Pedro Darío Zapata

Bio-inoculation of yerba mate seedlings (Ilex paraguariensis St. Hill.) with native plant growth-promoting rhizobacteria: a sustainable alternative to improve crop yield

In this study, the role of native plant growth-promoting rhizobacteria (PGPR) as bio-inoculants was assessed as an alternative to ameliorate Ilex paraguariensis St. Hill. growth in nursery comparing poorer (soil) versus richer (compost) substrates. Twelve rhizospheric strains isolated from yerba mate plantations were evaluated in vitro for their potential as PGPRs. Three isolates, identified as Kosakonia radicincitans YD4, Rhizobium pusense YP3, and Pseudomonas putida YP2, were selected on the basis of their N2 fixation activity, IAA-like compound and siderophore production, and phosphate solubilization. A highly significant positive effect of bio-inoculation with the native isolates was observed in 5-month-old seedlings cultivated in soil. The highest increase was observed in seedlings inoculated with K. radicincitans YD4 with an increase of 183xa0% in the dry shoot weight and a 30xa0% increase in shoot N content. In contrast, in compost, no increment in the dry weight was observed; however, an increase in content in some macronutrients in shoots was observed. Remarkably, when plant biomass was compared between soil and compost, seedlings inoculated with K. radicincitans YD4 in soil produced the highest yields, even though higher yields could be expected in compost due to the richness of this substrate. In conclusion, bio-inoculation of yerba mate seedlings with native PGPR increases the yield of this crop in nursery and could represent a promising sustainable strategy to improve yerba mate growth in low-fertility soils.

Genome Sequence of Kosakonia radicincitans Strain YD4, a Plant Growth-Promoting Rhizobacterium Isolated from Yerba Mate (Ilex paraguariensis St. Hill.)

ABSTRACT Kosakonia radicincitans strain YD4 is a rhizospheric isolate from yerba mate (Ilex paraguariensis St. Hill.) with plant growth-promoting effects on this crop. Genes involved in different plant growth-promoting activities are present in this genome, suggesting its potential as a bioinoculant for yerba mate.

The complete genome of a putative endornavirus identified in yerba mate (Ilex paraguariensis St. Hil.)

We present the first report of a virus infecting the subtropical tree crop yerba mate (Ilex paraguariensis St. Hil.). Total RNA purification, followed by next-generation sequencing, transcripts assembly and annotation, resulted in the identification of a new endornavirus species infecting yerba mate. The complete sequence of the linear dsRNA viral genome is 13,954-nt long, contains a single 13,743xa0nt ORF, and presents a 149xa0nt 5′UTR and a 61xa0nt 3′UTR. The predicted ORF encodes a 4,581xa0aa polypeptide with a UDP-glucose glycosyl-transferase, a capsular polysaccharide synthesis protein, and a RNA-dependent RNA polymerase domain. The name yerba mate endornavirus is proposed for the identified virus. Due to the intriguing peculiarities of this virus family, and the complete lack of the yerba mate virus literature, we consider that the information reported here will be helpful in leading to a new and needed attention to this important topic and crop.

Exploring the Genes of Yerba Mate (Ilex paraguariensis A. St.-Hil.) by NGS and De Novo Transcriptome Assembly

Yerba mate (Ilex paraguariensis A. St.-Hil.) is an important subtropical tree crop cultivated on 326,000 ha in Argentina, Brazil and Paraguay, with a total yield production of more than 1,000,000 t. Yerba mate presents a strong limitation regarding sequence information. The NCBI GenBank lacks an EST database of yerba mate and depicts only 80 DNA sequences, mostly uncharacterized. In this scenario, in order to elucidate the yerba mate gene landscape by means of NGS, we explored and discovered a vast collection of I. paraguariensis transcripts. Total RNA from I. paraguariensis was sequenced by Illumina HiSeq-2000 obtaining 72,031,388 pair-end 100 bp sequences. High quality reads were de novo assembled into 44,907 transcripts encompassing 40 million bases with an estimated coverage of 180X. Multiple sequence analysis allowed us to predict that yerba mate contains ∼32,355 genes and 12,551 gene variants or isoforms. We identified and categorized members of more than 100 metabolic pathways. Overall, we have identified ∼1,000 putative transcription factors, genes involved in heat and oxidative stress, pathogen response, as well as disease resistance and hormone response. We have also identified, based in sequence homology searches, novel transcripts related to osmotic, drought, salinity and cold stress, senescence and early flowering. We have also pinpointed several members of the gene silencing pathway, and characterized the silencing effector Argonaute1. We predicted a diverse supply of putative microRNA precursors involved in developmental processes. We present here the first draft of the transcribed genomes of the yerba mate chloroplast and mitochondrion. The putative sequence and predicted structure of the caffeine synthase of yerba mate is presented. Moreover, we provide a collection of over 10,800 SSR accessible to the scientific community interested in yerba mate genetic improvement. This contribution broadly expands the limited knowledge of yerba mate genes, and is presented as the first genomic resource of this important crop.

