Assessment of Common Scab-Inducing Pathogen Effects on Potato Underground Organs Via Computed Tomography Scanning

Abstract

Common scab caused by Streptomyces scabies is a major bacterial disease of potato (Solanum tuberosum). Its best known symptom is superficial lesions on the surface of progeny potato tubers, observed at harvesting. In this study, effects of S. scabies on space occupancy by underground organs and on structural complexity of root systems are investigated during growth via computed tomography (CT) scanning. Two groups of potato plants were grown in a greenhouse in middle-sized plastic pots. Using a high-resolution X-ray CT scanner formerly used for medical applications, their underground organs and surrounding medium (sieved and autoclaved homogeneous sand) were submitted to CT scanning 4, 6, and 8 weeks after planting. For one group, sand was inoculated with the common scab-inducing pathogen (S. scabies EF-35) at potting. Space occupancy by underground organs was estimated via curve fitting applied to histograms of CT scan data, while three-dimensional skeletal images were used for fractal analysis. Root systems of diseased plants were found to be less complex than those of healthy plants 4 weeks after planting, and the relative growth rates derived from space occupancy measures were of different sign between the two groups from week 4 to week 8.

A multidimensional statistical model for wood data analysis, with density estimated from CT scanning data as an example

“…Configuration parameters in our study were field of view of 18 cm in diameter combined with a zoom factor of 8, tube voltage 120 kV, and tube current 50 mA. The helical scanning mode was chosen because of its advantages in terms of image reconstruction and advanced interpolation, resulting in enhanced image precision (Han et al 2008). The reconstruction interval length was 0.1 mm and a total of 40 CT images were constructed sequentially each time, covering a distance of 4 mm in the central part of the wood sample ( Fig.…”

Dehydrated pork manure by-product: effect of a chitosan amendment on bacterial community and common scab incidence

“…Biosolid P possibly brought nutrients or physicochemical conditions that conferred an advantage to the S. scabies population or that might contribute to a better colonization of the potato seed tubers by the S. scabies. Han et al (2008) suggested that the soil population of common scab-inducing pathogens colonized seed potatoes at planting and modified root development. Alternatively, the microbial community of biosolid P might contribute to the increased level of disease by competing with S. scabies antagonistic agents that colonize soil and potato organs (Liu et al 1995) or by secreting compounds that stimulate toxin biosynthesis in S. scabies (Agbessi et al 2003).…”

Existing and Potential Statistical and Computational Approaches for the Analysis of 3D CT Images of Plant Roots

“…present a nice review of relevant applications [7]. Detection of the plant seed directly is usually not a primary study goal, but new methods are emerging focusing on seed-soil contact areas [45]; in some studies the seed volume is accounted for in the model parameters when estimating root volumes and detecting first-order roots [17], and plants are usually scanned after the first 7-8 days of planting [46].…”

“…It has also been established that the soil substrate influences root anatomy; see, for example, Ahmed et al [11] and Rich and Watt [12]. Important influences on root development may come from abiotic stressors such as drought, salinity, and extreme temperature [13,14] not to mention biotic stressors such as pathogens [15][16][17][18]. One important biotic stressor-or helper-of particular recent interest is the rhizosphere and root-rhizosphere interactions [19][20][21].…”