Genome-wide association study identifies loci and candidate genes for RVA parameters in wheat (Triticum aestivum L.).

The gelatinization and retrogradation characteristics of wheat starch affect the eating quality of Chinese-style food. Rapid Visco Analyzer (RVA) parameters have been widely used as important indicators to evaluate and improve the quality of wheat starch. However, the genetic basis of RVA parameters remains to be further explored. In the present study, a natural population was genotyped using 90K single nucleotide polymorphism (SNP) arrays, and the RVA parameters of this population grown in five environments were evaluated. The results showed that 22,068 high-quality SNP markers were identified and distributed unequally on the chromosomes. According to the genetic distance, 214 wheat materials were divided into four groups. Except for the pasting temperature (PTT), six parameters followed a normal distribution. Based on the general linear model, 969 significant association SNPs were detected by genome-wide association studies (GWAS), and chromosomes 7A and 2B had the most associated SNPs. Breakdown viscosity (BV) was associated with the most SNPs (n = 238), followed by PTT (n = 186), peak viscosity (PV; n = 156), trough viscosity (TV; n = 127), and final viscosity (FV; n = 126). According to the average linkage disequilibrium (LD), 33 stable quantitative trait loci (QTLs) were identified for single parameters in multiple environments, of which 12 were associated with BV, followed by peak time (PT; n = 8) and PTT (n = 7). On the other hand, 67 pleiotropic QTLs were identified for multiple parameters. Three candidate genes-TasbeIIa, TasbeI, and TassIIa-were screened for phenotyping analysis. The grain width and the weight of the TasbeIIa and TaSSIIa knockout (KO) lines were significantly lower than those of the TasbeI KO lines and the control (CK). The KO lines had smaller endosperm cells, smaller A-type starch granules, and higher amylose content. The TasbeI KO lines showed normal RVA curves, while the TasbeIIa KO lines showed flat curves. However, the TaSSIIa lines failed to paste under the RVA temperatures. Conclusively, the SNPs/QTLs significantly associated with the RVA parameters and genetic resources with novel haplotypes could be used to improve the quality of wheat starch.

Infrared Thermography Monitoring of Durum and Common Wheat for Adaptability Assessing and Yield Performance Prediction.

Wheat is one of the most cultivated cereals thanks to both its nutritional value and its versatility to technological transformation. Nevertheless, the growth and yield of wheat, as well as of the other food crops, can be strongly limited by many abiotic and biotic stress factors. To face this need, new methodological approaches are required to optimize wheat cultivation from both a qualitative and quantitative point of view. In this context, crop analysis based on imaging techniques has become an important tool in agriculture. Thermography is an appealing method that represents an outstanding approach in crop monitoring, as it is well suited to the emerging needs of the precision agriculture management strategies. In this work, we performed an on-field infrared monitoring of several durum and common wheat varieties to evaluate their adaptability to the internal Mediterranean area chosen for cultivation. Two new indices based on the thermal data useful to estimate the agronomical response of wheat subjected to natural stress conditions during different phenological stages of growth have been introduced. The comparison with some productive parameters collected at harvest highlighted the correlation of the indices with the wheat yield (ranging between p < 0.001 and p < 0.05), providing interesting information for their early prediction.

Assessment of the genetic diversity of the alleles of gliadin-coding loci in common wheat (Triticum aestivum L.) collections in Kazakhstan and Russia.

