Abstract Detail



Ecophysiology

Lim-Hing , Simone [1], Gandhi, Kamal JK [2], Barnes, Brittany F [3], Morrison, Lawrence A [2], McCarty, Elizabeth [4], Villari, Caterina [5].

Untangling the micronutrient status and defense responses in loblolly pine (Pinus taeda).

 Trees are large, long-lived organisms that are critical for carbon sequestration, ecosystem services, and provide habitats for other organisms. However, they are subject to many stressors, particularly biotic agents, such as diseases that adversely affect tree health in both in managed and unmanaged forests. Trees have evolved an arsenal of defenses to combat pathogens, however disease outbreaks have become more erratic, frequent, and severe due to climate change and the often invasive nature of pathogens. While considerable progress has been made on disease dynamics and host-pathogen interactions, there are still many unknowns e.g., the effects of micronutrients on tree physiology and defense. Manganese (Mn), for instance, warrants further investigation, given the recent correlation found between marginally deficient levels of Mn in the soil and higher biotic stress in loblolly pine (Pinus taeda). To determine the influence of Mn-deficiency on the defense capabilities of loblolly pine, we conducted a greenhouse study where loblolly pine seedlings were subjected to different levels of Mn availability for nine months. Trees were subsequently challenged with two necrotrophic pathogens (either Fusarium circinatum or Ophiostoma ips) or mock-inoculated with sterile agar as control at nine months of fertilizer treatment.  The response of the trees in terms of lesion length, physiological parameters, and secondary metabolite production was measured after three weeks. After nine months of fertilizer treatment, Mn deficient trees had lower chlorophyll fluorescence and needles were slightly chlorotic, but there were no differences in height, diameter, water potential, or carbon assimilation. After inoculation, water potential increased, however preliminary analyses show no effect of Mn fertilization levels on necrotic fungal lesion length. To better gauge the impact of Mn deficiency on loblolly pine’s defense mechanisms, secondary metabolite concentration, defense-related gene expression, lignin deposition, and traumatic resin duct formation will be assessed. Mn is a critical component to many specific molecular processes in plant function and plant defense.         


1 - University Of Georgia , Plant Sciences , 2502 Miller Plant Sciences , 120 Carlton St, Athens, GA, 30602, United States
2 - University of Georgia, Warnell School of Forestry and Natural Resources, 180 E Green St, Athens , GA, 30602, USA
3 - University of Georgia, Warnell School of Natural Resources, 180 E Green St, Athens, GA, 30602, USA
4 - University of Georgia, Warnell School of Forestry and Natural Resources, 122 S. Entomology Drive , Tifton, GA, 31793, USA
5 - University of Georgia , Plant Biology, Warnell School of Forestry and Natural Resources, 180 E Green Street , Athens, GA, 30602, USA

Keywords:
plant resistance
micronutrient deficiency
fungal pathogens
plant physiology
forestry.

Presentation Type: Poster Time and date to be determined
Number: PPE001
Abstract ID:305
Candidate for Awards:Physiological Section Physiological Section Li-COR Prize


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