Suppression of the β-carotene hydroxylase gene increases β-carotene content and tolerance to abiotic stress in transgenic sweetpotato plants

Le Kang, Chang Yoon Ji, Sun Ha Kim, Qingbo Ke, Sung Chul Park, Ho Soo Kim, Hyeong Un Lee, Joon Seol Lee, Woo Sung Park, Mi Jeong Ahn, Haeng Soon Lee, Xiping Deng, Sang Soo Kwak

Research output: Contribution to journalArticlepeer-review

59 Scopus citations

Abstract

β-carotene, a carotenoid that plays a key photo-protective role in plants is converted into zeaxanthin by β-carotene hydroxylase (CHY-β). Previous work showed that down-regulation of IbCHY-β by RNA interference (RNAi) results in higher levels of β-carotene and total carotenoids, as well as salt stress tolerance, in cultured transgenic sweetpotato cells. In this study, we introduced the RNAi-IbCHY-β construct into a white-fleshed sweetpotato cultivar (cv. Yulmi) by Agrobacterium-mediated transformation. Among the 13 resultant transgenic sweetpotato plants (referred to as RC plants), three lines were selected for further characterization on the basis of IbCHY-β transcript levels. The RC plants had orange flesh, total carotenoid and β-carotene contents in storage roots were 2-fold and 16-fold higher, respectively, than those of non-transgenic (NT) plants. Unlike storage roots, total carotenoid and β-carotene levels in the leaves of RC plants were slightly increased compared to NT plants. The leaves of RC plants also exhibited tolerance to methyl viologen (MV)-mediated oxidative stress, which was associated with higher 2,2-diphenyl-1- picrylhydrazyl (DPPH) radical-scavenging activity. In addition, RC plants maintained higher levels of chlorophyll and higher photosystem II efficiency than NT plants after 250 mM NaCl stress. Yield of storage roots did not differ significantly between RC and NT plants. These observations suggest that RC plants might be useful as a nutritious and environmental stress-tolerant crop on marginal lands around the world.

Original languageEnglish
Pages (from-to)24-33
Number of pages10
JournalPlant Physiology and Biochemistry
Volume117
DOIs
StatePublished - Aug 2017

Keywords

  • Carotenoid
  • Oxidative stress
  • RNA interference
  • Salt stress
  • Sweetpotato
  • β-carotene hydroxylase

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