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Chenopodium quinoa Willd. is a crop species domesticated over 5000 years ago. This species is highly diverse, with a geographical distribution that covers more than 5000 km from Colombia to Chile, going through a variety of edaphoclimatic conditions. Quinoa grains have great nutritional quality, raising interest at a worldwide level. In this work, by using shotgun proteomics and in silico analysis, we present an overview of mature quinoa seed proteins from a physiological context and considering the process of seed maturation and future seed germination. For this purpose, we selected grains from four contrasting quinoa cultivars (Amarilla de Maranganí, Chadmo, Sajama and Nariño) with different edaphoclimatic and geographical origins. The results give insight on the most important metabolic pathways for mature quinoa seeds including: starch synthesis, protein bodies and lipid bodies composition, reserves and their mobilization, redox homeostasis, and stress related proteins like heat-shock proteins (HSPs) and late embryogenesis abundant proteins (LEAs), as well as evidence for capped and uncapped mRNA translation. LEAs present in our analysis show a specific pattern of expression matching that of other species. Overall, this work presents a complete snapshot of quinoa seeds physiological context, providing a reference point for further studies., Supplementary Information: The online version contains supplementary material available at 10.1007/s12298-023-01295-8., Competing Interests: Conflict of interestAuthors declare no conflict of interests., (© Prof. H.S. Srivastava Foundation for Science and Society 2023, Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)

Paspalum dilatatum (common name dallisgrass), a productive C4 grass native to South America, is an important pasture grass found throughout the temperate warm regions of the world. It is characterized by its tolerance to frost and water stress and a higher forage quality than other C4 forage grasses. P. dilatatum includes tetraploid (2 n = 40), sexual, and pentaploid (2 n = 50) apomictic forms, but is predominantly cultivated in an apomictic monoculture, which implies a high risk that biotic and abiotic stresses could seriously affect the grass productivity. The obtention of reproducible and efficient protocols of regeneration and transformation are valuable tools to obtain genetic modified grasses with improved agronomics traits. In this review, we present the current regeneration and transformation methods of both apomictic and sexual cultivars of P. dilatatum , discuss their strengths and limitations, and focus on the perspectives of genetic modification for producing new generation of forages. The advances in this area of research lead us to consider Paspalum dilatatum as a model species for the molecular improvement of C4 perennial forage species., Competing Interests: LV was employed by company BASF Argentina SA. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The handling editor declared a shared affiliation with one of the authors GS at the time of review., (Copyright © 2022 Schrauf, Voda, Zelada, García, Giordano, Roa, Guitian, Rebori, Ghio, Couso, Castro, Musacchio, Rush, Nagel, Wang, Cogan and Spangenberg.)

Dehydrins (DHNs) are a family of plant proteins that play important roles on abiotic stress tolerance and seed development. They are classified into five structural subgroups: K-, SK-, YK-, YSK-, and KS-DHNs, according to the presence of conserved motifs named K-, Y- and S- segments. We carried out a comparative structural and phylogenetic analysis of these proteins, focusing on the less-studied KS-type DHNs. A search for conserved motifs in DHNs from 56 plant genomes revealed that KS-DHNs possess a unique and highly conserved N-terminal, 15-residue amino acid motif, not previously described. This novel motif, that we named H-segment, is present in DHNs of angiosperms, gymnosperms and lycophytes, suggesting that HKS-DHNs were present in the first vascular plants. Phylogenetic and microsynteny analyses indicate that the five structural subgroups of angiosperm DHNs can be assigned to three groups of orthologue genes, characterized by the presence of the H-, F- or Y- segments. Importantly, the hydrophilin character of DHNs correlate with the phylogenetic origin of the DHNs rather than to the traditional structural subgroups. We propose that angiosperm DHNs can be ultimately subdivided into three orthologous groups, a phylogenetic framework that should help future studies on the evolution and function of this protein family., (© 2021. The Author(s).)

MicroRNAs (miRNAs) are short, single stranded RNA molecules that regulate the stability and translation of messenger RNAs in diverse eukaryotic groups. Several miRNA genes are of ancient origin and have been maintained in the genomes of animal and plant taxa for hundreds of millions of years, playing key roles in development and physiology. In the last decade, genome and small RNA (sRNA) sequencing of several plant species have helped unveil the evolutionary history of land plants. Among these, the fern group (monilophytes) occupies a key phylogenetic position, as it represents the closest extant cousin taxon of seed plants, i.e. gymno- and angiosperms. However, in spite of their evolutionary, economic and ecological importance, no fern genome has been sequenced yet and few genomic resources are available for this group. Here, we sequenced the small RNA fraction of an epiphytic South American fern, Pleopeltis minima (Polypodiaceae), and compared it to plant miRNA databases, allowing for the identification of miRNA families that are shared by all land plants, shared by all vascular plants (tracheophytes) or shared by euphyllophytes (ferns and seed plants) only. Using the recently described transcriptome of another fern, Lygodium japonicum, we also estimated the degree of conservation of fern miRNA targets in relation to other plant groups. Our results pinpoint the origin of several miRNA families in the land plant evolutionary tree with more precision and are a resource for future genomic and functional studies of fern miRNAs.

The Triple Gene Block 1 (TGBp1) protein encoded by the Potato virus X is a multifunctional protein that acts as a suppressor of RNA silencing or facilitates the passage of virus from cell to cell by promoting the plasmodesmata opening. We previously showed that the membrane raft protein StRemorin1.3 is able to impair PVX infection. Here, we show that overexpressed StRemorin1.3 does not impair the silencing suppressor activity of TGBp1, but affects its ability to increase plasmodesmata permeability. A similar effect on plasmodesmata permeability was observed with other movement proteins, suggesting that REM is a general regulator of plasmodesmal size exclusion limit. These results add to our knowledge of the mechanisms underlying the StREM1.3 role in virus infection., (Copyright © 2014. Published by Elsevier B.V.)

