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Regulation of the Phenylpropanoid Pathway: A Mechanism of Selenium Tolerance in Peanut (Arachis hypogaea L.) Seedlings

Wang, Guang, Wu, Liying, Zhang, Hong, Wu, Wenjia, Zhang, Mengmeng, Li, Xiaofeng, Wu, Hui
Journal of agricultural and food chemistry 2016 v.64 no.18 pp. 3626-3635
Arachis hypogaea, biosynthesis, chalcone isomerase, endodermis, enzyme activity, flavonoids, gene expression, gene expression regulation, hydrogen peroxide, lignin, naringenin-chalcone synthase, nitric oxide, peanuts, phenolic acids, phenylalanine ammonia-lyase, phenylpropanoids, polyphenols, roots, seedlings, selenium, sodium selenite, soil
To clarify the mechanisms of selenium (Se) tolerance in peanut seedlings, we grew peanut seedlings with sodium selenite (0, 3, and 6 mg/L), and investigated the phenylpropanoids metabolism in seedling roots. The results showed that selenite up-regulated the expression of genes and related enzyme activities involving in the phenylpropanoids biosynthesis cascade, such as phenylalanine ammonia-lyase, trans-cinnamate-4-hydroxylase, chalcone synthase, chalcone isomerase, and cinnamyl-alcohol dehydrogenase. Selenite significantly increased phenolic acids and flavonoids, which contributed to the alleviation of selenite-induced stress. Moreover, selenite enhanced the formation of endodermis in roots, which may be attributed to the up-regulation of lignin biosynthesis mediated by the selenite-induced changes of H2O2 and NO, which probably regulated the selenite uptake from an external medium. Accumulation of polyphenolic compounds via the phenylpropanoid pathway may be one of the mechanisms of the increasing selenite tolerance in plants, by which peanut seedlings survived in seleniferous soil, accompanied by accumulation of Se.