Liming enhances longevity of wheat seeds produced in acid soils.

The environment where plants grow, such as acidic soils, interferes with the nutrient concentration and physiological quality of seeds. This hypothesis was tested using wheat seeds as a model crop, grown in a tropical soil with and without lime application for twelve years. Here we show that lime provides remarkable enhancements in soil chemistry and seed composition, without altering the seed's germination and vigor. Also, it favors the production of seeds with additional molecular mechanisms that extend their longevity. Our results indicate that the application of lime mitigates acidity in tropical soils and ensures the production of seeds with enhanced chemical composition and longer life span.

What happens when the rain is back? A hypothetical model on how germination and post-germination occur in a species from transient seed banks.

We hypothesize that by simulating the natural priming in seeds of a species that forms transient seed banks it is possible to clarify molecular aspects of germination that lead to the recruitment of seedlings when the next rainy season begins. We used seeds of Solanum lycocarpum as a biological model. Our findings support the idea that the increment of seed germination kinetics when the rainy season returns is mainly based on the metabolism and embryonic growth, and that the hydropriming, at the end of seed dispersion, increases the germination window time of these seeds by mainly increasing the degradation of galactomannan of the cell wall. This can improve the energy supply (based on carbon metabolism) for seedling growth in post-germination, which improves the seedling's survival chances. From these findings, we promote a hypothetical model about how the priming at the end of the rainy season acts on mRNA synthesis in the germination of seeds from transient banks and the consequence of this priming at the beginning of the following rainy season. This model predicts that besides the Gibberellin and Abscisic Acid balance (content and sensitivity), Auxin would be a key component for the seed-seedling transition in Neotropical areas. Seed collection was performed under authorization number SISGEN AB0EB45.

The receptor-like kinase SlSOBIR1 is differentially modulated by virus infection but its overexpression in tobacco has no significant impact on virus accumulation.

KEY MESSAGE: The role of the tomato receptor-like kinase SlSOBIR1 in antiviral defense was investigated. SlSOBIR1 was transcriptionally modulated by unrelated viruses but its ectopic expression had no effect on virus accumulation. Leucine-rich repeat receptor-like kinases (LRR-RLK) constitute a diverse group of proteins allowing the cell to recognize and respond to the extracellular environment. In the present study we focused on a gene encoding a tomato LRR-RLK (named SlSOBIR1) involved in the host defense against fungal pathogens. Curiously, SlSOBIR1 has been previously reported to be down-regulated by Pepper yellow mosaic virus (PepYMV) infection. Here, we show that SlSOBIR1 is responsive to wounding and differentially modulated by unrelated virus infection, i.e., down-regulated by PepYMV and up-regulated by Tomato chlorotic spot virus (TCSV). Despite these divergent expression profiles, SlSOBIR1 overexpression in transgenic tobacco plants had no evident effect on TCSV and PepYMV accumulation. On the other hand, overexpression of SlSOBIR1 significantly increased the expression of selected defense genes (PR-1a and PR-6) and exacerbated superoxide production in wounded leaves. Our data indicate that the observed modulation of SlSOBIR1 expression is probably triggered by secondary effects of the virus infection process and suggest that SlSOBIR1 is not directly involved in antiviral signaling response.

A influência de cultivares de amoreiras adubadas sobre características biológicas e produtivas do bicho-da-seda (Bombyx mori L) / The influence of mulberry cultivation with fertilizers on biological characteristics and production performance in silkworm (Bombyx mori L) / La influencia de los cultivares de moreras con abono bajo características biológicas y productivas del gusano de seda (Bombyx mori L)

A cultura da amoreira (Morus alba L.) é essencial para a manutenção dos barracões de criação do bicho-da-seda (Bombyx mori L.). A qualidade nutricional das folhas relaciona-se diretamente com a produção dos casulos, e consequentemente na renda final do produtor. Este artigo tem como objetivo avaliar a influência da adubação química e orgânica, sobre o desenvolvimento das plantas de amora de três diferentes genótipos quanto a caracteres biológicos e produtivos de bicho-da-seda. Para isso, foi aplicado adubo químico NPK, esterco de galinha e uma testemunha para cada um dos genótipos avaliados. Foram coletadas informações referentes à biomassa fresca, biomassa seca das amoreiras, peso e comprimento da lagarta, peso da glândula sericígena, peso e teor de seda dos casulos. A cultivar FM 86 apresentou maior desempenho produtivo, independentemente do tipo de adubação. Os caracteres biológicos e produtivos foram influenciados pelos tratamentos, no entanto, a variável que apresenta maior importância econômica, o teor líquido de seda nos casulos obteve médias estatisticamente semelhantes entre os genótipos de amoreiras submetidas aos diferentes tratamentos.

