“Exploring the link between aluminum toxicity and DNA damage in Arabidopsis”

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Tuesday 09 January 2018, 11:00 - 11:40

 
ABSTRACT

Aluminum toxicity is an under recognized issue affecting global agriculture, with Al toxic soils arguably representing upwards of 50% of the world’s arable land.  This is especially problematic for developing agricultural areas such as in equatorial Africa and South America where acid soils that promote formation of the phytotoxic Al3+ species are prevalent.  Substantial efforts have been made to engineer Al resistant crops largely through enhancement of release of Al chelating organic acids, yet the underlying cause of Al dependent stoppage of root growth remains elusive.  Work using Arabidopsis as a model system has suggested that one of the biochemical targets of Al likely is genomic DNA, with Al speculated to interact electrostatically with DNA and having various impacts on DNA that activate the DNA damage response (DDR) in the root tip.  Through analysis of DDR mutants in Arabidopsis, an emerging model that argues for Al3+ acting at least in part as a DNA damage agent has been developed.  In this model, factors that comprise part of the pathway responsible for detection of persistent single strand DNA have been found to be required for normal stoppage of root growth following exposure to Al.  These include the master DDR factor ATR as well as ATRIP, which recruits ATR to persistent single strand DNA such as what occurs at stalled replication forks.  Loss of these factors as well as the key DDR transcription factor, SOG1, results in Al tolerant roots that are capable of sustained root growth in the presence of normally inhibitory levels of Al, thus suggesting that Al-dependent stoppage of root growth is at least in part an active response to Al damage mediated by the ATR-related aspect of the DDR pathway in Arabidopsis roots.

Location Jozef Schell Seminar Room
Contact Prof Paul Larsen
University of California
USA