is controlled by compounds specific to infected plant tissues. Applied and Environmental Microbiology, 71, 1169–1177.
Vasanthakumar, A., & McManus, P. C. (2004). Indole-3-acetic acid-producing bacteria are associated with cranberry stem gall. Phytopathology, 94, 1164–1171.
Vidaurre, D. P., Ploense, S., Krogan, N. T., & Berleth, T. (2007). AMP1 and MP antagonistically regulate embryo and meristem development in Arabidopsis. Development, 134, 2561–2567.
Vogel, G. (2006). Auxin begins to give up its secrets. Science, 313, 1230–1231.
Walters, D. R., & McRoberts, N. (2006). Plants and biotrophs: a pivotal role for cytokinins? Trends in Plant Science, 11, 581–586.
Weinthal, D. M., Barash, I., Panijel, M., Valinsky, L., Gaba, V., & Manulis-Sasson, S. (2007). Distribution and replication of the pathogenicity plasmid pPATH in diverse populations of the gall-forming Pantoea agglomerans. Annals of Environmental Microbiology, 73, 7552–7561.
Yang, T. F., Gonzalez-Carraza, Z. H., Maunders, M. J., & Roberts, J. A. (2008). Ethylene and the regulation of senescence process in transgenic Nicotiana sylvestris plants. Annals of Botany, 101, 301–310.
Zambryski, P. C. (1992). Chronicles from the Agrobacterium-plant cell DNA transfer story. Annual Review of Plant Physiology, 43, 465–490.
Zeier, J. R., Pink, B., Mueller, M. J., & Berger, S. (2004). Light conditions influence specific defense responses in incompatible plant–pathogen interactions: uncoupling systemic resistance from salicylic acid and PR-1 accumulation. Planta, 219, 673–683.
Zupan, J., Muth, T. R., Draper, O., & Zambryski, P. (2000). The transfer of DNA of Agrobacterium tumefaciens into plants: a feast of fundamental insights. Plant Journal, 23, 11–28.
Acknowledgements
Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel, No. 517/09. The authors thank Dr. Amnon Lichter for help with qRT-PCR, Daniel Chalupowicz for help with ethylene measurements, and Prof. H. Fromm for critical comments on the ms.
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Supplementary Figure 1
pthG-bearing cv. Samsun NN lines can carry a greater endophyte microbial population. (A) Transgenic empty vector control and (B) pthG line 44733 in tissue culture were sampled, disinfected and incubated on PDA medium at 25°C for 5 days. (DOCX 1159 kb)
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Weinthal, D.M., Yablonski, S., Singer, S. et al. The type III effector PthG of Pantoea agglomerans pv. gypsophilae modifies host plant responses to auxin, cytokinin and light. Eur J Plant Pathol 128, 289–302 (2010). https://doi.org/10.1007/s10658-010-9666-1
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DOI: https://doi.org/10.1007/s10658-010-9666-1