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BACKGROUND: Plant and animal cells possess a ubiquitous protein known as heat shock proteins (HSPs). Hsps were originally described in relation to heat shock and against abiotic and biotic stresses. Heat shock protein was classified in other crops on the bases of single classes or all classes but in Citrus sinensis Hsps groups, classes, subfamilies and members were not classified and characterized up to our knowledge. OBJECTIVES: Present study was focused on the identification and grouping of C. sinensis Hsps (CsHsps) classes, members among classes, their phylogenetic relationship, gene structure, conserved motifs and identification of proteins by using bioinformatics tools and analyses. MATERIALS AND METHODS: Genomic, Peptide and CDS sequences of CsHsps were downloaded from phytozome. MEGA 7 used for the phylogenetic analysis, GSDS for gene structure, UGENE for the multiple sequence alignment and MEME suite for the conserved motif analysis. RESULTS: The genome size of C. sinensis was 367 Mb, Chromosome number (2n)18, having 151 Hsps with six groups CsHsp10, 20, 40, 60,70 and 90. CsHsp20 was the largest group having 54 members, followed by CsHsp60 and CsHsp70 both having 30 members respectively. CONCLUSION: CsHsps members within a class shared more similar gene and protein structure. CsHsp 60, CsHsp 70 and CsHsp90 shared more conserved and similar amino acid pattern. Each class had some important proteins such as Cpn in CsHsp10, Hypothetical proteins in CsHsp20 and 40, Dnak in CsHsp60, Molecular chaperone in CsHsp70 and Hsp90 in CsHsp90. These proteins are produced by cells in response to stresses in citrus. Chaperonins and some hypothetical proteins identified in CsHsps, help in ATP synthesis and protein degradation. This is genome wide analysis and classification sets the groundwork for future investigations to fully characterize functionally the Citrus Hsps families and underscores the relevance of Hsps response to abiotic and biotic stresses in Citrus.
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Since the publication of this paper, it has become apparent that an error was made in the legend to Fig. 3 and the colours referring to occidental and oriental are the wrong way round. The authors apologise for this error, and a correct version of the legend to Fig. 3 is given below.
RESUMO
BACKGROUND AND AIMS: Date palms (Phoenix dactylifera, Arecaceae) are of great economic and ecological value to the oasis agriculture of arid and semi-arid areas. However, despite the availability of a large date palm germplasm spreading from the Atlantic shores to Southern Asia, improvement of the species is being hampered by a lack of information on global genetic diversity and population structure. In order to contribute to the varietal improvement of date palms and to provide new insights on the influence of geographic origins and human activity on the genetic structure of the date palm, this study analysed the diversity of the species. METHODS: Genetic diversity levels and population genetic structure were investigated through the genotyping of a collection of 295 date palm accessions ranging from Mauritania to Pakistan using a set of 18 simple sequence repeat (SSR) markers and a plastid minisatellite. KEY RESULTS: Using a Bayesian clustering approach, the date palm genotypes can be structured into two different gene pools: the first, termed the Eastern pool, consists of accessions from Asia and Djibouti, whilst the second, termed the Western pool, consists of accessions from Africa. These results confirm the existence of two ancient gene pools that have contributed to the current date palm diversity. The presence of admixed genotypes is also noted, which points at gene flows between eastern and western origins, mostly from east to west, following a human-mediated diffusion of the species. CONCLUSIONS: This study assesses the distribution and level of genetic diversity of accessible date palm resources, provides new insights on the geographic origins and genetic history of the cultivated component of this species, and confirms the existence of at least two domestication origins. Furthermore, the strong genetic structure clearly established here is a prerequisite for any breeding programme exploiting the effective polymorphism related to each gene pool.
