Browsing by Subject "plant defense"

Sort by: Order: Results:

Now showing items 1-3 of 3
  • Jaber, Emad; Kovalchuk, Andriy; Raffaello, Tommaso; Keriö, Susanna; Teeri, Teemu; Asiegbu, Fred O. (2018)
    Both the establishment of sustainable forestry practices and the improvement of commercially grown trees require better understanding of mechanisms used by forest trees to combat microbial pathogens. We investigated the contribution of a gene encoding Scots pine (Pinus sylvestris L.) antimicrobial protein Sp-AMP2 (PR-19) to the host defenses to evaluate the potential of Sp-AMP genes as molecular markers for resistance breeding. We developed transgenic tobacco plants expressing the Sp-AMP2 gene. Transgenic plants showed a reduction in the size of lesions caused by the necrotrophic pathogen Botrytis cinerea. In order to investigate Sp-AMP2 gene expression level, four transgenic lines were tested in comparison to control and non-transgenic plants. No Sp-AMP2 transcripts were observed in any of the control and non-transgenic plants tested. The transcript of Sp-AMP2 was abundantly present in all transgenic lines. Sp-AMP2 was induced highly in response to the B. cinerea infection at 3 d.p.i. This study provides an insight into the role of Sp-AMP2 and its functional and ecological significance in the regulation of plant–pathogen interactions.
  • Xue, Yaxin (Helsingfors universitet, 2016)
    Previous research has demonstrated that biochar added to soil improves plant performance. When widely used, biochar can help reduce the consumption of chemical pesticides and fertilizers. The aim of this study is to explore whether biochar can help strawberry (Fragaria × ananassa) plants in greenhouse to fight against foliar disease, gray mold caused by Botrytis cinerea. Disease progress was estimated after infection. Nine days after inoculation, the biomass of leaves and root were quantified to reflect the plant growth during inflection. In 2013, three types of birch biochar with different chemical compositions were tested. The best performing of biochar were selected for 2014 assay at the rate of 5.4%. Based on data obtained in 2013 and 2014, both 3% and 5.4% birch biochar amendment are able to retard gray mold development in the beginning of the infection, but disease severity finally reaches the same level on the ninth day after Botrytis cinerea inoculation. We also found that 5.4% birch biochar results in significantly increased electrical conductivity and less water consumption in peat soil. Finally, we propose that higher concentrations of biochar might more benefit the plant growth rather than contributing to plant defense. However, evidence at the molecular level is still needed to support our hypothesis.
  • Denham, Sander; Coyle, David; Oishi, Andrew; Bullock, Bronson P; Heliövaara, Kari Tapani; Novick, Kimberly A (2019)
    The success of tree colonization by bark beetles depends on their ability to overcome host tree defenses, including resin exudation and toxic chemicals, which deter bark beetle colonization. Resin defenses during insect outbreaks are challenging to study in situ, as outbreaks are stochastic events that progress quickly and thus preclude the establishment of baseline observations of non-infested controls. We use synthetic aggregation pheromones to demonstrate that confined Ips bark beetle herbivory can be successfully initiated to provide opportunities for studying interactions between bark beetles and their hosts, including the dynamics of constitutive and induced resin exudation. In Pinus taeda L. plantations between 12 and 19 years old in North and South Carolina, U.S., trees were affixed with pheromone lures, monitored for evidence of bark beetle attacks, and resin samples were collected throughout the growing season. Baiting increased beetle herbivory to an extent sufficient to produce an induced resin response. Attacked trees exuded about three times more resin at some time than control trees. This supports previous work that demonstrated that information on constitutive resin dynamics alone provides an incomplete view of a host tree's resistance to bark beetle attack.