Development of an in vitro Microtuberization and Temporary Immersion Bioreactor System to Evaluate Heat Stress Tolerance in Potatoes (Solanum tuberosum L.).

Sanjeev Gautam,M Isabel Vales,Jorge A Da Silva,Kranthi Mandadi,Megan K Teale,Nora Solis-Gracia

doi:10.3389/fpls.2021.700328

Sanjeev Gautam, M Isabel Vales + Show 4 more

Open Access

https://doi.org/10.3389/fpls.2021.700328

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Abstract

High temperature (heat) stress reduces tuber yield and quality of potatoes. Screening potatoes for heat tolerance is increasingly important, considering the climate change scenario and expansion of potatoes to countries where heat stress is an issue. In vitro screening for tolerance to abiotic stresses offers several advantages, including quick evaluation of numerous genotypes (clones) in reduced space, controlled environmental conditions (temperature and photoperiod), and free from confounding variables inherent to greenhouse and field conditions. In this study, we explored the feasibility of using a temporary immersion bioreactor system for heat tolerance screening of potatoes. We determined the best hormone-free microtuberizing media for this system (MSG with 8% sucrose) to enhance microtuber number and size. Comparisons of microtubers produced at 30°C as heat treatment, with 16°C as normal condition, allowed to identify heat tolerant and susceptible potato clones. The use of bioreactors allowed distinguishing well-formed (non-deformed) from deformed microtubers. Heat stress increased the total biomass of plant tissues in all the clones. However, the effect of heat stress on microtuber number and weight varied among the clones. Incubation at 30°C decreased the weight and number of non-deformed microtubers in all the clones except for Reveille Russet in which the weight of non-deformed microtubers was significantly increased and the count of non-deformed microtubers was not affected. The potato variety Reveille Russet, which was selected under high-temperature field conditions in Texas, had many non-deformed microtubers per explant and the highest microtuber weight among four clones evaluated under heat stress. We described a faster and reliable in vitro microtuberization system for abiotic stress tolerance screening, identified Reveille Russet as a promising heat-tolerant potato variety, and confirmed Russet Burbank and Atlantic as susceptible heat-tolerant checks.

Highlights

Due to global climate change, extreme environmental conditions such as drought and heat have significantly damaged agricultural production and will continue to affect food production worldwide
Five potato clones representing different market classes were used to identify of best tuberization media
Media with Murashige & Skoog with Gamborg’s vitamins (MSG) plus 8% sucrose and without hormones gave the highest number of microtubers per explant, highest microtuber weight, and highest diameter per explant (Table 2) and this media was used for subsequent experiments using bioreactors

Summary

Introduction

Due to global climate change, extreme environmental conditions such as drought and heat have significantly damaged agricultural production and will continue to affect food production worldwide. In potato (Solanum tuberosum L.), heat stress is a significant limitation for production (Lehretz et al, 2019). It has been reported that if temperatures continue to rise in the future, substantial tuber reductions will occur in several potato-producing regions (Hijmans, 2003). Potato is a coolseason crop with optimum temperature for its growth at 20◦C (Ahn et al, 2003). According to Mohabir and John (1988), the optimum temperature for starch formation in tubers is 21.5◦C. Tuberization is reduced at night temperatures above 18◦C and could be absent beyond 25◦C (Bushnell, 1927) even though potato plants can tolerate day temperatures of about 32◦C without significant loss in total biomass production (Minhas et al, 2006)

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