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Volume 3
Journal of Pharmacology and Medicinal Chemistry
Nanomedicine 2019
Biotechnology 2019
May 20-21, 2019
May 20-21, 2019 London, UK
4
th
World Biotechnology CONGRESS
Nanomedicine and Nanotechnology
4
th
International Conference on
&
Constitutive and induced resistance to pathogens in conifers: An integrated view of
molecular, anatomical and chemical responses
Adriana Arango-Velez
Florida A&M University, USA
C
onifers defenses against herbivores have been challenged by climate change, allowing the expansion in range and
frequency of bark beetles and their associated pathogens, into previously unexplored areas. Two of the most aggressive
bark beetles (the mountain – MPB- and southern pine beetle -SPB-) are attacking naive hosts in forested areas of Canada
and the U.S, where prior colonization by these pests were unforeseen. As these beetles use pathogenic fungi to modify host
tissues to favor brood development and overcome tree defenses, fungal associations are crucial for beetle success. To evaluate
constitutive (pre-attack) and induced (post-attack) responses of conifer trees, two independent studies were conducted using
the MPB and SPB associated pathogenic fungi Grosmania clavigera and Ophiosoma minus at 1-, 7- and 28- and 62-days post
inoculation respectively. To understand the complex interactions that modulate tree defense responses, we performed (i)
microarray and targeted gene expression analyses (chitinases and terpene synthases), under well-watered and water deficit
conditions (ii) UHPLC and GC-MS chemical profiling of phenols and terpenoids, (iii) phyohormones and iv) histochemical
analyses, in coevolved and naive pine trees. Results show that upon pathogen attack, jasmonic and salicylic acid were
implicated in local and systemic response to fungal inoculation; in addition, an increased transcript expression of chitinases,
pathogenesis-related genes, as well as genes associated with jasmonate and ethylene signaling were observed. Differences in
expression patterns due to fungal inoculation were observed between naïve and coevolved species (Fig. 1). Chemical analyses
showed induction of epi/catechin, three unknown phenolic compounds and several phloem terpenoids (α-pinene, β-myrcene,
limonene, terpinolene and α-pinene) indicating an elevated tree response against pathogen attack. Lastly, histochemical
analyses demonstrated the capacity of naïve pine trees to induce traumatic resin ducts production and lesion development to
confine fungal development. Taken together these responses, naïve and coevolved conifers respond differently to fungal attack.
adrianaa@ualberta.caJ Pharmacol Med Cheml, Volume 3