Abstract
Xanthine dehydrogenase (XDH) is a ubiquitous enzyme involved in purine catabolism. Recently, XDH is implicated in the formation of redox-signaling reactive oxygen and nitrogen species such as superoxide and nitric oxide, proposing a possible new role of this classic enzyme. To evaluate the impact of this enzyme on plant growth and development, we generated transgenic plants of Arabidopsis in which XDH expression was downregulated by RNA interference. Knockdown of XDH resulted in a retarded growth phenotype, and significantly impaired fruit development and seed fertility. In addition, XDH-suppressed plants accelerated leaf senescent process as revealed by the decrease in chlorophyll content with a concomitant activation of senescence-associated genes. These results suggest that XDH plays a vital role in plant growth at both vegetative and reproductive phases, and XDH might take part in the control of physiological processes such as leaf senescence.
