Abstract
Although the degradation pathway of purine bases constitutes one of the fundamentals of plant nitrogen metabolism, the physiological function of this catabolism remains unclear. Previously, we unmasked that RNAi-mediated knockdown of xanthine dehydrogenase (XDH), the first enzyme in purine catabolism, not only impairs normal growth and development, but also causes the hypersensitivity to drought stress in Arabidopsis [1,2]. Recently, we found that transient accumulation of osomoprotectant proline, a typical example of plant stress response, was diminished in XDH-knockdown plants exposed to drought shock. Coincident with this observation, real-time PCR analysis revealed that stress-induced gene expression of proline metabolism was somehow altered in these plants. The results suggest that there exists the possibility of physiological connection between purine degradation and proline accumulation, which might influence the acclimatization process to stress in Arabidopsis.
[1] Nakagawa et al. (2007) Plant Cell Physiol. 48: 1484-1495
[2] Watanabe et al. (2010) FEBS Lett. 584: 1181-1186.
