Cereal Husks: Versatile Roles in Grain Quality and Seedling Performance

The seed is the fundamental unit of the dispersal of dry, dehiscent fruits, in which the fruit splits open at maturity to allow for seed dispersal. However, dry fruits may be indehiscent and therefore represent the dispersal unit (DU). Cereals possess a one-seeded fruit, whereby the seed coat and the fruit coat are fused together to generate the caryopsis. This caryopsis may be covered by floral bracts to generate two types of DUs, namely florets, whereby the caryopsis is enclosed by the lemma and the palea (e.g., Avenasterilis) or spikelet, whereby the floret(s) is further covered by the glumes (Triticum turgidum var. dicoccoides). Here, we highlight the dead coverings enclosing the caryopsis in cereals, namely the husks as an integral component of the dispersal unit that play multifaceted roles in grain biology. Thus, besides protection and dispersal means, the husks function as a rich maternal supply of proteins and metabolites for enhancing growth and development, combat potential pathogens as well as confer tolerance to abiotic stresses. These attributes might have broad implications for crop performance, plant population dynamics and diversity in ecological systems, and for conservation of genetic resources in seed banks.

Transcriptional Regulation of Metabolic and Cellular Processes in Durum Wheat (Triticum turgidum subsp. durum) in the Face of Temperature Increasing

The Yaqui Valley, Mexico, has been historically considered as an experimental field for semiarid regions worldwide since temperature is an important constraint affecting durum wheat cultivation. Here, we studied the transcriptional and morphometrical response of durum wheat at an increased temperature (+2 °C) for deciphering molecular mechanisms involved in the thermal adaptation by this crop. The morphometrical assay showed a significant decrease in almost all the evaluated traits (shoot/root length, biovolume index, and dry/shoot weight) except in the dry root weight and the root:shoot ratio. At the transcriptional level, 283 differentially expressed genes (DEGs) were obtained (False Discovery Rate (FDR) ≤ 0.05 and |log2 fold change| ≥ 1.3). From these, functional annotation with MapMan4 and a gene ontology (GO) enrichment analysis with GOSeq were carried out to obtain 27 GO terms significantly enriched (overrepresented FDR ≤ 0.05). Overrepresented and functionally annotated genes belonged to ontologies associated with photosynthetic acclimation, respiration, changes in carbon balance, lipid biosynthesis, the regulation of reactive oxygen species, and the acceleration of physiological progression. These findings are the first insight into the regulation of the mechanism influenced by a temperature increase in durum wheat.

Genetic diversity among queen bee, worker bees and larvae in terms of retrotransposon movements

Objective Honeybee (Apis mellifera L.) is a model organism, contributing significant effect on global ecology by pollination and examining due to its social behaviour. Methods In this study, barley-specific Sukkula and Nikita retrotransposons were analysed using IRAP (Inter-Retrotransposon Amplification Polymorphism) marker technique, and the relationships between retrotransposon movements and development were also investigated in three different colonies of the Caucasian bee (Apis mellifera caucasica). Furthermore, transposon sequences belonging to Apis mellifera, Bombus terrestris, Triticum turgidum and Hordeum vulgare were also examined to figure out evolutionary relationships. Results For this purpose, a queen bee, five worker bees, and five larvae from each colony were studied. Both retrotransposons were found in all samples in three colonies with different polymorphism ratios (0-100% for Nikita and 0-67% for Sukkula). We also determined polymorphisms in queen-worker (0-83% for Nikita, 0-63% for Sukkula), queen-larvae (0-83% for Nikita, 0-43% for Sukkula) and worker-larvae comparisons (0-100% for Nikita, 0-63% for Sukkula) in colonies. Moreover, close relationships among transposons found in plant and insect genomes as a result of in silico evaluations to verify experimental results. Conclusion This work could be one of the first studies to analyse plant-specific retrotransposons’ movements in honeybee genome. Results are expected to understand evolutionary relationships in terms of horizontal transfer of transposons among kingdoms.