The mulberry culture (Morus alba L.) is essential to silkworm rearing (Bombyx mori L.). The nutritional quality of the leaves relates directly in the cocoons production and, consequently in the final income of the producer. This work aims to evaluate the influence of the chemical and organic manure on the development from three mulberry genotypes and, consequently, the importance of each genotype on the biological and productive characters of the commercial hybrid silkworm. For this, it was used chemical fertilizer NPK, chicken manure and a witness for each one of the evaluated genotypes. The collected data were: fresh biomass and dry biomass of the mulberry, the silkworm mature larval weight and corporal size, silk gland and cocoon weight and raw silk percentage. The genotype FM 86 was the most productive with both, chemical and organic fertilizer. The silkworm biological and productive characters were influenced by the treatments; however, the most important economically variable, the raw silk percentage, did not show averages statically significant among the different cultivars and or the treatments.

El cultivo de morera (Morus alba L.) es esencial para el mantenimiento de los barracones de creación del gusano de seda (Bombyx mori L.). La calidad nutricional de las hojas se relaciona directamente con la producción de los capullos, y consecuentemente en la renta final del productor. Esta investigación tiene por objeto evaluar la influencia de la fertilización orgánica y química, sobre el desarrollo de las plantas de morera de tres genotipos diferentes cuanto a rasgos biológicos y productivos del gusano de seda. Para eso, se aplicó el fertilizante NPK, estiércol de pollo y un control para cada uno de los genotipos evaluados. Hemos recopilado informaciones sobre la biomasa fresca, biomasa seca de las moreras, peso y longitud de la oruga, peso de la glándula sericígena, peso y contenido de los capullos de seda. La cultivar FM 86 presentó mayor desempeño productivo, independientemente del tipo de fertilización. Rasgos biológicos y productivos se han influenciados por los tratamientos, sin embargo, la variable que presenta mayor importancia económica es el contenido líquido de seda en los capullos, que obtuvo porcentaje estadísticamente similar entre los genotipos de moreras sometidas a diferentes tratamientos.

Sequence and analysis of the mitochondrial DNA control region in the sugarcane borer Diatraea saccharalis (Lepidoptera: Crambidae)

This study aimed at the sequence and analysis of the mtDNA control region (CR) of the Diatraea saccharalis. The genome PCR amplification was performed using the complementary primers to the flanking regions of Bombyx mori CR mitochondrial segment. The sequencing revealed that the amplified product was 568 bp long, which was smaller than that observed for B. mori (725 bp). Within the amplified segment, a sequence with 338 nucleotides was identified as the control region, which displayed a high AT content (93.5%). The D. saccharalis mtDNA CR multiple sequence alignment analysis showed that this region had high similarity with the Lepidoptera Cydia pomonella.

A broca da cana, Diatraea saccharalis pertence à família dos lepidópteros. A presença da larva pode ser extremamente destrutiva, chegando a inviabilizar a atividade canavieira, causando prejuízos consideráveis à agroindústria sucro-alcooleira. Atualmente a broca da cana vem sendo extinta da plantação por métodos de controle biológico, entretanto a evolução desses programas depende de maiores conhecimentos básicos da biologia molecular deste inseto. O estudo do segmento do genoma mitocondrial denominado região controle é amplamente utilizado em análises genéticas e filogenéticas em insetos. O objetivo desse trabalho foi sequenciar e analisar a região controle do genoma mitocondrial de Diatraea saccharalis. Esse segmento apresentou 338 nucleotídeos, menor que o observado em Bombyx mori, com conteúdo de 93,5% de A/T. As analises realizadas mostraram que Diatraea saccharalis apresenta 76% de similaridade com Cydia pomonella.

Cytopathological process by multiple nucleopolyhedrovirus in the testis of Bombyx mori L., 1758 (Lepidoptera: Bombycidae).

A cytopathological methodology was used to analyze infection by Bombyx mori multiple nucleopolyhedrovirus (BmMNPV), a geographic isolate of the family Baculoviridae, in the caterpillar testes of the B. mori. Japanese B. mori strain caterpillar, fifth instar, were inoculated with BmMNPV and their testes were collected and processed for light and transmission electronic microscopy. Epithelial coating cells and interfollicular septa in testes were susceptible to BmMNPV. The first evidence of infection was detected on the 6th day post-inoculation (p.i.) in the external epithelium, and on the 7th day p.i. in the internal epithelium and interfollicular septa. Cytopathological characteristics consisted of hypertrophied nuclei, the formation of virogenic stroma, and the occlusion of virions in polyhedron protein crystals in several stages of development. At the end of the infectious process, cell lysis and release of polyhedra into the extracellular medium occurred. Histopathology revealed early infection foci in the surrounding regions of tracheal insertions, thus underlining the role of the trachea as an infection-spreading organ in insects. This spreading occurs through penetration of the basal lamina, which facilitates entry of the budded virus into the testis. Additionally, an alignment of a partial sequence of the ORF 14 of the BmMNPV geographic isolate with other NPV certified the virus genera.

Intrinsic bent DNA colocalizes with the sequence involved in the Nd-sD mutation in the Bombyx mori fibroin light chain gene.

