Effect of Meloidogyne ethiopica parasitism on water management and physiological stress in tomato
- 401 Downloads
Root-knot nematodes (RKN) are obligate endoparasites that severely damage the host root system. Nutrient and water uptake are substantially reduced in infested plants, resulting into altered physiological processes and reduced plant growth. The effect of nematode infestation on the morphological changes of roots and subsequent physiological plant responses of infested tomatoes with the RKN Meloidogyne ethiopica was studied in a pot experiment. Plants were infested with two inoculum densities (10 or 50 eggs per cm3 substrate) and its effect was evaluated 74 and 102 days post inoculation (DPI). Morphological changes and root growth was determined by analysing scanned images of the whole root system. Nematode infestation reduced the portion of fine roots and increased that of coarse roots due to gall formation. Fine roots of non-infested control plants represented around 51% of the area of the whole root system at 74 and 102 DPI. In comparison to controls, plants inoculated with low and high nematode density had 2.1 and 3.2-times lower surface area of fine roots at 102 DPI. Root analyses revealed that plants had a very limited ability to mitigate the effects of the root-knot nematodes infestation by altering root growth. Root galls had a major influence on the hydraulic conductivity of the root system, which was significantly reduced. The low leaf water potential of infested plants coincided with decreased stomatal conductivity, transpiration and photosynthesis. The latter two were reduced by 60–70% when compared to non-infested control plants.
KeywordsLeaf water potential Root hydraulic conductivity Root morphology Root-knot nematodes Photosynthesis
This research was financially supported by the grant L4-1021 of the Slovenian Research Agency and the Ministry of Agriculture, Forestry and Food of the Republic of Slovenia. The authors thank to Dr. Hans-Josef Schroers for critically reviewing the manuscript.
- Di Vito, M., Parisi, B., & Catalano, F. (2004). Effect of population densities of Meloidogyne incognita on common bean. Nematologia Mediterranea, 32, 81–85.Google Scholar
- Di Vito, M., Magunacelaya, J. C., Ahumada, T., & Catalano, F. (2009). Relationships between initial population densities of Meloidogyne ethiopica and growth of vinifera grape in pots. Nematologia Mediterranea, 37, 105–108.Google Scholar
- Hussey, R. S., & Barker, K. R. (1973). A comparison of methods of collecting inocula of Meloidogyne spp. including a new technique. Plant Disease Reporter, 57, 1025–1028.Google Scholar
- Jaleel, C. A., Manivannan, P., Lakshmanan, G. M. A., Gomathinayagam, M., & Panneerselvam, R. (2008). Alterations in morphological parameters and photosynthetic pigment responses of Catharanthus roseus under soil water deficit. Colloids and Surfaces. B, Biointerfaces, 61, 298–303.PubMedCrossRefGoogle Scholar
- Jaleel, C. A., Manivannan, P., Wahid, A., Farooq, M., Somasundaram, R., & Panneerselvam, R. (2009). Drought stress in plants: a review on morphological characterisation. International Journal of Agriculture and Biology, 11, 100–105.Google Scholar
- Poskuta, J. W., Dropkin, V. H., & Nelson, C. J. (1986). Photosynthesis, photorespiration and respiration of soybean after infection with root nematodes. Photosynthetica, 20, 405–410.Google Scholar
- Ramakrishnan, S., & Rajendran, G. (1998). Influence of Meloidogyne incognita on yield components and physiological functions of papaya. Nematologia Mediterranea, 26, 225–228.Google Scholar
- Širca, S., Urek, G., & Karssen, G. (2004). First report of the root-knot nematode Meloidogyne ethiopica on tomato in Slovenia. Plant Disease, 88, 680.Google Scholar
- Šircelj, H., & Batič, F. (2007). Evaluation of selected nutritional factors in Aposeris foetida (L.) Less. during the harvesting period. Journal of Applied Botany and Food Quality, 81, 121–125.Google Scholar
- Strajnar, P., Širca, S., Geric Stare, B., & Urek, G. (2009). Characterization of the root-knot nematode, Meloidogyne ethiopica Whitehead, 1968, from Slovenia. Russian Journal of Nematology, 17, 135–142.Google Scholar
- Taylor, A. L., & Sasser, J. N. (1978). Biology, identification and control of root-knot nematodes (Meloidogyne spp). Raleigh: North Carolina State University.Google Scholar