EFFECT OF FERTILIZERRS WITH UREASE AND NITRIFICATION INHIBITORS ON DURUM WHEAT CROP ON YIELD AND QUALITY (Triticum turgidum L. subsp. durum)

Conventional agricultural has a significant role in climate change. For this reason, farmers choose more innovative practices such as fertilizers inhibitors. Durum wheat (Triticum turgidum L. subsp. durum) is the most cultivated winter crop in the Mediterranean basin. The scope of this study is to determine the improvement of the fertilizer yield by adding nitrification (DMPSA) and urease (NBPT) inhibitor in urea in durum wheat crop. Meridiano variety was evaluated for one growing period through 2019–2020 under two basic fertilization (20-20-0 and 12-40-0 (+10S +Zn). The experiments were designed according to split-plot design, 2 main plots (basic fertilization) and 7 subplots (top fertilization). The top fertilization were the various urea combination treatments (urea, urea + urease inhibitor thiophosphoric-triamide (NBPT) (UI), urea + nitrogen inhibitor 3,4- dimethylpyrazole succinic (DMPSA) and control. Nitrogen markers, such as nitrogen use efficiency (NUE), nitrogen harvest index and nitrogen agronomic efficiency (NAE) were used to evaluate nitrogen release. The length of the inflorescences was over 20 cm for all fertilizations. Regarding basic fertilization, larger inflorescences were recorded with 12-40-0 (+10S +Zn). The grain protein content and nitrogen were higher by 1-2% under basic basic fertilization 20-20-0. Grain and biomass production were increased with both fertilizers’ inhibitors (NBPT and DMPSA). Between two inhibitors, urease inhibitor (NBPT) yielded higher than DMPSA.

Allelic Variation at Glutenin Loci (Glu-1, Glu-2 and Glu-3) in a Worldwide Durum Wheat Collection and Its Effect on Quality Attributes

Durum wheat grains (Triticum turgidum L. ssp. durum) are the main source for the production of pasta, bread and a variety of products consumed worldwide. The quality of pasta is mainly defined by the rheological properties of gluten, an elastic network in wheat endosperms formed of gliadins and glutenins. In this study, the allelic variation at five glutenin loci was analysed in 196 durum wheat genotypes. Two loci (Glu-A1 and Glu-B1), encoding for high-molecular-weight glutenin subunits (HMW-GS), and three loci (Glu-B2, Glu-A3 and Glu-B3), encoding for low molecular weight glutenin subunits (LMW-GS), were assessed by SDS-PAGE. The SDS-sedimentation test was used and the grain protein content was evaluated. A total of 32 glutenin subunits and 41 glutenin haplotypes were identified. Four novel alleles were detected. Fifteen haplotypes represented 85.7% of glutenin loci variability. Some haplotypes carrying the 7 + 15 and 7 + 22 banding patterns at Glu-B1 showed a high gluten strength similar to those that carried the 7 + 8 or 6 + 8 alleles. A decreasing trend in grain protein content was observed over the last 85 years. Allelic frequencies at the three main loci (Glu-B1, Glu-A3 and Glu-B3) changed over the 1915–2020 period. Gluten strength increased from 1970 to 2020 coinciding with the allelic changes observed. These results offer valuable information for glutenin haplotype-based selection for use in breeding programs.

Magnaporthe oryzae. [Distribution map].

A new distribution map is provided for Magnaporthe oryzae Triticum pathotype (Sordariomycetes: Magnaporthaceae). Hosts: wheat (Triticum aestivum), barley (Hordeum vulgare) and durum wheat (Triticum turgidum subsp. durum). Information is given on the geographical distribution in Africa (Zambia), Asia (Bangladesh) and South America (Argentina, Bolivia, Brazil, Distrito Federal, Goias, Mato Grosso do Sul, Minas Gerais, Parana, Rio Grande do Sul, Sao Paulo, Paraguay).

Genetic variability of some agronomic traits in a collection of wheat (Triticum turgidum L. ssp) genotypes under South Mediterranean growth conditions

Genetic variability of some agronomic traits were investigated in 60 tetraploid wheat accessions (Triticum turgidum L. ssp) under rainfed conditions. The results indicated the presence of sufficient variability for all measured traits.The highest phenotypic and genotypic coefficient of variation was recorded for yield and awn length. High heritability coupled with high genetic advance and high expected response to selection recorded for thousand-grain weight, awn length, and the number of grains per spike. Cluster analysis grouped the 60 wheat genotypes into five clusters. Clusters are relatively formed according to the geographical origin of the genotypes. Cluster III carried entries having the best combinations for all the traits; in which genotypes PI 127106, PI 192658, PI 29051 and PI67343 can represent an important reservoir of useful genes for the development of new wheat cultivars. Thousand-grain weight, biomass, awn length and harvest index could be used as a selection criterion for hybridization programs in the future. Highlights - The genetic variability of 9 traits of 60 wheat varieties was investigated. - There was great variability among wheat genotype for all measured traits. - There were wheat varieties shows highest phenotypic and genotypic coefficient of variation. - Some wheat genotypes may be desired allele reservoirs. - Some traits can be an alternative in wheat selection.