Transcriptomic analysis of Chinese yam (Dioscorea polystachya Turcz.) variants indicates brassinosteroid involvement in tuber development

Frontiers in Nutrition

Nutrition

Janina Epping¹  Jenny Riekötter¹  Jost Muth²  Jana Oklestkova³  Richard M. Twyman⁴ 

[1] Department of Biology, Institute of Plant Biology and Biotechnology, University of Münster, Münster, Germany;Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Aachen, Germany;Laboratory of Growth Regulators, The Czech Academy of Science, Institute of Experimental Botany and Palacký University, Faculty of Science, Olomouc, Czechia;TRM Ltd., Scarborough, United Kingdom;

关键词: Chinese yam;    Dioscorea polystachya;    tuber development;    brassinosteroids;    plant hormones;   

DOI  :  10.3389/fnut.2023.1112793

 received in 2022-11-30, accepted in 2023-04-11,  发布年份 2023

来源: Frontiers

【 摘 要 】

Dioscorea is an important but underutilized genus of flowering plants that grows predominantly in tropical and subtropical regions. Several species, known as yam, develop large underground tubers and aerial bulbils that are used as food. The Chinese yam (D. polystachya Turcz.) is one of the few Dioscorea species that grows well in temperate regions and has been proposed as a climate-resilient crop to enhance food security in Europe. However, the fragile, club-like tubers are unsuitable for mechanical harvesting, which is facilitated by shorter and thicker storage organs. Brassinosteroids (BRs) play a key role in plant cell division, cell elongation and proliferation, as well as in the gravitropic response. We collected RNA-Seq data from the head, middle and tip of two tuber shape variants: F60 (long, thin) and F2000 (short, thick). Comparative transcriptome analysis of F60 vs. F2000 revealed 30,229 differentially expressed genes (DEGs), 1,393 of which were differentially expressed in the growing tip. Several DEGs are involved in steroid/BR biosynthesis or signaling, or may be regulated by BRs. The quantification of endogenous BRs revealed higher levels of castasterone (CS), 28-norCS, 28-homoCS and brassinolide in F2000 compared to F60 tubers. The highest BR levels were detected in the growing tip, and CS was the most abundant (439.6 ± 196.41 pmol/g in F2000 and 365.6 ± 112.78 pmol/g in F60). Exogenous 24-epi-brassinolide (epi-BL) treatment (20 nM) in an aeroponic system significantly increased the width-to-length ratio (0.045 ± 0.002) compared to the mock-treated plants (0.03 ± 0.002) after 7 weeks, indicating that exogenous epi-BL produces shorter and thicker tubers. In this study we demonstrate the role of BRs in D. polystachya tuber shape, providing insight into the role of plant hormones in yam storage organ development. We found that BRs can influence tuber shape in Chinese yam by regulating the expression of genes involved cell expansion. Our data can help to improve the efficiency of Chinese yam cultivation, which could provide an alternative food source and thus contribute to future food security in Europe.

【 授权许可】

Unknown   
Copyright © 2023 Riekötter, Oklestkova, Muth, Twyman and Epping.