The study of genetic resources using prolamin polymorphism in wheat cultivars from countries with different climatic conditions makes it possible to identify and trace the preference for the selection of the alleles of gliadine-coding loci characteristic of specific conditions. The aim of the study was to determine the "gliadin profile" of the collection of common wheat (Triticum aestivum L.) from breeding centers in Russia and Kazakhstan by studying the genetic diversity of allelic variants of gliadin-coding loci. Intrapopulation (µ ± Sµ) and genetic (H) diversity, the proportion of rare alleles (h ± Sh), identity criterion (I) and genetic similarity (r) of common wheat from eight breeding centers in Russia and Kazakhstan have been calculated. It has been ascertained that the samples of common wheat bred in Kostanay region (Karabalyk Agricultural Experimental Station, Kazakhstan) and Chelyabinsk region (Chelyabinsk Research Institute of Agriculture, Russia) had the highest intrapopulation diversity of gliadin alleles. The proportion of rare alleles (h) at Gli-B1 and Gli-D1 loci was the highest in the wheat cultivars bred by the Federal Center of Agriculture Research of the South-East Region (Saratov region, Russia), which is explained by a high frequency of occurrence of Gli-B1e (86 %) and Gli-D1a (89.9 %) alleles. Based on identity criterion (I), the studied samples of common wheat from different regions of Kazakhstan and Russia have differences in gliadin-coding loci. The highest value of I = 619.0 was found when comparing wheat samples originated from Kostanay and Saratov regions, and the lowest I = 114.4, for wheat cultivars from Tyumen and Chelyabinsk regions. Some region-specific gliadin alleles in wheat samples have been identified. A combination of Gli-A1f, Gli-B1e and Gli-Da alleles has been identified in the majority of wheat samples from Kazakhstan and Russia. Alleles (Gli-A1f, Gli-A1i, Gli-A1m, Gli-A1o, Gli-B1e, Gli-D1a, Gli-D1f, Gli-A2q, Gli-B2o, and Gli-D2a) turned out to be characteristic and were found with varying frequency in wheat cultivars in eight regions of Russia and Kazakhstan. The highest intravarietal polymorphism (51.1 %) was observed in wheat cultivars bred in Omsk region (Russia) and the lowest (16.6 %), in Pavlodar region (Kazakhstan). On the basis of the allele frequencies, a "gliadin profile" of wheat from various regions and breeding institutions of Russia and Kazakhstan was compiled, which can be used for the selection of parent pairs in the breeding process, the control of cultivars during reproduction, as well as for assessing varietal purity.

Update on the Basic Understanding of Fusarium graminearum Virulence Factors in Common Wheat Research.

Wheat is one of the most important food crops, both in China and worldwide. Wheat production is facing extreme stresses posed by different diseases, including Fusarium head blight (FHB), which has recently become an increasingly serious concerns. FHB is one of the most significant and destructive diseases affecting wheat crops all over the world. Recent advancements in genomic tools provide a new avenue for the study of virulence factors in relation to the host plants. The current review focuses on recent progress in the study of different strains of Fusarium infection. The presence of genome-wide repeat-induced point (RIP) mutations causes genomic mutations, eventually leading to host plant susceptibility against Fusarium invasion. Furthermore, effector proteins disrupt the host plant resistance mechanism. In this study, we proposed systematic modification of the host genome using modern biological tools to facilitate plant resistance against foreign invasion. We also suggested a number of scientific strategies, such as gene cloning, developing more powerful functional markers, and using haplotype marker-assisted selection, to further improve FHB resistance and associated breeding methods.

Disomic chromosome 3R(3B) substitution causes a complex of meiotic abnormalities in bread wheat Triticum aestivum L.

Triticum aestivum L. lines introgressed with alien chromosomes create a new genetic background that changes the gene expression of both wheat and donor chromosomes. The genes involved in meiosis regulation are localized on wheat chromosome 3B. The purpose of the present study was to investigate the effect of wheat chromosome 3B substituted with homoeologous rye chromosome 3R on meiosis regulation in disomically substituted wheat line 3R(3B). Employing immunostaining with antibodies against microtubule protein, α-tubulin, and the centromere-specific histone (CENH3), as well as FISH, we analyzed microtubule cytoskeleton dynamics and wheat and rye 3R chromosomes behavior in 3R(3B) (Triticum aestivum L. variety Saratovskaya 29 × Secale cereale L. variety Onokhoiskaya) meiosis. The results revealed a set of abnormalities in the microtubule dynamics and chromosome behavior in both first and second divisions. A feature of metaphase I in 3R(3B) was a decrease in the chiasmata number compared with variety Saratovskaya 29, 34.9 ± 0.62 and 41.92 ± 0.38, respectively. Rye homologs 3R in 13.18 % of meiocytes did not form bivalents. Chromosomes were characterized by varying degrees of compaction; 53.33 ± 14.62 cells lacked a metaphase plate. Disturbances were found in microtubule nucleation at the bivalent kinetochores and in their convergence at the spindle division poles. An important feature of meiosis was the asynchronous chromosome behavior in the second division and dyads at the telophase II in 8-13 % of meiocytes, depending on the anther studied. Considering the 3R(3B) meiotic phenotype, chromosome 3B contains the genes involved in the regulation of meiotic division, and substituting 3B3B chromosomes with rye 3R3R does not compensate for their absence.

