Han L, Dutilleul P, Prasher S O, Beaulieu C, Smith D L
Department of Plant Science, McGill University, Bellevue, Canada.
Phytopathology. 2008 Oct;98(10):1118-25. doi: 10.1094/PHYTO-98-10-1118.
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.
由疮痂链霉菌引起的普通疮痂病是马铃薯（Solanum tuberosum）的一种主要细菌性病害。其最广为人知的症状是在收获时观察到的后代马铃薯块茎表面的浅表病斑。在本研究中，通过计算机断层扫描（CT）扫描研究了疮痂链霉菌在生长过程中对地下器官空间占有率和根系结构复杂性的影响。两组马铃薯植株种植在温室中的中型塑料盆中。使用一台以前用于医疗应用的高分辨率X射线CT扫描仪，在种植后4周、6周和8周对其地下器官和周围介质（过筛并高压灭菌的均质沙子）进行CT扫描。对于一组，在装盆时将沙子接种上引起普通疮痂病的病原体（疮痂链霉菌EF-35）。通过对CT扫描数据直方图应用曲线拟合来估计地下器官的空间占有率，同时使用三维骨骼图像进行分形分析。发现种植后4周，患病植株的根系比健康植株的根系更不复杂，并且从第4周到第8周，两组之间从空间占有率测量得出的相对生长速率具有不同的符号。
