AUTHOR=Aghajanzadeh Tahereh , Hawkesford Malcolm J. , De Kok Luit J. 

TITLE=The significance of glucosinolates for sulfur storage in Brassicaceae seedlings

JOURNAL=Frontiers in Plant Science

VOLUME=5

YEAR=2014

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2014.00704

DOI=10.3389/fpls.2014.00704

ISSN=1664-462X

ABSTRACT=<p><italic>Brassica juncea</italic> seedlings contained a twofold higher glucosinolate content than <italic>B. rapa</italic> and these secondary sulfur compounds accounted for up to 30% of the organic sulfur fraction. The glucosinolate content was not affected by H<sub>2</sub>S and SO<sub>2</sub> exposure, demonstrating that these sulfur compounds did not form a sink for excessive atmospheric supplied sulfur. Upon sulfate deprivation, the foliarly absorbed H<sub>2</sub>S and SO<sub>2</sub> replaced sulfate as the sulfur source for growth of <italic>B. juncea</italic> and <italic>B. rapa</italic> seedlings. The glucosinolate content was decreased in sulfate-deprived plants, though its proportion of organic sulfur fraction was higher than that of sulfate-sufficient plants, both in absence and presence of H<sub>2</sub>S and SO<sub>2</sub>. The significance of myrosinase in the <italic>in situ</italic> turnover in these secondary sulfur compounds needs to be questioned, since there was no direct co-regulation between the content of glucosinolates and the transcript level and activity of myrosinase. Evidently, glucosinolates cannot be considered as sulfur storage compounds upon exposure to excessive atmospheric sulfur and are unlikely to be involved in the re-distribution of sulfur in <italic>B. juncea</italic> and <italic>B. rapa</italic> seedlings upon sulfate deprivation.</p>