Overexpression of IbFAD8 Enhances the Low-Temperature Storage Ability and Alpha-Linolenic Acid Content of Sweetpotato Tuberous Roots.

Chan-Ju Lee,Sang-Soo Kwak,Sul-U Park,Hyun Jo,So-Eun Kim,Chang Yoon Ji,Jeong-Dong Lee,Ye-Hoon Lim,Ho Soo Kim,Ung-Han Yoon

doi:10.3389/fpls.2021.764100

Abstract

Sweetpotato is an emerging food crop that ensures food and nutrition security in the face of climate change. Alpha-linoleic acid (ALA) is one of the key factors affecting plant stress tolerance and is also an essential nutrient in humans. In plants, fatty acid desaturase 8 (FAD8) synthesizes ALA from linoleic acid (LA). Previously, we identified the cold-induced IbFAD8 gene from RNA-seq of sweetpotato tuberous roots stored at low-temperature. In this study, we investigated the effect of IbFAD8 on the low-temperature storage ability and ALA content of the tuberous roots of sweetpotato. Transgenic sweetpotato plants overexpressing IbFAD8 (TF plants) exhibited increased cold and drought stress tolerance and enhanced heat stress susceptibility compared with non-transgenic (NT) plants. The ALA content of the tuberous roots of TF plants (0.19 g/100 g DW) was ca. 3.8-fold higher than that of NT plants (0.05 g/100 g DW), resulting in 8–9-fold increase in the ALA/LA ratio in TF plants. Furthermore, tuberous roots of TF plants showed better low-temperature storage ability compared with NT plants. These results indicate that IbFAD8 is a valuable candidate gene for increasing the ALA content, environmental stress tolerance, and low-temperature storage ability of sweetpotato tuberous roots via molecular breeding.

Highlights

The ongoing global climate change threatens crop productivity by affecting plant physiological processes and reducing plant biomass (Aryal et al, 2019)
Tuberous roots of TF plants displayed enhanced low-temperature storage ability compared with those of NT plans. These results suggest that IbFAD8 is a highly valuable gene that could be used for the molecular breeding of sweetpotato genotypes with high Alpha-linoleic acid (ALA) contents that would be suitable for cultivation in high-latitude regions
To determine the subcellular localization of IbFAD8, a translational fusion of IbFAD8 with the green fluorescent protein (GFP) gene was transiently expressed in tobacco (Nicotiana benthamiana) leaves

Summary

Introduction

The ongoing global climate change threatens crop productivity by affecting plant physiological processes and reducing plant biomass (Aryal et al, 2019). To avoid food shortages in the future, the development of stress tolerant and high yielding crops is critical. Sweetpotato (Ipomoea batatas [L.] Lam) is regarded as the fifth most important starch-rich crop that shows high potential for achieving the sustainable development goals, despite the ongoing climate change, owing to its high stress tolerance and ease of cultivation (Food and Agriculture Organization [FAO], 2020; Heider et al, 2021). Sweetpotato shows superior carbohydrate production capability than other starch-rich crops, such as wheat (Triticum aestivum), corn (Zea mays), potato (Solanum tuberosum), and cassava (Manihot esculenta), when grown on marginal lands (Ziska et al, 2009). Sweetpotato has emerged as an important food crop that ensures global food and nutrition security in the face of climate crisis (Kwak, 2019)

Methods

Results

Conclusion