Genetic basis of drought tolerance during seed germination in barley

Abstract

Drought is one of the harshest abiotic stresses hindering seed germination, plant growth, and crop productivity. A high rate and uniformity of germination under stressful conditions are vital for crop establishment and growth; thus, for productivity. A better understanding of the genetic architecture of seed germination under drought stress is a prerequisite for further increasing yield potential. Barley is considered one of the most abiotic stresses-tolerant cereals. Elucidating the drought tolerance of barley during seed germination would indeed pave the way towards improving the performance of all cereals. However, we still know relatively little about the genetic control of drought tolerance during the seed germination phase. In our study, 218 worldwide spring barley accessions were subjected to PEG-induced drought during seed germination. Induced drought stress "20% PEG" significantly reduced the seed germination parameters and seedling related traits. A genome-wide association scan (GWAS) was used to identify genomic regions associated with our trait of interest. In total, 338 single nucleotide polymorphisms (SNPs) were found to be associated with several traits distributed across seven barley chromosomes, of which 26 genomic regions were associated with candidate genes. The current study found some of the quantitative trait loci (QTL) that have previously been reported to be linked to seed germination-related traits under drought conditions, as well as some new associations. Noteworthy, the identified QTL colocalized with a number of genes (within interval ±0.5 Mbp) that are exclusively distributed on chromosomes 1H, 2H, and 5H. The annotation of these genes in barley shows their roles in drought tolerance through encoding different transcription factors. The function of the identified genes during seed germination was also confirmed by the annotation of their counterparts in Arabidopsis. The current analyses show the power of the GWAS both for identifying putative candidate genes and for improving plant adaptive traits in barley.

Brassica Rapa SR45a Regulates Drought Tolerance via the Alternative Splicing of Target Genes

“…The germination percentage (G%) was calculated after 7 d of incubation at 23 • C in 60% relative humidity with a 16 h photoperiod in a growth chamber. The drought tolerance index (DTI = G% under droughtstress G% under control X 100) of each line was calculated as described previously [25]. Similarly, the heat stress responses of 9-day-old seedlings of OEs, mutants, and controls grown on plates were tested by immersing in a water bath for 35 min at 45 • C. After an 8-d recovery period, the heat stress tolerance was estimated as percentage of seedlings survival under stress conditions.…”

Variability in seed germination of barley cultivars (Hordeum vulgare L.) grown under different nitrogen application rates

“…Reduced biosynthesis of gibberellins during seed germination is related to stress response (Colebrook et al, 2014). The functioning of connection gene hormones is related to germination response, which can be reduced under stress conditions (salt, drought) in sensitive barley cultivars (Emre et al, 2011;Thabet et al, 2018), and the physiological damage to the seed caused by stress can negatively affect seed viability and vigour, depending on genotype (Sun et al, 2007). In addition, the dynamic nature of root tip properties could have a significant impact on drought tolerance (Carter et al, 2019).…”

Genome-wide association and epistatic interactions of flowering time in soybean cultivar

“…A genome-wide association study (GWAS) is one of the promising approaches for the identification of genomic variants responsible for specific phenotypes [1]. With the introduction of high-density marker arrays, GWAS has been actively used in many crop species [2] and has enabled the discovery of single nucleotide polymorphism (SNP) markers associated with numerous agronomic traits [3]: flowering time [4,5], cold tolerance [6], salt tolerance [7,8], drought tolerance [9], disease resistance [10,11], plant height [12,13], leaf architecture [14,15], and seed weight [16,17]. The knowledge of the trait-related SNP markers has served as the genetic basis for the improvement of various traits in crop breeding programs [18].…”