Background: Soil is among the most diverse and complex environments in the world. Soil microorganisms play an essential role in biogeochemical cycles and affect plant growth and crop production. However, our knowledge of the relationship between species-assemblies and soil ecosystem processes is still very limited. The aim of this study was to generate a comprehensive metagenomic survey to evaluate the effect of high-input agricultural practices on soil microbial communities., Results: We collected soil samples from three different areas in the Argentinean Pampean region under three different types of land uses and two soil sources (bulk and rhizospheric). We extracted total DNA from all samples and also synthetized cDNA from rhizospheric samples. Using 454-FLX technology, we generated 112 16S ribosomal DNA and 14 16S ribosomal RNA amplicon libraries totaling 1.3 M reads and 36 shotgun metagenome libraries totaling 17.8 million reads (7.7 GB). Our preliminary results suggested that water availability could be the primary driver that defined microbial assemblages over land use and soil source. However, when water was not a limiting resource (annual precipitation >800 mm) land use was a primary driver., Conclusion: This was the first metagenomic study of soil conducted in Argentina and our datasets are among the few large soil datasets publicly available. The detailed analysis of these data will provide a step forward in our understanding of how soil microbiomes respond to high-input agricultural systems, and they will serve as a useful comparison with other soil metagenomic studies worldwide.

The movement protein (MP) TGBp1 of the potexvirus Potato virus X (PVX) is a multifunctional protein required for cell-to-cell movement within the host plant. Recent work on other plant viruses has indicated that MP phosphorylation by host kinases can regulate MP function. In this study, we demonstrate that recombinant and native TGBp1 are phosphorylated by Nicotiana tabacum extracts from both PVX-infected and non-infected leaves. The phosphorylation activity present in plant extracts has distinctive characteristics of casein kinase 2 (CK2): it is inhibited by heparin, stimulated by polylysine, and uses either ATP or GTP as phosphoryl donors. We also demonstrate that TGBp1 is efficiently phosphorylated by recombinant tobacco CK2 alpha subunit and by partially purified tobacco CK2. Phosphopeptide mass mapping reveals that TGBp1 is phosphorylated in Ser-165, which is localized within a CK2 consensus sequence. Our results strongly suggest that a N. tabacum kinase of the CK2 family is involved in TBGp1 phosphorylation during the course of viral infection.

A good candidate antigen to create a therapeutic vaccine against TB is the ESAT-6 protein. Antigens produced in plants have already been successfully used as experimental vaccines, and small single-stranded RNA plant viruses have emerged as promising tools to rapidly express large amounts of foreign proteins in susceptible host plants. Here, we present the expression of ESAT-6 protein in Nicotiana tabacum using a vector based on potato virus X (PVX). The complete ESAT-6 open reading frame is expressed as a fusion protein with the 2A peptide of Foot and Mouth Disease Virus and the amino terminal of the PVX coat protein (CP) (PVXESAT-6). This strategy allows the production of free CP and ESAT-6 as well as fused ESAT-2A-CP to obtain recombinant chimaeric virions expressing ESAT-6 at the surface to be used as particulate antigen in vaccination. ESAT-6 expression was tested in agroinfiltrated tobacco leaves and products of the expected molecular masses corresponding to cleaved CP and ESAT-2A-CP fusion protein were observed, with ESAT-6 yields ranging from 0.5% to 1% of total soluble protein. Our study describes for the first time the expression of the ESAT-6 protein in tobacco plants using a PVX-derived vector. This strategy should serve as a convenient, rapid, low-cost expression system and can also be used for the assessment of ESAT-6 production and function prior to stable plant transformation.

In this paper we demonstrate that the Candida albicans 20S proteasome is in vivo phosphorylated and is a good in vitro substrate (S(0.5) 14nM) of homologous protein kinase CK2 (CK2). We identify alpha6/C2, alpha3/C9, and alpha5/Pup2 proteasome subunits as the main in vivo phosphorylated and in vitro CK2-phosphorylatable proteasome components. In vitro phosphorylation by homologous CK2 holoenzyme occurs only in the presence of polylysine, a characteristic that distinguishes the yeast proteasomes from mammalian proteasomes which are phosphorylated by CK2 in the absence of polycations. The major in vivo phosphate acceptor is the alpha3/C9 subunit, being phosphorylated in serine, both in vivo and in vitro. The phosphopeptides generated by endoproteinase Glu-C digestion from in vivo labeled alpha3/C9 subunit, from in vitro phosphorylation by homologous CK2 holoenzyme, and from the recombinant alpha3/C9 subunit phosphorylated by recombinant human CK2-alpha subunit are identical, suggesting that CK2 is likely responsible for in vivo phosphorylation of this subunit. Direct mutational analysis shows that serine 248 is the residue of the alpha3/C9 subunit phosphorylated by CK2. The in vitro stoichiometry of phosphorylation of the alpha6/C2 and alpha3/C9 proteasome subunits by CK2 can be estimated as 0.7-0.8 and 0.4-0.5 mol of phosphate per mole of subunit, respectively. These results are consistent with the relative abundance of the unphosphorylated and phosphorylated isoforms of these subunits present in the purified 20S proteasome preparation. Our demonstration of phosphorylation of C. albicans proteasome suggests that phosphorylation might be a general mechanism of regulation of proteasome activity.