Journal of Plant Pathology (2010) 92, 421-428

L. Ni, L. Guo, J.B.M. Custers and L. Zhang (2010)
Characterization of calla lily soft rot caused by Pectobacterium carotovorum subsp. carotovorum ZT0505: Bacterial growth and pectate lyase activity under different conditions
Journal of Plant Pathology 92 (2), 421-428
Abstract: Soft rot is a major disease of calla lily (Zantedeschia spp.) and other important crops worldwide. In this report, the bacterial isolate ZT0505 proved to be a soft rot pathogen of calla lily growing around Kunming (subtropical China) and was identified as Pectobacterium carotovorum subsp. carotovorum. The weight of macerated tuber tissue caused by inoculation of the isolate and incubation for 36 h at 22, 25, 28 and 32°C, was 0.21, 0.62, 0.67, and 0.60 g/tuber, respectively. The extent of tuber maceration was significantly less (65.0-68.7%) at 22°C than at 25-32°C, while 28°C yielded the highest amount of macerated tissue. The bacterium grew faster at 32°C than at 22-28°C. The highest pectate lyase (PL) activity of isolate ZT0505 was found at 28°C, a value much higher than the 14-17°C range at which P. carotovorum subsp. carotovorum strains from more temperate regions are usually found to have the highest PL activity. Temperature effect on PL activity tallied with that on tuber maceration. After 24 h incubation at pH 6.3, 7.0, 7.3, the weight of macerated tissue was 0.17, 0.61, 0.61 g/tuber, respectively. The extent of maceration increased when lengthening the incubation time. Tuber maceration at pH 6.3 was significantly less (54.9-72.1%) than at pH 7.0 and 7.3 after 24-36 h incubation. Bacterial growth at pH 6.3 was significant slower than at pH 7.0 and 7.3. A good correlation between PL activity and extent of tuber maceration at the various pHs was found only when PL activity assays were conducted at similar pHs.
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Research topic(s) for pests/diseases/weeds:
rearing/culturing/mass production
environment - cropping system/rotation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Pectobacterium carotovorum	Zantedeschia (genus)	China (south)