Skip to Content
Merck
  • The infection biology of Sphaerulina musiva: clues to understanding a forest pathogen.

The infection biology of Sphaerulina musiva: clues to understanding a forest pathogen.

PloS one (2014-07-30)
Ruqian Qin, Jared M LeBoldus
ABSTRACT

Trees in the genus Populus and their interspecific hybrids are used across North America for fiber production and as a potential source of biofuel. Plantations of these species are severely impacted by a fungal pathogen, Sphaerulina musiva, the cause of leaf spot and stem canker. An inoculation protocol that does not rely on stem wounding to achieve infection was recently developed. Using this protocol two experiments were conducted to examine infection biology and disease development in the S. musiva-Populus interaction. In the first experiment non-wounded stems of one moderately resistant clone (NM6) and one susceptible clone (NC11505) were inoculated and examined by scanning electron microscopy at six different times (6 h, 12 h, 24 h, 72 h, 1 week, and 3 weeks) post-inoculation. The images indicate that the pathogen appears to enter host tissue through small openings and lenticels and that there are no significant differences in the penetration rate between the moderately resistant (NM6) and susceptible (NC11505) clones at 12 h post-inoculation. In a second experiment a histological comparison of stem cankers for resistant clone DN74 and susceptible clone NC11505 were conducted at three time points (3 weeks, 5 weeks, and 7 weeks) post-inoculation. Distinct differences in disease development were apparent between the resistant and susceptible clones at each time point, with the susceptible clone exhibiting a weak and delayed defense response. These results suggest, that following penetration, the pathogen may be able to interfere with the defense response in the susceptible host.

MATERIALS
Product Number
Brand
Product Description

USP
Calcium Carbonate (AS), United States Pharmacopeia (USP) Reference Standard
Sigma-Aldrich
Calcium carbonate, ACS reagent, chelometric standard, 99.95-100.05% dry basis
Sigma-Aldrich
Calcium carbonate, BioUltra, precipitated, ≥99.0% (KT)
Sigma-Aldrich
Calcium carbonate, tested according to Ph. Eur.
Sigma-Aldrich
Calcium carbonate, ≥99.995% trace metals basis
Sigma-Aldrich
Calcium carbonate, 99.999% trace metals basis
Sigma-Aldrich
Calcium carbonate, powder, ≤50 μm particle size, 98%
Sigma-Aldrich
Calcium carbonate, BioReagent, suitable for insect cell culture, ≥99.0%
Sigma-Aldrich
Calcium carbonate, BioXtra, ≥99.0%
Supelco
Calcium carbonate, reference material for titrimetry, certified by BAM, ≥99.5%
Sigma-Aldrich
Calcium carbonate, puriss., meets analytical specification of Ph. Eur., BP, USP, FCC, E170, precipitated, 98.5-100.5% (based on anhydrous substance)
Supelco
Calcium carbonate, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
Calcium carbonate, ReagentPlus®
Sigma-Aldrich
Calcium carbonate, ACS reagent, ≥99.0%, powder