Effect of nitrates on embryo induction efficiency in cotton (Gossypium hirsutum L.)

Cotton (Gossypium hirsutum L.) cv Coker-312 callus culture was assessed in terms of its usefulness as a system for investigating the effect of nitrates from different chemical compounds of nitrogen on embryo induction percentage in calli as the plant growth and cell differentiation mainly based on nitrogen. Both sources and amount of nitrogen in in vitro medium have significant effects mainly on cell growth, embryogenesis and the production of anthocyanin. Anthocyanin production is the best indication of inhibition of cell growth in in vitro culture of cotton. Embryo induction rate was high when NH4NO3 was eliminated from the medium but in the presence of KNO3. The dicotyledenary embryos were developed with in 5 weeks, these embryos developed into normal plantlets immediately when they were cultured on a simple MS basal medium supplemented with 3% glucose. Key words: Gossypium hirsutum L, callus induction, somatic embryogenesis, nitrogen sources, plant regeneration. African Journal of Biotechnology Vol.3(6) 2004: 319-32

Silencing of the AV2 gene by antisense RNA protects transgenic plants against a bipartite begomovirus

Whitefly-transmitted geminiviruses (genus Begomovirus) are phytopathogens that cause heavy losses to crops worldwide. Efforts to engineer resistance against these viruses are focused mainly on silencing of complementary-sense virus genes involved in virus replication. Here we have targeted a virion-sense gene (AV2) to develop resistance against Tomato leaf curl New Delhi virus, a bipartite begomovirus prevalent throughout the Indian subcontinent. We show that tobacco plants transformed with an antisense construct targeting this gene are resistant to the virus. Following challenged with the virus, transgenic plants remained symptomless, although viral DNA could be detected in some plants by PCR. This is the first report of transgenic resistance against a bipartite begomovirus obtained by targeting a virion-sense gene. The relatively conserved nature of the gene suggests that the technology may be useful to develop broad-spectrum resistance which is required because of the fact that plants are often infected with multiple begomoviruses in the field

Expression of a full length Arabidopsis vacuolar H+-pyrophosphatase (AVP1) gene in tobacco (Nicotiana tabbacum) to increase tolerance to drought and salt stresses

Among various abiotic stresses salinity and drought are the two major factors limiting the crop productivity. Genetically engineered salt and drought tolerant plants could provide an avenue to the reclamation of farmlands lost to agriculture because of salinity and a lack of rainfall. The Arabidopsis gene AVP1 encodes a vacuolar pyrophosphatase that functions as a proton pump and generates an electrochemical gradient in vacuole, thereby activating vacuolar membrane-antiporters including Na+/H+ antiporter, which helps in sequestration of Na+ into vacuole. In addition, over-expression of AVP1 gene increase vegetative growth by auxin transport and enhances auxin mediated root development, consequently achieving higher water absorption and retention capacities. The goal of present work is amplification of full length AVP1 (3.2kb) gene, from Arabidopsis thaliana genomic DNA through PCR, its cloning into a suitable plant expression vector and transformation in tobacco through Agrobacterium mediated transformation method for its characterization. PCR analysis showed the successful transformation of this gene in Nicotiana tabaccum. Screening of these putative transgenic plants against different salinity levels (50-250mM NaCl) showed that transgenic plants were tolerant to 250mM NaCl whereas the control plants showed wilting within 36-48 hours of salt treatment. Under periodic drought stress treatment transgenic (AVP1) plants were significantly more tolerant than wild type plants. Similarly the results of salinity and drought tolerance experiment in sand under saline and water regime conditions confirmed that introns play a key role in gene expression and regulations and improve the growth of plants. These resistant phenotypes are associated with increased internal stores of solutes

Pepper leaf curl Lahore virus requires the DNA B component of Tomato leaf curl New Delhi virus to cause leaf curl symptoms

