Studies on the colonization of axenically grown tomato plants by a GFP-tagged strain of Clavibacter michiganensis subsp. michiganensis
Vieira Lelis, F.M. ; Czajkowski, R.L. ; Souza, R.M. de; Ribeiro, D.H. ; Wolf, J.M. van der - \ 2014
European Journal of Plant Pathology 139 (2014)1. - ISSN 0929-1873 - p. 53 - 66.
corynebacterium-michiganense - phytopathogenic bacterium - xylem sap - virulence - pathogens - tissue - seed - transmission - transplants - resistance
In this study, colonization and disease development of axenically-grown tomato plants by Clavibacter michiganensis subsp. michiganensis (Cmm), the causative agent of bacterial wilt and canker, was investigated. For this, a spontaneous rifampicin resistant strain of Cmm was tagged with a marker that expressed a green fluorescent protein (GFP) in a stable way and which possessed a similar virulence to the parental strain. In vitro plants were drop-inoculated at the stem base and the population dynamics was determined by dilution pour-plating in a selective medium. At 3 h after inoculation, Cmm was already present in low densities in roots, stems and leaves. At 16 dpi, Cmm was found throughout the entire plant in high densities of ca. 1010 cfu g-1. Symptoms developed in the in vitro plants typical for Cmm, such as canker, wilting and growth reduction. The presence of Cmm in vascular and parenchymatic tissue of in vitro tomato plants was confirmed by epifluorescence stereo- and confocal laser scanning microscopy. This study showed that in vitro tomato plants can be effectively used for detailed studies on interactions between Cmm and its host, in particular if a GFP-tagged strain of the pathogen is used
Screening for new sources of resistance to Clavibacter michiganensis subsp. michiganensis (Cmm) in tomato
Sen, Y. ; Zhu, F. ; Vandenbroucke, H. ; Wolf, J.M. van der; Visser, R.G.F. ; Heusden, A.W. van - \ 2013
Euphytica 190 (2013)2. - ISSN 0014-2336 - p. 309 - 317.
bacterial canker - corynebacterium-michiganense - lycopersicon-esculentum - ssp michiganensis - seeds - pcr - quantification - crosses
Bacterial canker of tomato, caused by Clavibacter michiganensis subsp. michiganensis (Cmm), is considered the most serious bacterial threat, resulting in high damages in production areas. Worldwide, Cmm is subjected to quarantine regulations.There is no cultivar in market containing Cmm resistance genes. This project aimed to screen tomatoes or wild relatives of tomato for resistance to Cmm, to be used for starting breeding programs. We have screened 24 different wild accessions of tomato and found several new tolerant sources: Solanum pimpinellifolium GI.1554, S. parviflorum LA735 and S. parviflorum LA2072. We also confirmed the tolerance which was reported previously in S. peruvianum LA2157, S. peruvianum PI127829, S. peruvianum LA385, S. habrochaites LA407 and S. lycopersicum cv. IRAT L3. No immunity was found. Also accessions showing a low disease score still contained high titers of bacteria as determined by a dilution plating method, using tow selective media. These results were confirmed with a TaqMan real time PCR assay, which was developed to determine and quantify Cmm in planta