Functional characterization of protease inhibitors involved in induced systemic defenses in poplar
Doctoral thesis
Date of Examination:2023-11-14
Date of issue:2024-02-05
Advisor:Prof. Dr. Andrea Polle
Referee:Prof. Dr. Andrea Polle
Referee:Prof. Dr. Ivo Feußner
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Abstract
English
Plants are constantly challenged with biotic stresses. Stresses are gaining importance due to climate change, where extended periods of warmer conditions are expected globally. Extended warmer temperatures also mean longer breeding cycles for herbivores and additional opportunities for pathogen proliferation. To encounter these challenges, plants often employ direct defenses mediated through phytohormones like JA (jasmonic acid) and SA (salicylic acid), and defense proteins like protease inhibitors. Among the protease inhibitors, Kunitz Trypsin Inhibitors (KTI) are known for their anti-nutritive activities against herbivores. KTIs inhibit trypsin, a prominent class of serine proteases involved in the dietary breakdown of food in the insect gut. Recent studies have also observed that KTI transcript levels were systemically induced in P. x canescens leaves during colonization of the roots with the ectomycorrhizal (EM) fungus Laccaria bicolor. Since knowledge of this important class of proteins in poplar was lacking, I focused my study on KTIs. My aim in this Ph.D. study was to functionally characterize the roles of the EM-induced candidate KTI genes against the biotic stresses.
Keywords: Protease inhibitor; Laccaria bicolor; Induced Systemic Resistance; Poplar; Kunitz Trypsin Inhibitor