Details

Autor(en) / Beteiligte

• Hoang, Nam V.
• Park, Suhyoung
• Park, Chulmin
• Suh, Hannah
• Kim, Sang‐Tae
• Chae, Eunyoung
• Kang, Byoung‐Cheorl
• Lee, Ji‐Young

Titel

Oxidative stress response and programmed cell death guided by NAC013 modulate pithiness in radish taproots

Ist Teil von

• The Plant journal : for cell and molecular biology, 2022-01, Vol.109 (1), p.144-163

Ort / Verlag

England: Blackwell Publishing Ltd

Erscheinungsjahr

2022

Quelle

Wiley-Blackwell Journals

Beschreibungen/Notizen

• SUMMARY Radish, Raphanus sativus L., is an important root crop that is cultivated worldwide. Owing to its evolutionary proximity to Arabidopsis thaliana, radish can be used as a model root crop in research on the molecular basis of agronomic traits. Pithiness is a significant defect that reduces the production of radish with commercial value; however, traditional breeding to eliminate this trait has thus far been unsuccessful. Here, we performed transcriptomics and genotype‐by‐sequencing (GBS)‐based quantitative trait locus (QTL) analyses of radish inbred lines to understand the molecular basis of pithiness in radish roots. The transcriptome data indicated that pithiness likely stems from the response to oxidative stress, leading to cell death of the xylem parenchyma during the root‐thickening process. Subsequently, we narrowed down a list of candidates responsible for pithiness near a major QTL and found polymorphisms in a radish homologue of Arabidopsis ANAC013 (RsNAC013), an endoplasmic reticulum bound NAC transcription factor that is targeted to the nucleus to mediate the mitochondrial retrograde signal. We analysed the effects of polymorphisms in RsNAC013 using Arabidopsis transgenic lines overexpressing RsNAC013 alleles as well as in radish inbred lines bearing these alleles. This analysis indicated that non‐synonymous variations within the coding sequence result in different levels of RsNAC013 activities, thereby providing a genetic condition for root pithiness. The elevated oxidative stress or hypoxia that activates RsNAC013 for mitochondrial signalling enhances this process. Collectively, this study serves as an exemplary case of translational research taking advantage of the extensive information available from a model organism. Significance Statement This study is an exemplary translational research employing extensive information available from a model organism. To find the molecular basis of root pithiness, a significant defect reducing the commercial value of radish taproots, we performed transcriptomics and QTL analyses, compared these results with regulatory networks in Arabidopsis, and thereby found that the pithiness is mediated by NAC013, a transcription factor activating the oxidative stress response that leads to cell death in radish taproots.