Biology subjects

Galeffi, P.

Publications and source records attributed to Galeffi, P..

2 recordsLinked to original sources

bioRxiv2022

Allele mining, evolutionary genetic analysis of TaHKT1;5 gene and evaluation of salinity stress in selected lines of wheat.

This study reports the novel allelic diversity in HKT 1;5 gene (High Affinity Potassium Transporter) in bread wheat and its phylogenetic relationship among the paralogs/orthologs of in Triticum aestivum and its wild relatives. HKT 1;5 gene is a known and pivotal gene associated with the salinity tolerance in plants upon the discrimination of K+ over Na+ in leaves without change in Na+ concentration in root. This gene was sequenced in a diverse collection of bread wheat, durum wheat, wild relatives, and ditelosomic lines. Sequence analysis in bread wheat led to the identification of four alleles, which could be distinguished by number of SNPs. Sequence comparison between monocot bread wheat and dicot Arabidopsis thaliana revealed that the HKT1;5 gene is conserved at level of exonic regions; however, the presence of transposable elements especially in intronic regions is further intriguing towards evolutionary relatedness. Two paralogous or major alleles observed in Triticum monoccum and Aegilops tauschii were further categorized as sub-alleles based on their SNPs comparison. This gene was absent in T. urartu in accordance with existing evidence, while it was found in A. speltoides (an allelic variant) with a few base pairs insertion in the exon1 region causing a frameshift mutation with an altered amino acids and genomic database mining unveiled additional alleles in this species. Ditelosomic lines with 4DL and 4DS chromosomes revealed a higher similarity with bread and durum wheat respectively. Phylogenetic studies of HKT1;5 orthologs from different Poaceae species revealed the occurrence of five different ortholog groups with taxonomic consistency. Phenotyping based salinity stress experiment distinguished the unknown lines for salinity tolerance and sensitiveness in comparison with known reference lines and possible allelic comparison was made. The salinity stress analysis further revealed that some known drought/heat tolerance lines showed slightly better salinity tolerance with mean values and variability of traits than known saline tolerant wheat line at controlled ambient.

genetics↗

bioRxiv2022

Identification and evolutionary analysis of a Triticeae tribe specific novel non-autonomous DNA transposon in DREB related Dehydration Responsive Factor1 gene.

A non-autonomous DNA transposon was identified in the DRF1 gene, belonging to the DREB gene family, the presence of this element was initially assessed in the Triticum durum DRF1 gene and subsequently it was also identified in Aegilops speltoides and Triticum urartu DRF1 genes. The DRF1 gene consists of four exons and three introns, the transposon carrying core element is inserted between the first and the third introns. Our studies identified inverted repeats, target site duplications and the presence of many internal reverse and direct short tandem and long tandem repeats, that all represent signals of a transposable element. Based on transposon specific sequence and position of the terminal inverted repeats, a possible transposition mechanism was inferred. As the identified transposable element does not possess a sequence coding for a transposase enzyme, it represents a non-autonomous element. The transposon encompasses a core element with two small, transcribed regions (Exon 2 and Exon 3) that are combined by alternative splicing during gene expression and an intron (intron2). A possible role of this non-autonomous DNA transposon in the alternative splicing regulation was investigated by a genomics approach. Divergence time analysis supported the relatively recent evolution of this transposon in Triticeae comparing to other tribes and further there is no footprints or highly disrupted footprints sequence such as TIR, TSD in other earlier evolved Poaceae member species were observed, which revealed the novelty and well-preserved nature of these signals in Triticeae. While other monocots (apart from Poaceae) and dicots, including Arabidopsis thaliana, neither showed this transposon insertion and nor revealed the existence of alternative spliced gene transcripts. In Poaceae members the core element is well preserved with disturbed transposon and transposon signals, while the tribe Triticeae especially wheat, its progenitors have intact DRF1 transposon and its signals.

evolutionary biology↗