Heat in Wheat: Exploit Reverse Genetic Techniques to Discover New Alleles Within the Triticum durum sHsp26 Family

Abstract

Wheat breeding nowadays must address producers and consumers' desire. According to the last FAO report, a dramatic decrease in wheat production is expected in the next decades mainly due to the upcoming climate change. The identification of the processes which are triggered by heat stress and how thermotolerance develops in wheat is an active research topic. Genomic approach may help wheat breeding since it allows direct study on the genotype and relationship with the phenotype. Here the isolation and characterization of four members of the chloroplast-localized small heat shock proteins (sHSP) encoded by the Hsp26 gene family is reported. Furthermore, two high throughput TILLING (Targeting Induced Local Lesions In Genomes) approaches in vivo and in silico were used for the identification of new alleles within this family. Small heat shock proteins are known to prevent the irreversible aggregation of misfolded proteins and contribute to the acquisition of thermotolerance. Chloroplast-localized sHSPs protect the photosynthetic machinery during episodes of high temperature stress. The modulation of the newly discovered genes within the sHsp26 family has been analyzed in vivo and by the ExpVIP platform widening the abiotic stress analysis; and their involvement in the heat stress response has been demonstrated. In addition, in this study a total of 50 TILLING mutant lines have been identified. A set of KASP (Kompetitive Allele Specific PCR) markers was also developed to follow the specific mutations in the ongoing backcrosses, applicable to high throughput genotyping approaches and usable in marker assisted selection breeding programs.

Can High Throughput Phenotyping Help Food Security in the Mediterranean Area?

“…High-throughput phenotyping (HTP) has unlocked new perspectives for non-destructive phenotyping of large populations over time (Singh et al, 2016). It employs the acquisition of digital phenotypic traits by means of sensors, typically in the visible spectrum, as well in the near infrared, and in the induced fluorescence domain (Tardieu et al, 2017), to monitor the plants photosynthetic activity (Li et al, 2014; Fahlgren et al, 2015; Perez-Sanz et al, 2017), growth status (Pieruschka and Poorter, 2012; Petrozza et al, 2014) and the overall water content (Chen et al, 2014) as main components of plant response to limited water availability and heat stress (Comastri et al, 2018).…”

Breeding, genetics, and genomics for tolerance against terminal heat in lentil: Current status and future directions

“…In wheat, new alleles belonging to Hsp26 gene family encoding chloroplast‐localized small (s)HSPs have been identified through high throughput Targeting Induced Local Lesions in Genomes (TILLING) approach of reverse genetics. These alleles encode such HSPs that protect the photosynthetic machinery from high temperature stress (Comastri et al, 2018). Therefore, use of this reverse genetic approach can be focused by developing TILLING populations for identification of heat tolerant genes in lentil.…”

“…Candidate genes or ESTs those are involved in heat tolerance can be used to develop functional markers for breeding (Kumar, Gupta, et al, 2018). In wheat, a set of Kompetitive Allele Specific PCR (KASP) markers has been developed from genes encoding chloroplast‐localized sHSPs in order to identify the heat tolerant genes in breeding populations (Comastri et al, 2018). Genome editing is emerging area of genomics for developing the heat tolerant cultivars.…”

Biotechnological and Digital Revolution for Climate-Smart Plant Breeding

“…TILLING by sequencing has been successfully applied to discover allelic variants underlying agronomic traits involved in the response to climate change [107,108]. In particular, TILLING was used to discover new allelic variants in the Hsp26 gene family related to heat stress and thermal tolerance in wheat [109]. Barley mutants were generated by TILLING to study the nucleotide variations in the era1 (enhanced response to ABA1) gene [110], which is differently regulated under drought tolerance in several species including wheat and soybean [111,112].…”