Reactive oxygen species

Plants often face the challenge of severe environmental conditions,which include various biotic and abiotic stresses that exert adverse effects on plant growth and development. During evolution,plants have evolved complex regulatory mechanisms to adapt to various environmental stressors. One of the consequences of stress is an increase in the cellular concentration of reactive oxygen species(ROS),which are subsequently converted to hydrogen peroxide(H2O2). Even under normal conditions,higher plants produce ROS during metabolic processes. Excess concentrations of ROS result in oxidative damage to or the apoptotic death of cells. Development of an antioxidant defense system in plants protects them against oxidative stress damage. These ROS and,more particularly,H2O2,play versatile roles in normal plant physiological processes and in resistance to stresses. Recently,H2O2 has been regarded as a signaling molecule and regulator of the expression of some genes in cells. This review describes various aspects of H2O2 function,generation and scavenging,gene regulation and cross-links with other physiological molecules during plant growth,development and resistance responses.

Hydrogen Peroxide in Plants:a Versatile Molecule of the Reactive Oxygen Species Network

Bananas and plantains (Musa spp.) are among the most important crops in the world due to their nutritional and export value. However, banana production has been devastated by fungal infestations caused by Fusarium oxysporum f. sp. cubense (Foc), which cannot be effectively prevented or controlled. Since there is very little known about the molecular mechanism of Foc infections; therefore, we aimed to investigate the transcriptional changes induced by Foc in banana roots. We generated a cDNA library from total RNA isolated from banana roots infected with Foc Tropical Race 4 (Foc TR 4) at days 0, 2, 4, and 6. We generated over 26 million high-quality reads from the cDNA library using deep sequencing and assembled 25,158 distinct gene sequences by de novo assembly and gap-filling. The average distinct gene sequence length was 1,439 base pairs. A total of 21,622 (85.94%) unique sequences were annotated and 11,611 were assigned to specific metabolic pathways using the Kyoto Encyclopedia of Genes and Genomes database. We used digital gene expression (DGE) profiling to investigate the transcriptional changes in the banana root upon Foc TR4 infection. The expression of genes in the Phenylalanine metabolism, phenylpropanoid biosynthesis and alpha-linolenic acid metabolism pathways was affected by Foc TR4 infection. The combination of RNA-Seq and DGE analysis provides a powerful method for analyzing the banana root transcriptome and investigating the transcriptional changes during the response of banana genes to Foc TR4 infection. The assembled banana transcriptome provides an important resource for future investigations about the banana crop as well as the diseases that plague this valuable staple food.

https://link.springer.com/content/pdf/10.1186%2F1471-2164-13-650.pdf

De Novo characterization of the banana root transcriptome and analysis of gene expression under Fusarium oxysporum f. sp. Cubense tropical race 4 infection

Although banana (Musa sp.) is an important edible crop, contributing towards poverty alleviation and food security, limited transcriptome datasets are available for use in accelerated molecular-based breeding in this genus. 454 GS-FLX Titanium technology was employed to determine the sequence of gene transcripts in genotypes of Musa acuminata ssp. burmannicoides Calcutta 4 and M. acuminata subgroup Cavendish cv. Grande Naine, contrasting in resistance to the fungal pathogen Mycosphaerella musicola, causal organism of Sigatoka leaf spot disease. To enrich for transcripts under biotic stress responses, full length-enriched cDNA libraries were prepared from whole plant leaf materials, both uninfected and artificially challenged with pathogen conidiospores. The study generated 846,762 high quality sequence reads, with an average length of 334 bp and totalling 283 Mbp. De novo assembly generated 36,384 and 35,269 unigene sequences for M. acuminata Calcutta 4 and Cavendish Grande Naine, respectively. A total of 64.4% of the unigenes were annotated through Basic Local Alignment Search Tool (BLAST) similarity analyses against public databases. Assembled sequences were functionally mapped to Gene Ontology (GO) terms, with unigene functions covering a diverse range of molecular functions, biological processes and cellular components. Genes from a number of defense-related pathways were observed in transcripts from each cDNA library. Over 99% of contig unigenes mapped to exon regions in the reference M. acuminata DH Pahang whole genome sequence. A total of 4068 genic-SSR loci were identified in Calcutta 4 and 4095 in Cavendish Grande Naine. A subset of 95 potential defense-related gene-derived simple sequence repeat (SSR) loci were validated for specific amplification and polymorphism across M. acuminata accessions. Fourteen loci were polymorphic, with alleles per polymorphic locus ranging from 3 to 8 and polymorphism information content ranging from 0.34 to 0.82. A large set of unigenes were characterized in this study for both M. acuminata Calcutta 4 and Cavendish Grande Naine, increasing the number of public domain Musa ESTs. This transcriptome is an invaluable resource for furthering our understanding of biological processes elicited during biotic stresses in Musa. Gene-based markers will facilitate molecular breeding strategies, forming the basis of genetic linkage mapping and analysis of quantitative trait loci.

