Modifying Anthocyanins Biosynthesis in Tomato Hairy Roots: A Test Bed for Plant Resistance to Ionizing Radiation and Antioxidant Properties in Space.

Elisabetta Bennici,Eugenio Benvenuto,Francesca Paolini,Alessia Cemmi,Ilaria Di Sarcina,Cornelis Spelt,Aureliano Bombarely,Antonella Del Fiore,Olivia Costantina Demurtas,Riccardo Pagliarello,Silvia Massa,Gianfranco Diretto,Mattijs Bliek,Patrizia De Rossi,Ronald Koes,Francesca Quattrocchio,H Earl Petzold

doi:10.3389/fpls.2022.830931

Abstract

Gene expression manipulation of specific metabolic pathways can be used to obtain bioaccumulation of valuable molecules and desired quality traits in plants. A single-gene approach to impact different traits would be greatly desirable in agrospace applications, where several aspects of plant physiology can be affected, influencing growth. In this work, MicroTom hairy root cultures expressing a MYB-like transcription factor that regulates the biosynthesis of anthocyanins in Petunia hybrida (PhAN4), were considered as a testbed for bio-fortified tomato whole plants aimed at agrospace applications. Ectopic expression of PhAN4 promoted biosynthesis of anthocyanins, allowing to profile 5 major derivatives of delphinidin and petunidin together with pelargonidin and malvidin-based anthocyanins, unusual in tomato. Consistent with PhAN4 features, transcriptomic profiling indicated upregulation of genes correlated to anthocyanin biosynthesis. Interestingly, a transcriptome reprogramming oriented to positive regulation of cell response to biotic, abiotic, and redox stimuli was evidenced. PhAN4 hairy root cultures showed the significant capability to counteract reactive oxygen species (ROS) accumulation and protein misfolding upon high-dose gamma irradiation, which is among the most potent pro-oxidant stress that can be encountered in space. These results may have significance in the engineering of whole tomato plants that can benefit space agriculture.

Highlights

Hairy Roots Generation and Screening. Both 35S:PhAN4 and 35S:GFP-PhAN4 constructs were independently transferred into the miniature tomato genotype MicroTom to generate hairy root cultures
Control HRCs were obtained by transformation with A. rhizogenes not containing PhAN4
While control HRCs grew as unpigmented organ cultures (Figure 1A, left), HRCs generated by 35S:PhAN4 and 35S:GFP-PhAN4 showed purple pigmentation (Figure 1A, right) that may vary among clones

Summary

Introduction

Anthocyanins act as health-promoting and chronic-diseases-preventing molecules, due to antioxidant, anti-inflammatory, anti-proliferative and anti-neurodegenerative functions (Blesso, 2019; Krga and Milenkovic, 2019; Tian et al, 2019; Bendokas et al, 2020; Kalt et al, 2020). Due to these properties, anthocyanins have increasing applications in the food sector and there is growing interested in the design of food crops with improved levels and composition of these antioxidant nutraceuticals. Candidates for the application of technologies aiming to improve both their content in antioxidant nutraceuticals and resistance to biotic and abiotic stresses (Zabel et al, 2015, 2016; Massa et al, 2016; Khodadad et al, 2020)

Methods

Results

Conclusion