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Article|01 Jan 2021|OPEN
Plant buffering against the high-light stress-induced accumulation of CsGA2ox8 transcripts via alternative splicing to finely tune gibberellin levels and maintain hypocotyl elongation
Bin Liu1,2, Shuo Zhao1, Pengli Li1, Yilu Yin1, Qingliang Niu1, Jinqiang Yan3,4 & Danfeng Huang1,
1School of Agriculture and Biology, Shanghai Jiao Tong University, Key Laboratory of Urban Agriculture (South), Ministry of Agriculture, Dongchuan Road, Shanghai 200240, China
2Department of Plant Genomics, Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Bellaterra 08193, Spain
3Vegetable Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
4Guangdong Key Laboratory for New Technology Research of Vegetables, Guangzhou 510640, China

Horticulture Research 8,
Article number: 2 (2021)
doi: 10.1038/hortres.2021.2
Views: 366

Received: 12 May 2020
Revised: 13 Sep 2020
Accepted: 17 Oct 2020
Published online: 01 Jan 2021

Abstract

In plants, alternative splicing (AS) is markedly induced in response to environmental stresses, but it is unclear why plants generate multiple transcripts under stress conditions. In this study, RNA-seq was performed to identify AS events in cucumber seedlings grown under different light intensities. We identified a novel transcript of the gibberellin (GA)-deactivating enzyme Gibberellin 2-beta-dioxygenase 8 (CsGA2ox8). Compared with canonical CsGA2ox8.1, the CsGA2ox8.2 isoform presented intron retention between the second and third exons. Functional analysis proved that the transcript of CsGA2ox8.1 but not CsGA2ox8.2 played a role in the deactivation of bioactive GAs. Moreover, expression analysis demonstrated that both transcripts were upregulated by increased light intensity, but the expression level of CsGA2ox8.1 increased slowly when the light intensity was >400 µmol·m−2·s−1 PPFD (photosynthetic photon flux density), while the CsGA2ox8.2 transcript levels increased rapidly when the light intensity was >200 µmol·m−2·s−1 PPFD. Our findings provide evidence that plants might finely tune their GA levels by buffering against the normal transcripts of CsGA2ox8 through AS.