Biology subjects

Pasquariello, M.

Publications and source records attributed to Pasquariello, M..

4 recordsLinked to original sources

bioRxiv2026

Wheat mutants lacking Starch Synthase 1 have altered starch composition and cell wall content

Starch Synthase 1 (SS1) participates in the synthesis of amylopectin. To determine its role in hexaploid bread wheat, we selected and combined TILLING mutations for each homoeologue to create two independent SS1-deficient lines. The lines, which have different combinations of ss1 mutations, both lacked SS1 protein. Both lines exhibited mild but significant changes to starch phenotype, including fewer short amylopectin chains, a slight increase in B-type starch granules and a modest increase in amylose content. Lack of SS1 also led to changes in the thermal properties of starch measured by differential scanning calorimetry including reduced enthalpy, and increased gelatinization temperature. Despite the changes to starch properties, the starch contents of the mutant lines compared to wild types were within the normal range, as were grain weight and protein content. However, the concentration of total- and water-extractable arabinoxylan, and MLG, were increased in white flour compared to wild-type controls. HighlightLack of SS1 led to changes in starch molecular structure and thermal behavior. Starch content and grain weight were normal but cell wall polysaccharides in white flour were increased.

plant biology↗

bioRxiv2025

Mutations in HOMEOBOX DOMAIN-2 improve grain protein content in wheat without significantly affecting grain yield and senescence

MicroRNA-resistant alleles of HOMEOBOX DOMAIN-2 (HB-2) were recently reported to improve grain protein content (GPC) in wheat by modifying vascular development in stems to increase amino acid distribution to grain. However, it is not known if these alleles increase GPC at the expense of other physiologically important traits, such as senescence and yield-component traits. Here, we evaluated the effects of mutations in HB-2 on grain yield and nitrogen (N)-use efficiency as well as senescence and plant architecture in multi-environment glasshouse and field experiments. In glasshouse experiments, the mutations in HB-2 moderately improved GPC irrespective of N supply and without accelerating senescence or decreasing grain number or weight compared to the wildtype spring wheat cv. Cadenza. The trait analysis indicated mutant plants were more tolerant of N limitation in terms of above-ground N reduction compared to the wild type. The expression of all HB-2 homeologues increased in spikes at the lemma primordium stage in response to N limitation, indicating the later GPC increase could be a result of enhanced N sink strength determined during early development, rather than processes caused by direct changes in HB-2 expression in the grain. In field experiments, the introgression of HB-2 alleles into Australian elite spring wheat cultivars significantly improved GPC without compromising grain yield. The outcomes of this study support the introduction of miRNA-resistant HB-2 alleles, with a preference to HB-A2, into commercial wheat for improving grain quality without a yield penalty.

plant biology↗

bioRxiv2025

Spatial transcriptomics identifies distinct domains regulating yield-related traits of the wheat ear

Cereal inflorescences are complex, highly ordered structures composed of grain-producing florets that form within specialised branches called spikelets. The spikelets of wheat are arranged in two alternating rows along a central rachis, in a pattern determined during early reproductive development. While several genes that control spikelet development have been identified, the molecular processes that regulate their morphology and the formation of supporting structures, such as meristems and the rachis, remain poorly understood. Here, we used spatial transcriptomics to investigate the dynamic transcriptional landscape of a wheat inflorescence during spikelet development. We identified two spatially distinct regions that regulate spikelet architecture, including a primordium region characterised by RAMOSA2 activity, and a boundary region that expresses ALOG1 and known regulators of bract suppression. Developmental assays indicate that spikelets differentiate from meristematic regions, which is accompanied by formation of central vascular regions of the rachis and inflorescence base that express genes controlling spikelet number. The combined spatial transcriptome and genetic data reveal key regulators of spikelet development, including target genes for improving spikelet number and yield.

plant biology↗

bioRxiv2022

Development of a high-throughput starch digestibility assay reveals wide variation among the A. E. Watkins wheat landrace collection

Breeding for less digestible starch in wheat can improve the health impact of bread and other wheat foods. Based on an established in vitro starch digestibility assay by Edwards et al. (2019) we developed a high-throughput assay to measure starch digestibility in hydrothermally processed samples for use in forward genetic approaches. Digestibility of purified starch from maize and wheat was measured using both methods and produced comparable results. Using the high-throughput assay, we estimated starch digestibility of 118 wheat landraces from the core Watkins collection and found wide variation across lines and elite UK varieties, (20% to 40% and 31% to 44% starch digested after 90 minutes respectively). Sieved flour fractions and purified starch for selected lines showed altered starch digestibility profiles compared with wholemeal flour, suggesting that matrix properties of flour rather than intrinsic properties of starch granules conferred the low starch digestibility observed.

biochemistry↗