Functional characterization of WRKY75 transcription factor in SA signalling and cell death by using lesion mimic mutants

Show full item record



Permalink

http://urn.fi/URN:NBN:fi:hulib-202101261354
Title: Functional characterization of WRKY75 transcription factor in SA signalling and cell death by using lesion mimic mutants
Author: Zhou, Quan
Contributor: University of Helsinki, Faculty of Biological and Environmental Sciences
Publisher: Helsingin yliopisto
Date: 2020
Language: eng
URI: http://urn.fi/URN:NBN:fi:hulib-202101261354
http://hdl.handle.net/10138/325259
Thesis level: master's thesis
Degree program: Kasvitieteen maisteriohjelma
Master 's Programme in Integrative Plant Sciences
Magisterprogrammet i botanik
Specialisation: Genetiikka ja genomiikka
Genetics and Genomics
Genetik och genomik
Abstract: Leaf senescence is a developmental and physiological phase in plants to end leaf development. Environment factors such as drought stress, extreme temperature, and pathogen threat and internal factors including age and reactive oxygen species induce leaf senescence. Some phytohormones such as jasmonic acid and salicylic acid play a key function in cell death in plants. WRKY transcription factors is known as one of the largest transcription factor family in plants which regulates a variety of plants processes. WRKY75 which belong to WRKY transcription factors has shown multiple functions in plant development like regulation of Pi starvation responses and root development and flowering. In my thesis, I focused on the role of WRKY75 in senescence and stress responses. WRKY75 was identified as a positive regulator of cell death in Arabidopsis. WRKY75 can promote salicylic acid biosynthesis by promote transcript levels of SID2 and also cause hydrogen peroxide accumulation by suppressing the transcription of CAT2. Hydrogen peroxide and salicylic acid can promote WRKY75 transcription at the same time. To evaluate the function of WRKY75 transcription factor in SA signalling and cell death, three lesion mimic mutants acd5, cat2, dnd1 and their corresponding wrky75 double mutant were used. Interestingly, no different phenotypes were found between acd5, cat2, dnd1 and their corresponding wrky75 double mutants in cell death and hydrogen peroxide accumulation detection in Arabidopsis leaves. Meanwhile, marker genes transcription levels were not different in both short day and long day growth condition. However, different phenotypes were observed in botrytis infection. Based on these results, we formed a hypothesis that gene redundancy could influence genetic characterization of WRKY75. To overcome this problem, SRDX-WRKY75 chimeric repressor transgenic lines were generated. The SRDX domain act as a dominant negative regulator to suppress WRKY75 target genes. In future research, these new lines can be used to test transcript levels for putative WRKY75 target genes.
Subject: WRKY75
Salicylic acid
ROS
SRDX


Files in this item

Total number of downloads: Loading...

Files Size Format View
Zhou_Quan_thesis_2020.pdf 3.749Mb PDF View/Open

This item appears in the following Collection(s)

Show full item record