Association Between Methylation of SHP-1 Isoform I and SSTR2A Promoter Regions with Breast and Prostate Carcinoma Development

Methylation pattern is presented here for first time as a potential molecular marker of changes on SSTR2A and SHP-1(I) gene promoter related to breast and prostate carcinoma. Our results have shown low concordances with SSTR2A and methylated state in prostate cancer and moderate relationship with unmethylated CpG-27 in breast cancer. We found significant concordances for both cancers and SHP-1(I) unmethylation, and increased HER2 expression and SSTR2A methylation in breast cancer. Moreover, we found a correlation between methylation patterns of two genes in normal breast tissue. These data might assist to select subgroups of patients for the administration of alternative therapies.

Obtención de azúcares fermentables a partir de aserrín de pino pretratado secuencialmente con ácido base

The use of lignocellulosic waste constitutes an abundant and inexpensive source; it also offers a solution to the problem of waste disposal. The aim of the study was to evaluate the effect of different conditions of a sequential acid-base pretreatment of pine sawdust, through the release of reducing sugars in the saccharification step. The lignocellulosic material was pretreated in two stages: acid pretreatment (PT1), using sulfuric acid and basic pretreatment (PT2), employing sodium hydroxide at three levels each one: 1, 2 and 3 % in a factorial design. Enzymatic hydrolysis was carried out at 50 oC and 150 rpm in 50 mL vials. Samples were taken at 0.15, 24, 48, 72 and 96 h. The percentage of acid soluble lignin and the concentration of reducing sugars were determined. The optimum level of each factor favoring the highest delignification corresponded to 3 % sulfuric acid and 3 % sodium hydroxide. The production of reducing sugars was not affected by the PT2, but by the PT1, achieving a maximum for level 0 thereof (2 % of sulfuric acid). The sequential acid-base pretreatment was optimized and it was found that this pretreatment improves enzymatic hydrolysis of pine sawdust respect to unpretreated samples. The amount of reducing sugars obtained was comparable to that obtained by other authors.

Screening of new secretory cellulases from different supernatants of white rot fungi from Misiones, Argentina

ABSTRACT Cellulases hydrolyse the cellulose chain into single sugars efficiently. These sugars can be fermented in the bioethanol process, a source of renewable energy. Misiones rainforest is one of the most biodiverse systems on the planet subtropical ecoregions, which is the most probable site to find new fungal strains with potential for degrading cellulose through cellulases. The aim of this work was to find an efficient cellulolytic microorganism through the exploration of native white rot fungi from Misiones. From the qualitative screening 11 fungal strains were selected. The quantitative analysis revealed that the isolated LBM 033 was the best cellulases producer, reaching 57, 226 and 387 U/l of cellobiohydrolase, β-glucosidase and endoglucanase activity, respectively. The zymograms showed that the molecular mass of most of the endoglucanases ranged from 69 to 88 kDa and the molecular mass of most of the cellobiohydrolases was 45 kDa. The search of new cellulases of secretory organisms should lead to an efficient degradation of cellulosic materials, and thus facilitating potential applications in the production of bioenergy from lignocellulosic biomass.

Assessing the ability of white-rot fungi to tolerate polychlorinated biphenyls using predictive mycology

ABSTRACT The aim of the present study was to assess the ability of different white-rot fungi to tolerate polychlorinated biphenyls (PCBs) using predictive mycology, by relating fungal growth inhibition to ligninolityc enzyme secretion. Fungal strains were grown in the presence of PCBs in solid media and their radial growth values were modelled through the Dantigny-logistic like function in order to estimate the time required by the fungal colonies to attain half their maximum diameter. The principal component analysis (PCA) revealed an inverse correlation between strain tolerance to PCBs and the laccase secretion over time, being laccase production closely associated with fungal growth capacity. Finally, a PCA was run to regroup and split between resistant and sensitive fungi. Simultaneously, a function associated with a model predicting the tolerance to PCBs was developed. Some of the assayed isolates showed a promising capacity to be applied in PCB bioremediation. Abbreviations: Polychlorinated biphenyls (PCBs), white-rot fungi (WRF)