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- Title
qRT-PCR analysis of key enzymatic genes related to phenolic acid metabolism in rice accessions (Oryza Sativa L.) exposed to low nitrogen treatment.
- Authors
Xiong, J.; Wang, H. B.; Qiu, L.; Wu, H. W.; Chen, R. S.; He, H. B.; Lin, R. Y.; Lin, W. X.
- Abstract
The differential expressions of key enzyme genes involved in Phenylalanine metabolism pathway in allelopathic rice, PI312777 and its counterpart, Lemont under low nitrogen treatment were investigated using real-time fluorescence quantitative PCR(qRT-PCR). The expressions of all nine enzymatic genes involved in phenolic synthesis were increased by 2.3-6.0 folds in the leaves and by 1.9-5.4 folds in the roots of allelopathic rice, PI312777, respectively. Two genes encoding CoA-ligase and salicylate glucosyl transferase, showed 1.7 and 2.3 folds down-regulations in the leaves respectively, when exposed to the lower nitrogen supply. However, in the non-allelopathic rice (Lemont), the expressions of these genes were mostly down-regulated from 1.4 to 3.5 times in the roots and from 1.2 to 4.0 times in the leaves, with the exception of cinnamoyl alcohol dehydrogenases up-regulated by 1.5 folds in the leaves, PAL and Cinnamoyl-CoA up-regulated by 1.0 and 1.4 folds respectively in the roots. HPLC analysis confirmed that allelopathic rice had an increased exudation of phenolic compounds when supplied with lower nitrogen, resulting in an elevanted allelopathic activity, while little change occurred in non-allelopathic rice. Further analysis suggested that the nutrient-stressed condition might induce the synthesis of signal molecules such as SA, then trigger a cascade of systemic chemical defence reactions through up-regulated expressions of relevant genes involved in phenylpropanoid metabolism pathway because of the decreased demand for proteins required for rice growth when exposed to low nitrogen supply. In this process, ammonium ions released by PAL can be assimilated to increase N cycling for compensating nitrogen deficiency. The resulting N-free carbon skeletons of t-cinnamate can be shunted into phenylpropanoid metabolism. This in turn resulted in increased production of phenolic compounds. Thus the increase of phenolic acids enhanced the allelopathic potential in rice, when exposed to lower nitrogen supply, in others words, phenolic acids as allelochemicals played a key role in rice allelopathy, especially in environmental stress.
- Subjects
RICE; NITROGEN; AMINO acids; GENES; PHENOLS; DEHYDROGENASES
- Publication
Allelopathy Journal, 2010, Vol 25, Issue 2, p345
- ISSN
0971-4693
- Publication type
Article