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Endogenous salicylic acid protects rice plants from oxidative damage caused by aging as well as biotic and abiotic stress

Endogenous salicylic acid protects rice plants from oxidative damage caused by aging as well as... Salicylic acid (SA) is a key endogenous signal that mediates defense gene expression and disease resistance in many dicotyledonous species. In contrast to tobacco and Arabidopsis, which contain low basal levels of SA, rice has two orders of magnitude higher levels of SA and appears to be insensitive to exogenous SA treatment. To determine the role of SA in rice plants, we have generated SA‐deficient transgenic rice by expressing the bacterial salicylate hydroxylase that degrades SA. Depletion of high levels of endogenous SA in transgenic rice does not measurably affect defense gene expression, but reduces the plant's capacity to detoxify reactive oxygen intermediates (ROI). SA‐deficient transgenic rice contains elevated levels of superoxide and H2O2, and exhibits spontaneous lesion formation in an age‐ and light‐dependent manner. Exogenous application of SA analog benzothiadiazole complements SA deficiency and suppresses ROI levels and lesion formation. Although an increase of conjugated catechol was detected in SA‐deficient rice, catechol does not appear to significantly affect ROI levels based on the endogenous catechol data and exogenous catechol treatment. When infected with the blast fungus (Magnaporthe grisea), SA‐deficient rice exhibits increased susceptibility to oxidative bursts elicited by avirulent isolates. Furthermore, SA‐deficient rice is hyperresponsive to oxidative damage caused by paraquat treatment. Taken together, our results strongly suggest that SA plays an important role to modulate redox balance and protect rice plants from oxidative stress. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Plant Journal Wiley

Endogenous salicylic acid protects rice plants from oxidative damage caused by aging as well as biotic and abiotic stress

Yang, Yinong; Qi, Min; Mei, Chuansheng
The Plant Journal , Volume 40 (6) – Dec 1, 2004
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References (65)

Publisher
Wiley
Copyright
Copyright © 2004 Wiley Subscription Services, Inc., A Wiley Company
ISSN
0960-7412
eISSN
1365-313X
DOI
10.1111/j.1365-313X.2004.02267.x
pmid
15584956
Publisher site
See Article on Publisher Site

Abstract

Salicylic acid (SA) is a key endogenous signal that mediates defense gene expression and disease resistance in many dicotyledonous species. In contrast to tobacco and Arabidopsis, which contain low basal levels of SA, rice has two orders of magnitude higher levels of SA and appears to be insensitive to exogenous SA treatment. To determine the role of SA in rice plants, we have generated SA‐deficient transgenic rice by expressing the bacterial salicylate hydroxylase that degrades SA. Depletion of high levels of endogenous SA in transgenic rice does not measurably affect defense gene expression, but reduces the plant's capacity to detoxify reactive oxygen intermediates (ROI). SA‐deficient transgenic rice contains elevated levels of superoxide and H2O2, and exhibits spontaneous lesion formation in an age‐ and light‐dependent manner. Exogenous application of SA analog benzothiadiazole complements SA deficiency and suppresses ROI levels and lesion formation. Although an increase of conjugated catechol was detected in SA‐deficient rice, catechol does not appear to significantly affect ROI levels based on the endogenous catechol data and exogenous catechol treatment. When infected with the blast fungus (Magnaporthe grisea), SA‐deficient rice exhibits increased susceptibility to oxidative bursts elicited by avirulent isolates. Furthermore, SA‐deficient rice is hyperresponsive to oxidative damage caused by paraquat treatment. Taken together, our results strongly suggest that SA plays an important role to modulate redox balance and protect rice plants from oxidative stress.

Journal

The Plant Journal – Wiley

Published: Dec 1, 2004

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