Contribution of functional genomics to identify the genetic basis of water‐deficit tolerance in barley and the related molecular mechanisms

Abstract

Drought, a major environmental constraint, has increasing impact on agricultural production. Genetic improvement for maintaining crop productivity in such adverse conditions is a critical challenge for breeders. Barley exhibits a remarkable genetic diversity associated with a widespread geographical distribution in contrasted climates. This diversity, which resides in regional landraces and wild accessions, has been only recently explored using functional genomics. Here, we review the data gained to identify in the barley germplasm collections, candidate genes participating in mechanisms conferring drought tolerance via signalling and protective mechanisms. We particularly focus on genes, for which QTL determination and association genetic‐based mapping methods validate their likely roles in tolerance. Thus, allelic variants coding for transcription factors, heat shock or late embryogenesis proteins, and actors involved in ABA‐signalling pathways, proline biosynthesis or redox regulation, have been characterized in wild and landrace populations, and constitute a solid basis for improving barley drought tolerance. The huge advance in sequencing technology and mass spectrometry, combined with the power of bioinformatics tools, makes it possible to envisage trials including a large number of genotypes to compare their physiological and biochemical features upon water deficit, and simultaneously determine the genetic basis of their differential behaviour. The implementation of such approaches will be powerful to identify promising loci for breeders for improving barley responses to drought.

Overview of Identified Genomic Regions Associated with Various Agronomic and Physiological Traits in Barley under Abiotic Stresses

“…Barley has a tremendous genetic variety, owing to its extensive geographical distribution and climatic range. Only recently has this regional landrace and wild accessions diversity been studied using functional genomics [101]. Over the past two decades, many Wild barley is a major source of genetic variation, and exploitation of this germplasm has been suggested as a means to increase drought tolerance.…”

“…Barley has a tremendous genetic variety, owing to its extensive geographical distribution and climatic range. Only recently has this regional landrace and wild accessions diversity been studied using functional genomics [101]. Over the past two decades, many investigations identified QTLs linked with yield and its related features and physiological factors in scarcely cultivated crops under drought stress [33,102,103].…”

“…Table S2 lists some of the identified QTLs in different barley populations [33,75,[103][104][105][106][107][108][109][110][111][112][113][114][115][116][117][118][119][120][121]. Marok et al [101] evaluated the collected data to identify potential genes involved in signaling and protective mechanisms that confer drought tolerance in barley germplasm lines. With this knowledge, wild and landrace barley populations may be improved for drought tolerance by enhancing transcription factor, heat shock or late embryogenesis protein (HSP) allelic variations, proline biosynthesis, or redox regulation [101].…”

“…Marok et al [101] evaluated the collected data to identify potential genes involved in signaling and protective mechanisms that confer drought tolerance in barley germplasm lines. With this knowledge, wild and landrace barley populations may be improved for drought tolerance by enhancing transcription factor, heat shock or late embryogenesis protein (HSP) allelic variations, proline biosynthesis, or redox regulation [101]. With the capacity of bioinformatics tools and advances in sequencing and mass spectrometry, large-scale trials of genotypes may be planned to evaluate their physiological and biochemical responses to water deprivation while determining the genetic basis of their differences.…”

Spring Barley Hybrids Assessment for Biological and Economic Features Under Drought Conditions of Northern and Central Kazakhstan

“…Drought accounts for more than 80% of losses in agriculture, especially in the crop and livestock sectors, which seriously affects crop plant development in certain phases like seed germination, heading through plant growth to final maturation and harvest, their interaction with the environmental factors, indicating the complexity of plant response to drought is the result of all these factors. Barley, compared with other cereals, adapts well to different drought levels and has different morphological, biochemical, and molecular mechanisms of drought tolerance, yet, the barley response to drought can vary greatly (Kebede et al, 2019;Ali et al, 2021;Mark et al, 2021;Fatemi et al, 2022). In barley, identifying the drought resistance gene (HvMYB1) is an influential discovery in the present era, helping increase the grain yield suffering from the negative impacts of climate change (Chesnokov, 2013;Karmanenko, 2014).…”