A year of genomic surveillance reveals how the SARS-CoV-2 pandemic unfolded in Africa

In semiarid Mediterranean agroecosystems, drought and salinity are the main abiotic stresses hampering wheat productivity and yield instability. Abscisic acid, stress, and ripening (ASR) are small plant proteins and play important roles in different biological processes. In the present study, the TtASR1 gene was isolated and characterized for the first time from durum wheat (Tritucum turgidum L. subsp. durum). TtASR1 is a small gene, about 684 bp long, located on chromosome 4AL, encoding a protein of 136 amino acid residues consisting of a histidine-rich N terminus and C-terminal conserved ABA-WDS domain (Pfam PF02496). Our results showed that TtASR1 protein could function as a chaperone-like protein and improve the viability of E. coli under heat and cold stress and increase the Saccharomyces cerevisiae tolerance under salt and osmotic stress. Transcript expression patterns of TtASR1 revealed that ASRs play important roles in abiotic stress responses in diverse organs. Indeed, TtASR1 was upregulated in leaves by different developmental (ABA) and environmental signals (PEG, salt). In cv. Mahmoudi (salt-tolerant Tunisian durum landraces) roots, TtASR1 was upregulated by salt stress, while it was downregulated in cv. Azizi (salt-sensitive Tunisian durum landraces), supporting the implication of this gene in the salt tolerance mechanism. Taken together and after validation in the plant system, the TtASR1 gene may provide a potential functional marker for marker-assisted selection in a durum wheat breeding program for salt tolerance.

WRKY transcription factors belong to a large family of plant transcriptional regulators whose members have been reported to be involved in a wide range of biological roles including plant development, adaptation to environmental constraints and response to several diseases. However, little or poor information is available about WRKY's in Citrus. The recent release of completely assembled genomes sequences of Citrus sinensis and Citrus clementina and the availability of ESTs sequences from other citrus species allowed us to perform a genome survey for Citrus WRKY proteins. In the present study, we identified 100 WRKY members from C. sinensis (51), C. clementina (48) and Citrus unshiu (1), and analyzed their chromosomal distribution, gene structure, gene duplication, syntenic relation and phylogenetic analysis. A phylogenetic tree of 100 Citrus WRKY sequences with their orthologs from Arabidopsis has distinguished seven groups. The CsWRKY genes were distributed across all ten sweet orange chromosomes. A comprehensive approach and an integrative analysis of Citrus WRKY gene expression revealed variable profiles of expression within tissues and stress conditions indicating functional diversification. Thus, candidate Citrus WRKY genes have been proposed as potentially involved in fruit acidification, essential oil biosynthesis and abiotic/biotic stress tolerance. Our results provided essential prerequisites for further WRKY genes cloning and functional analysis with an aim of citrus crop improvement.