Triticale and barley microspore embryogenesis induction requires both reactive oxygen species generation and efficient system of antioxidative defence

Iwona Żur,Ewa Dubas,Gabriela Gołębiowska,Ewa Surówka,Sabina Malaga,Anna Nowicka,Monika Krzewska,Katarzyna Juzoń,Przemysław Kopeć,Katarzyna Gawrońska

doi:10.1007/s11240-021-02012-7

Abstract

The effectiveness of microspore embryogenesis (ME) is determined by a complex network of internal and environmental factors. In the present study on triticale and barley, strong positive correlation (r = 0.85) between the generation of hydrogen peroxide (H2O2) and ME effectiveness confirmed the important role of reactive oxygen species in microspore reprogramming. However, for high effectiveness of ME induction, intensive H2O2 generation had to be associated with high activity of antioxidative enzymes, superoxide dismutase and catalase. The strong seasonal effect on the physiological status of microspores revealed in the study suggests a kind of ‘biological clock’ controlling plant reproduction, crucial for microspore viability and embryogenic potential. Although the effect of various modifications of ME-inducing stress tiller pre-treatment was determined mainly by the physiological condition of microspores, at higher stress intensity positive effects induced by antioxidant molecules—reduced glutathione and its precursor, l-2-oxothiazolidine-4-carboxylic acid—were observed. High level of variation in the response to ME-inducing stress tiller pre-treatment was also revealed between the two DH lines of triticale and two cultivars of barley and among microspores isolated from subsequently developed spikes.

Highlights

The population of isolated and in vitro cultured microspores represents a unique, highly advantageous model for studying the mechanisms which determine the phenomenon of plant cell totipotency, dedifferentiation and reprogramming towards embryogenic development (Testillano 2019)
The first visible difference among the studied plant materials was the yield of isolated microspores received after the standardly used LT tiller pre-treatment (21 days at 4 °C, control), calculated as the mean number of microspores isolated per individual spike
No significant difference was detected between doubled haploid (DH) lines of triticale, while 1.3–2.6–fold higher number of microspores was received from a spike of cv

Summary

Introduction

The population of isolated and in vitro cultured microspores represents a unique, highly advantageous model for studying the mechanisms which determine the phenomenon of plant cell totipotency, dedifferentiation and reprogramming towards embryogenic development (Testillano 2019). Recent interest focused on the role of redox control in plant growth and development suggests that the signal triggering microspore reprogramming is associated with the generation of reactive oxygen species (ROS). ROS play a signalling role, informing plants about stress and initiating many defence reactions (Mittler 2017; Schmitt et al 2014, Noctor et al 2018; Mhamdi and van Breusegem 2018). Other ROS species such as singlet oxygen (1O2) and superoxide anion (O2·−) cannot be excluded from the group of potential candidates to play the role of signalling molecules involved in the induction of stress response mechanisms (Schmitt et al 2014; Dietz et al 2016; Noctor et al 2018, Mhamdi and van Breusegem 2018)

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