/pdf/analysis-of-the-leaf-transcriptome-of-musa-acuminata-during-47ky5br60u.pdf

Analysis of the leaf transcriptome of Musa acuminata during interaction with Mycosphaerella musicola: gene assembly, annotation and marker development

Smut caused by Sporisorium scitamineum is one of the important diseases of sugarcane with global significance. Despite the intriguing nature of sugarcane, S. scitamineum interaction, several pertinent aspects remain unexplored. This study investigates the proteome level alterations occurring in the meristem of a S. scitamineum infected susceptible sugarcane cultivar at whip emergence stage. Differentially abundant proteins were identified by 2DE coupled with MALDI-TOF/TOF-MS. Comprehensively, 53 sugarcane proteins identified were related to defence, stress, metabolism, protein folding, energy, and cell division; in addition, a putative effector of S. scitamineum, chorismate mutase, was identified. Transcript expression vis-a-vis the activity of phenylalanine ammonia lyase was relatively higher in the infected meristem. Abundance of seven candidate proteins in 2D gel profiles was in correlation with its corresponding transcript expression levels as validated by qRT-PCR. Furthermore, this study has opened up new perspectives on the interaction between sugarcane and S. scitamineum.

Proteomic analysis of a compatible interaction between sugarcane and Sporisorium scitamineum

Mycosphaerella fijiensis, a hemibiotrophic fungus, is the causal agent of black leaf streak disease, the most serious foliar disease of bananas and plantains. To analyze the compatible interaction of M. fijiensis with Musa spp., a suppression subtractive hybridization (SSH) cDNA library was constructed to identify transcripts induced at late stages of infection in the host and the pathogen. In addition, a full-length cDNA library was created from the same mRNA starting material as the SSH library. The SSH procedure was effective in identifying specific genes predicted to be involved in plant–fungal interactions and new information was obtained mainly about genes and pathways activated in the plant. Several plant genes predicted to be involved in the synthesis of phenylpropanoids and detoxification compounds were identified, as well as pathogenesis-related proteins that could be involved in the plant response against M. fijiensis infection. At late stages of infection, jasmonic acid and ethylene signaling transduction pathways appear to be active, which corresponds with the necrotrophic life style of M. fijiensis. Quantitative PCR experiments revealed that antifungal genes encoding PR proteins and GDSL-like lipase are only transiently induced 30 days post inoculation (dpi), indicating that the fungus is probably actively repressing plant defense. The only fungal gene found was induced 37 dpi and encodes UDP-glucose pyrophosphorylase, an enzyme involved in the biosynthesis of trehalose. Trehalose biosynthesis was probably induced in response to prior activation of plant antifungal genes and may act as an osmoprotectant against membrane damage.

Analysis of expressed sequence tags derived from a compatible Mycosphaerella fijiensis–banana interaction

Black leaf streak disease (BLSD) caused by Mycosphaerella fijiensis is considered the most destructive and costly foliar disease that affects bananas and plantains. In spite of some recent progress regarding the study of M. fijiensis-Musa spp. interaction, there is still limited information for this pathosystem. To gain insights into the molecular mechanisms behind the M. fijiensis-Musa spp. interaction, gene expression and biochemical analysis related with primary metabolism, methyl cycle, antioxidant and phenylpropanoid pathways were conducted. Early screening of the resistant cultivar (cv.) ‘Calcutta 4’ (Musa AA) and the susceptible cv. ‘Grande naine’ (Musa AAA) plants infected with M. fijiensis was effective at looking for defense-related genes. Quantitative PCR experiments showed up-regulation of Photosystem I reaction center subunit N chloroplastic-like (primary metabolism) and S-adenosyl-
 L-methionine synthetaste (methyl cycle) genes in the incompatible interaction, as well as down-regulation of the phenylpropanoid pathway genes in the susceptible cv. ‘Grande naine’ as main finding of this study. Improved knowledge concerning the M. fijiensis-Musa spp. interaction could help to establish innovative approaches for plant breeding programs against BLSD.