Analysis of the Effects of the Vrn-1 and Ppd-1 Alleles on Adaptive and Agronomic Traits in Common Wheat (Triticum aestivum L.).

Wheat heading time is primarily governed by two loci: VRN-1 (response to vernalization) and PPD-1 (response to photoperiod). Five sets of near-isogenic lines (NILs) were studied with the aim of investigating the effect of the aforementioned genes on wheat vegetative period duration and 14 yield-related traits. Every NIL was sown in the hydroponic greenhouse of the Institute of Cytology and Genetics, SB RAS. To assess their allelic composition at the VRN-1 and PPD-1 loci, molecular markers were used. It was shown that HT in plants with the Vrn-A1vrn-B1vrn-D1 genotype was reduced by 29 and 21 days (p < 0.001) in comparison to HT in plants with the vrn-A1Vrn-B1vrn-D1 and the vrn-A1vrn-B1Vrn-D1 genotypes, respectively. In our study, we noticed a decrease in spike length as well as spikelet number per spike parameter for some NIL carriers of the Vrn-A1a allele in comparison to carriers of the Vrn-B1 allele. PCA revealed three first principal components (PC), together explaining more than 70% of the data variance. Among the studied genetic traits, the Vrn-A1a and Ppd-D1a alleles showed significant correlations with PCs. Regarding genetic components, significant correlations were calculated between PC3 and Ppd-B1a (-0.26, p < 0.05) and Vrn-B1 (0.57, p < 0.05) alleles. Thus, the presence of the Vrn-A1a allele affects heading time, while Ppd-D1a is associated with plant height reduction.

Studying a collection of common-wheat varieties for leaf rust resistance, crop yield and grain quality in the environmental conditions of Novosibirsk region.

The relationship between a variety's genotype, environmental conditions and phytopathogenic load are the key factors contributing to high yields that should be taken into account in selecting donors for resistance and high manifestation of valuable traits. The study of leaf rust resistance in 49 common wheat varieties was carried out in the field against the natural pathogen background and under laboratory conditions using single-pustule isolates with virulence to Lr9 and Lr24. It has been shown that the varieties carrying alien genes Lr6Agi2 (Tulaikovskaya 10) and Lr6Agi1 (Voevoda) were resistant to leaf rust infection both in the field and in the laboratory. Varieties KWS Buran, KWS Akvilon, KW 240-3-13, and Etyud producing crop yields from 417 to 514 g/m2 comparable to the best standard variety Sibirskaya 17 can be reasonably used as Lr24 resistance gene donors under West Siberian conditions. Omskaya 44 variety showing crop yield of 440g/m2 can be used as a donor for Lr19 and partially effective Lr26. Varieties Tuleevskaya and Altayskaya 110 with Lr9 in their genomes are recommended for the development of resistance gene-pyramided genotypes. The highest protein and gluten contents were observed in the CS2A/2M sample, while KWS Buran, Altayskaya 110, Volgouralskaya, and KWS Akvilon showed the lowest values. Varieties CS2A/2M, Tulaikovskaya 10, Pavon, and Tuleevskaya were ranked the highest in micro- (Cu, Mn, Zn, Fe) and macronutrient (Ca, Mg, K) contents among the common wheat samples from the collection, while the lowest values for most elements were observed in KWS Buran, Novosibirskaya 15, and Volgouralskaya. Winter varieties demonstrating leaf rust resistance against the infectious background typically carry adult plant resistance genes (Lr34, Lr12, and Lr13), particularly combined with the juvenile Lr26 gene. The presence of Lr41 in a winter type line (KS 93 U 62) allowed it to maintain resistance against a leaf rust pathogen clone kLr24, despite the presence of Lr24 in the genotype. Varieties Doka and Cheshskaya 17 may act as donors of resistance genes Lr26 + Lr34 and Lr9 + Lr12 + Lr13 + Lr34, as well as sources of dwarfing without losses in winter hardiness and yield under West Siberian conditions.