Multiple sequence alignments of the Bombyx mori fibroin light chain gene (fib-L) from hybrids and from Chinese and Japanese strains demonstrated that 51.6% of the fib-L third intron is conserved. One of these conserved segments, 41 bp long, contains the sequence CGTTATTATACATATT, which is duplicated in the B. mori Nd-s(D) mutant. In the present work, electrophoretic mobility assays and computational analyses revealed a major peak of intrinsic bent DNA within the segment that undergoes breakage in the previously-described Nd-s(D) mutation. This result suggested that this intrinsically-curved region might mediate DNA cleavage and enhance recombination events in the third intron of the Bombyx mori fib-L gene.

Amplificação por PCR da região controle do DNA mitocondrial de raças de bombyx mori / Bombyx mori mitocondrial DNA control region amplification by PCR / Amplificación por pcr de la región control del dna mitocondrial de razas de Bombyx mori

A sericicultura é uma importante atividade agroindustrial no Brasil, sendo o Estado do Paraná responsável por aproximadamente 90% de toda a produção nacional. A localização de marcadores genéticos para o bicho-da-seda (Bombyx mori L.) é importante para a diferenciação intra e interespecífica e para o uso em melhoramento genético da espécie, sendo o DNA mitocondrial (DNAmt) um dos marcadores genéticos mais utilizados no estudo de insetos. O objetivo deste trabalho foi amplificar a região controle do DNA mitocondrial de quatro raças de Bombyx mori, pela técnica de Polymerase Chain Reaction (PCR). Obteve-se a amplificação de um fragmento de aproximadamente 750 pb referente à região controle, demonstrando a eficiência da metodologia empregada para a amplificação desta região específica do DNAmt de Bombyx mori.

Sericulture is an important agro industrial activity in Brazil, mainly in Paraná State, that is responsible for 90% of the national production. For the genetic improvement of silkworm (Bombyx mori L.), it is necessary to develop techniques to amplify molecular markers in order to use it on genetic analysis. Mitochondrial DNA (mtDNA) has been widely used as a molecular marker for insects and provides suitable markers for studies on genetic variability and molecular characterization. The control region is the major non-coding region of animal mtDNA and has been responsible for providing important evolutionary data about many insect groups. The aim of this paper was to amplify the mtDNA control region of four Bombyx mori strains by polymerase chain reaction (PCR). A 750 bp fragment including the control region was amplified showing the efficiency of the methodology to amplify specific regions of the Bombyx mori mtDNA.

La sericicultura es una importante actividad agroindustrial en Brasil, siendo el Estado del Paraná responsable por aproximadamente 90% de toda la producción nacional. La localización de marcadores genéticos para el gusano de seda (Bombyx mori L.) es importante para la diferenciación intra e interespecífica y para el uso en mejoramiento genético de la especie, siendo el DNA mitocondrial (DNAmt) uno de los marcadores genéticos más utilizados en el estudio de insectos. El objetivo de esta investigación fue amplificar la región control del DNA mitocondrial de cuatro razas de Bombyx mori, por la técnica de Polymerase Chain Reaction (PCR). Se obtuvo la amplificación de un fragmento de aproximadamente 750 pb referente a la región control, demostrando la eficiencia de la metodología empleada para la amplificación de esta región específica del DNAmt de Bombyx mori.

Transferability and use of microsatellite markers for the genetic analysis of the germplasm of some Arachis section species of the genus Arachis

The Arachis section is the most important of the nine sections of the genus Arachis because it includes the cultivated peanut, Arachis hypogaea. The genetic improvement of A. hypogaea using wild relatives is at an early stage of development in spite of their potential as sources of genes, including those for disease and pests resistance, that are not found in the A. hypogaea primary gene pool. Section Arachis species germplasm has been collected and maintained in gene banks and its use and effective conservation depends on our knowledge of the genetic variability contained in this material. Microsatellites are routinely used for the analysis of genetic variability because they are highly polymorphic and codominant. The objective of this study was to evaluate the transferability of microsatellite primers and the assay of genetic variability between and within the germplasm of some species of the Arachis section. Fourteen microsatellite loci developed for three different species of Arachis were analyzed and 11 (78 percent) were found to be polymorphic. All loci had transferability to all the species analyzed. The polymorphic loci were very informative, with expected heterozygosity per locus ranging from 0.70 to 0.94. In general, the germplasm analyzed showed wide genetic variation.

Heterologous microsatellite primer pairs informative for the whole genus Arachis

The genus Arachis currently comprises 69 described species, some of which have potential and real value as human and animal foods. These Arachis species have been collected and maintained in germplasm banks to provide material that can be used as sources of genes in breeding programs and for the selection of new cultivars. One of the principal objectives of germplasm conservation is the evaluation of genetic variability, which is best conducted using molecular markers. We investigated the use of heterologous primers to amplify microsatellite loci that could be used to evaluate genetic variability in Arachis germplasm. Fifteen microsatellite primer pairs were tested in 76 accessions of 34 species from the nine Arachis sections. The data indicated that heterologous primers were very useful in Arachis since they had high transferability among the species (91 percent) and allowed the amplification of very polymorphic putative loci, which allowed both the characterization of most accessions and to make inferences about the mating systems of some species analyzed. Our data also revealed that the germplasm analyzed showed high variability, even when represented by few accessions.