Early regulation of primary metabolism, antioxidant, methyl cycle and phenylpropanoid pathways during the Mycosphaerella fijiensis-Musa spp. interaction

2se infiltraron al vacio, se centrifugaron y al recobrado obtenido se le anadio sulfato de amonio al 80% (p/v) para la precipitacion de las proteinas, las que posteriormente se analizaron en un gel de poliacrilamida desnaturalizante al 12%. Se obtuvo una concentracion de proteinas promedio de 0.43 mg.ml-1 para muestras sanas y de 0.83 hasta 1.0 mg.ml -1 en las infectadas. Los resultados constituyen el paso inicial en el estudio del patosistema MusaMycosphaerella fijiensis, lo que permitira conocer acerca de las proteinas involucradas en la interaccion, como aspecto esencial a tener en cuenta para el desarrollo de las futuras estrategias de resistencia a patogenos. Palabras clave: electroforesis desnaturalizante, precipitacion salina, purificacion de proteinas

/pdf/extraccion-de-proteinas-a-partir-del-fluido-intercelular-en-587gwu6jot.pdf

Extracción de proteínas a partir del fluido intercelular en hojas de banano, cultivar 'Grande naine' (Musa AAA)

In Musa spp. considerable economical lost are cause by Mycosphaerella fijiensis infection around the world, that is why the study of the pathosystem constitute a priority. However, the main mechanisms activated in banana after infection are still unknown and are a limitation for a better understanding of this complex relationship. The objective of this study was to determine the effect of hydrogen peroxide (H2O2) application, on leaves of ‘Grande naine’ plants, on black leaf streak disease development (BLSD). For this purpose, the first three open leaves of banana plants were inoculated with the monoascosporic isolate of M. fijiensis CCIBPPf-83. At three days post-inoculation different H2O2 concentrations (10, 20, 30 and 40 mmol l -1) were sprayed to these plants as well as to non-inoculated ones. During the time course of the experiment for inoculated, sprayed plants and for control plants (infected with M. fijiensis) epidemiological variables as well as the area of necrotic lesions at 49 dpi were measured. The findings of this analysis showed that the early application of H2O2 have influence on the BLSD development.

Effect of H2O2 application during 'Grande naine'-Mycosphaerella fijiensis interaction.

In Musa spp. considerable economical lost are cause by Mycosphaerella fijiensis infection around the world, that is why the study of the pathosystem constitute a priority. However, the main mechanisms activated in banana after infection are still unknown and are a limitation for a better understanding of this complex relationship. The objective of this study was to determine the effect of hydrogen peroxide (H 2 O 2 ) application, on leaves of ‘Grande naine’ plants, on black leaf streak disease development (BLSD). For this purpose, the first three open leaves of banana plants were inoculated with the monoascosporic isolate of M . fijiensis CCIBP- Pf -83. At three days post-inoculation different H 2 O 2 concentrations (10, 20, 30 and 40 mmol l -1 ) were sprayed to these plants as well as to non-inoculated ones. During the time course of the experiment for inoculated, sprayed plants and for control plants (infected with M. fijiensis ) epidemiological variables as well as the area of necrotic lesions at 49 dpi were measured. The findings of this analysis showed that the early application of H 2 O 2 have influence on the BLSD development. Keywords: banana, black leaf streak disease, hemibiotrophic, hydrogen peroxide

/pdf/efecto-de-la-aplicacion-del-h-2-o-2-durante-la-interaccion-59pjoaorb7.pdf

Milady Mendoza-Rodríguez

Papers

Analysis of expressed sequence tags derived from a compatible Mycosphaerella fijiensis–banana interaction

Early regulation of primary metabolism, antioxidant, methyl cycle and phenylpropanoid pathways during the Mycosphaerella fijiensis-Musa spp. interaction

Extracción de proteínas a partir del fluido intercelular en hojas de banano, cultivar 'Grande naine' (Musa AAA)

Effect of H2O2 application during 'Grande naine'-Mycosphaerella fijiensis interaction.

Efecto de la aplicación del H 2 O 2 durante la interacción ‘Grande naine’- Mycosphaerella fijiensis