Puroindoline (Pina-D1 and Pinb-D1) and waxy (Wx-1) genes in Iranian bread wheat (Triticum aestivum L.) landraces

Abstract

Grain hardness and starch are two of the most important factors that determine the end-use quality of bread wheat (Triticum aestivum L.) grain. The grain hardness and amylose content are controlled by the puroindolines (Pina-D1 and Pinb-D1) genes, located on chromosomes 5D, and waxy (Wx-A1, -B1 and -D1) genes, located on chromosomes 7A, 4A and 7D. A total of 160 Iranian landraces from the Germplasm Bank of the International Maize and Wheat Improvement Center were evaluated for grain hardness using near infrared spectroscopy to predict the particle size index (PSI). In addition, molecular markers were used to evaluate the states of the corresponding genes. Eight accessions were found to have a hard texture (predicted PSI < 45%); however, only two could be explained by null alleles either in Pina-D1 or Pinb-D1. Additionally, 152 accessions had semi-hard textures (predicted PSI range of 45% to 55%). For the Wx gene, only one accession (CWI 67665) showed the null Wx-D1b allele, while two accessions (CWI 67747 and CWI 57684) were null for Wx-B1b. Single nucleotide polymorphism and sequence tag site marker techniques were used. Our findings further indicate the importance of using these landraces for grain quality improvement in breeding programs.

Exploring the End-Use Quality Potential of a Collection of Spanish Bread Wheat Landraces

“…GPC is a parameter that is related to grain quality, but it is not significantly influenced by HMW-Gs subunits composition. We found a negligible correlation between GPC and SDSS (r = 0.074), which is in accordance with some authors [22,64,74], who showed that dough strength is independent of GPC, although the expression of a high-quality genotype requires enough protein content. The genetic components of GPC have been extensively studied in bread wheat [75][76][77][78], but GPC and yield are both largely influenced by environmental conditions (e.g., [79][80][81]).…”

“…In this work, correlations between traits showed a high and negative correlation between GPC and TKW. A negative correlation between both traits has been found in other studies [64]. Traditionally, high-grain-yielding varieties have been associated with lower-quality parameters, mainly because of the inverse relationship between protein content and grain yield [14,15,94].…”

“…Some rare combinations (i.e., 5+12, 2+12*, 12, and 2+10 ) appeared at a low frequency. These combinations have been previously described in other germplasm collections [62][63][64], but this is the first time that they have been reported in Iberian landraces, probably due to the large number of and high diversity in the accessions analyzed here.…”

“…This may be due to the difficult assignment of this glutenin subunit using only standard SDS-PAGE electrophoresis but could also indicate that it is characteristic of Iberian landraces [42]. Regarding the Glu-B1 locus, it is worth noting that Spanish landraces present a high frequency of the subunit pairs 20x+20y and 13+16, whereas these combinations are absent in landraces from other regions of the world [60][61][62][63][64], indicating the specific conservation of these alleles in the Iberian Peninsula. The 13+16 pair has also been described at a high frequency (88%) in Triticum aestivum ssp.…”

Prevalence of Puroindoline Genes and Their Impact on Quality Traits in A Diverse Germplasm of Wheat Genotypes

“…Different studies detected mutation in purindoline (Pina and Pinb) genes using other techniques, i.e. STS-allele-specific markers, cleaved amplified polymorphic sequences (CAPS), SNP assays and pyrosequencing (Maryami, Azimi, Guzman, Dreisigacker, & Najafian, 2020;Przyborowski, Gasparis, Kała, Orczyk, & Nadolska-Orczyk, 2020). A genomic study of puroindoline alleles revealed that the Pina gene could not be expressed in hard textured wheat as exhibiting mutation in the Pina gene.…”