<p>Abstract</p> <p>Background</p> <p>Begomoviruses are whitefly-transmitted geminiviruses with genomes that consist of either two components (known as DNA A and DNA B) or a single component (homologous to the DNA A component of bipartite begomoviruses). Monopartite begomoviruses are often associated with a symptom-modulating DNA satellite (collectively known as betasatellites). Both bipartite and monopartite begomoviruses with associated satellites have previously been identified in chillies showing leaf curl symptoms in Pakistan.</p> <p>Results</p> <p><b>A </b>chilli plant (<it>Capsicum annum</it>) with chilli leaf curl disease symptoms was found to contain a begomovirus, a betasatellite and the DNA B component of <it>Tomato leaf curl New Delhi virus </it>(ToLCNDV). The begomovirus consisted of 2747 nucleotides and had the highest sequence identity (99%) <it>with Pepper leaf curl Lahore virus </it>(PepLCLV-[PK: Lah:04], acc. no. AM404179). <it>Agrobacterium</it>-mediated inoculation of the clone to <it>Nicotiana benthamiana</it>, induced very mild symptoms and low levels of viral DNA, detected in systemically infected leaves by PCR. No symptoms were induced in <it>Nicotiana tabacum </it>or chillies either in the presence or absence of a betasatellite. However, inoculation of PepLCLV with the DNA B component of ToLCNDV induced leaf curl symptoms in <it>N. benthamiana</it>, <it>N. tabacum </it>and chillies and viral DNA accumulated to higher levels in comparison to plants infected with just PepLCLV.</p> <p>Conclusions</p> <p>Based on our previous efforts aimed at understanding of diversity of begomoviruses associated with chillies, we propose that PepLCLV was recently mobilized into chillies upon its interaction with DNA B of ToLCNDV. Interestingly, the putative rep-binding iterons found on PepLCLV (GGGGAC) differ at two base positions from those of ToLCNDV (GGTGTC). This is the first experimental demonstration of the infectivity for a bipartite begomovirus causing chilli leaf curl disease in chillies from Pakistan and suggests that component capture is contributing to the emerging complexity of begomovirus diseases in the region.</p

Bioinformatics: A Way Forward to Explore “Plant Omics”

Bioinformatics, a computer-assisted science aiming at managing a huge volume of genomic data, is an emerging discipline that combines the power of computers, mathematical algorithms, and statistical concepts to solve multiple genetic/biological puzzles. This science has progressed parallel to the evolution of genome-sequencing tools, for example, the next-generation sequencing technologies, that resulted in arranging and analyzing the genome-sequencing information of large genomes. Synergism of “plant omics” and bioinformatics set a firm foundation for deducing ancestral karyotype of multiple plant families, predicting genes, etc. Second, the huge genomic data can be assembled to acquire maximum information from a voluminous “omics” data. The science of bioinformatics is handicapped due to lack of appropriate computational procedures in assembling sequencing reads of the homologs occurring in complex genomes like cotton (2n = 4x = 52), wheat (2n = 6x = 42), etc., and shortage of multidisciplinary-oriented trained manpower. In addition, the rapid expansion of sequencing data restricts the potential of acquisitioning, storing, distributing, and analyzing the genomic information. In future, inventions of high-tech computational tools and skills together with improved biological expertise would provide better insight into the genomes, and this information would be helpful in sustaining crop productivities on this planet

The Effect Of Physical Fatigue On Football Referee's Decision Making

The role of the referee is very important, especially in professional football. Wrong decisions may have a profound impact on the outcome of the match. Research is needed to find out the aspects that influence referee decisions. This research aims to determine the effect of fatigue experienced by referees on decision making. This research used an experimental method with 16 football referees as the sample. The research instrument was a video test of soccer referee decision-making from UEFA 2022. The results of this research show a significant influence of fatigue experienced by referees on decision-making. Fatigue experienced by referees interferes with referees in making decision

Acid sphingomyelinase deactivation post-ischemia promotes brain angiogenesis and remodeling by small extracellular vesicles

Antidepressants have been reported to enhance stroke recovery independent of the presence of depressive symptoms. They have recently been proposed to exert their mood-stabilizing actions by inhibition of acid sphingomyelinase (ASM), which catalyzes the hydrolysis of sphingomyelin to ceramide. Their restorative action post-ischemia/reperfusion (I/R) still had to be defined. Mice subjected to middle cerebral artery occlusion or cerebral microvascular endothelial cells exposed to oxygen–glucose deprivation were treated with vehicle or with the chemically and pharmacologically distinct antidepressants amitriptyline, fluoxetine or desipramine. Brain ASM activity significantly increased post-I/R, in line with elevated ceramide levels in microvessels. ASM inhibition by amitriptyline reduced ceramide levels, and increased microvascular length and branching point density in wildtype, but not sphingomyelinase phosphodiesterase-1 ([Smpd1]−/−) (i.e., ASM-deficient) mice, as assessed by 3D light sheet microscopy. In cell culture, amitriptyline, fluoxetine, and desipramine increased endothelial tube formation, migration, VEGFR2 abundance and VEGF release. This effect was abolished by Smpd1 knockdown. Mechanistically, the promotion of angiogenesis by ASM inhibitors was mediated by small extracellular vesicles (sEVs) released from endothelial cells, which exhibited enhanced uptake in target cells. Proteomic analysis of sEVs revealed that ASM deactivation differentially regulated proteins implicated in protein export, focal adhesion, and extracellular matrix interaction. In vivo, the increased angiogenesis was accompanied by a profound brain remodeling response with increased blood–brain barrier integrity, reduced leukocyte infiltrates and increased neuronal survival. Antidepressive drugs potently boost angiogenesis in an ASM-dependent way. The release of sEVs by ASM inhibitors disclosed an elegant target, via which brain remodeling post-I/R can be amplified