The effect of salicylic and jasmonic acids on the activity of SnAGO genes in the fungus Stagonospora nodorum Berk. in in vitro culture and during infection of wheat plants.

RNA interference is a gene silencing mechanism that plays an important role in genetic regulation in a number of eukaryotes. Argonaute (AGO) proteins are central to the complex RNA interference system. However, their role in this mechanism, both in the host plant organism and in the pathogen, has not yet been fully elucidated. In this work, we identified and phylogenetically analyzed the SnAGO1, SnAGO2, SnAGO3, and SnAGO18 genes of the pathogenic fungus Stagonospora nodorum Berk., and analyzed their expression under conditions of infection of plants with varying degrees of resistance to the pathogen. The expression level against the background of plant immunization with the resistance inducers salicylic and jasmonic acids was assessed. In addition, the activity of these genes in the culture of the fungus in vitro was studied under the direct influence of resistance inducers on the mycelium of the fungus. Earlier activation of the SnAGO genes in in vitro culture under the influence of salicylic and jasmonic acids suggests their sensitivity to it. In an in vivo system, plant immunization to induce the accumulation of pathogen SnAGO transcripts was found. At the same time, the SnAGO genes of the fungus S. nodorum, when interacting with plant cells, reacted depending on the degree of host resistance: the highest level of transcripts in the resistant variety was observed. Thus, our data prove that the SnAGO genes of the fungus S. nodorum effectively interact with the host defense system in direct proportion to the degree of resistance of the latter to the pathogen. It was proposed to use the ratio of the transcriptional activity of the fungal reference gene SnTub to the host TaRLI gene as a marker of disease development in the initial period of the infectious process.

Medición del índice glucémico de 2 variedades de pastas y 2 variedades de arroz / Glycemic index of two varieties of pasta and two varieties of rice

El IG ha sido ampliamente estudiado como un indicador de los efectos fisiológicos de una comida con carbohidratos y es de interés en el manejo y la prevención de la diabetes, las dislipemias y la obesidad. Para medir el índice glucémico (IG) de dos importantes alimentos fuente de carbohidratos se realizó un ensayo con voluntarios siguiendo la metodología recomendada por la Organización Mundial de la Salud (OMS), consistente en realizar mediciones de glucemia capilar al comenzar y a los 15, 30, 45, 60, 90 y 120 minutos de ingerir el alimento en un panel de 9 individuos y calcular el área incremental bajo la curva respecto del mismo ensayo con el alimento control en este caso solución de glucosa al 20% . Se obtuvieron los siguientes resultados: Pasta de sémola de trigo candeal (Triticum durum): 38; Pasta de harina de trigo común (Triticum aestivum): 73; Arroz parboil: 59 y Arroz blanco grano largo: 71. Este ensayo confirma el bajo índice glucémico de las pastas de harina de trigo candeal, es la primera medición para una pasta de harina de trigo común adecuadamente caracterizada y señala los valores de las presentaciones predominantes de arroz en numerosos países, añadiendo una referencia para profesionales y autoridades.

The IG has been extensively studied as an indicator of the physiological effects of a carbohydrate meal with applications in the management and prevention of diabetes, dyslipidemia and obesity. A standard assay was performed to measure the glycemic index ( GI) of two significant sources of carbohydrates following the World Health Organization (WHO) recommended methodology, determining the incremental area under the blood glucose response curve of a 50g carbohydrate portion of the test food compared to the same amount of carbohydrate from a glucose solution by the same subject measured in capillary whole blood before and 15, 30, 45, 60, 90 and 120 minutes after ingestion in a total of 9 subjects. The following results were obtained: Parboil rice: 73, Long Grain White Rice: 59; Pasta of durum wheat (Triticum durum): 71, Pasta of regular flour (Triticum aestivium): 38. This test confirms the low glycemic index of pasta made from durum wheat, and is the first measurement for pasta of common wheat flour properly characterized. It also indicates the values of the prevailing presentations of rice in the region, adding a reference for professionals and authorities.