Stress-induced expression of IPT gene in transgenic wheat reduces grain yield penalty under drought

Ailin Beznec,Paula Faccio,Leonor G Abeledo,Cecilia Decima Oneto,Matías Elizondo,Daniel J Miralles,María De Belén Garibotto,Ezequiel Bossio,Antonio Díaz Paleo,Germán Gonzalez,Berta Llorente,Dalia Lewi,Mónica Ruíz,Federico Moreyra,Eduardo Blumwald

doi:10.1186/s43141-021-00171-w

Abstract

BackgroundThe heterologous expression of isopentenyl transferase (IPT) under the transcriptional control of the senescence-associated receptor-like kinase (SARK) promoter delayed cellular senescence and, through it, increased drought tolerance in plants. To evaluate the effect of pSARK::IPT expression in bread wheat, six independent transgenic events were obtained through the biolistic method and evaluated transgene expression, phenology, grain yield and physiological biomass components in plants grown under both drought and well-irrigating conditions. Experiments were performed at different levels: (i) pots and (ii) microplots inside a biosafety greenhouse, as well as under (iii) field conditions. ResultsTwo transgenic events, called TR1 and TR4, outperformed the wild-type control under drought conditions. Transgenic plants showed higher yield under both greenhouse and field conditions, which was positively correlated to grain number (given by more spikes and grains per spike) than wild type. Interestingly, this yield advantage of the transgenic events was observed under both drought and well-watered conditions. ConclusionsThe results obtained allow us to conclude that the SARK promoter-regulated expression of the IPT gene in bread wheat not only reduced the yield penalty produced by water stress but also led to improved productivity under well-watered conditions.

Highlights

The heterologous expression of isopentenyl transferase (IPT) under the transcriptional control of the senescence-associated receptor-like kinase (SARK) promoter delayed cellular senescence and, through it, increased drought tolerance in plants
In cereal crops, abiotic stresses as water deficit, high temperatures, and salinity are the main causes of yield losses
The insertion of the pSARK::IPT construct was confirmed by the amplification of the 384-bp and 643-bp PCR fragments of the IPT and Phosphinothricin acetyltransferase (BAR) genes, respectively (Fig. 2I (a, b))

Summary

Introduction

The heterologous expression of isopentenyl transferase (IPT) under the transcriptional control of the senescence-associated receptor-like kinase (SARK) promoter delayed cellular senescence and, through it, increased drought tolerance in plants. To evaluate the effect of pSARK::IPT expression in bread wheat, six independent transgenic events were obtained through the biolistic method and evaluated transgene expression, phenology, grain yield and physiological biomass components in plants grown under both drought and well-irrigating conditions. From 1980 to 2015, 21% of the reductions in Plants have developed multiple adaptive mechanisms to grow under water stress Some of these mechanisms are stomatal closure, changes in the concentration of plant growth regulators, reduction of vegetative growth, decrease in the aerial/root partitioning ratio, and leaf senescence [7–9]. Most of these strategies lead to a reduction in biomass accumulation and yield [10]. The yield is defined during the whole cycle, the period from flag-leaf appearance up to 1 week immediately after anthesis is crucial for yield determination and this period is called the “critical period.”

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