Morphological and Molecular Analysis of Three Celery Accessions

Celery (Apium graveolens L.), a culinary herb and vegetable, is considered a good source of the essential oil and phenolic acids for use as a food, medicine, and flavoring agent. Substantial plant to plant variation within celery, however, indicates a high degree of genetic inconsistency that affects plant quality and yield. This study evaluated the fresh and dry weights and leaf characteristics of three celery genotypes grown in a greenhouse. The genotypes were also screened for polymorphic RAPD (Random Amplified Polymorphic DNA) markers. Celery Accessions were found to differ in fresh and dry weight. Our study demonstrated that RAPD technique could be a suitable tool for genotypes identification and classification in celery

Functional characterization of members of plasma membrane intrinsic proteins subfamily and their involvement in metalloids transport in plants

Aquaporins (AQPs) are channel proteins that facilitate the transport of water and various low molecular weight solutes including metalloids. Plant aquaporins have been divided into four major subfamilies: plasma membrane intrinsic proteins (PIPs), NOD26-like intrinsic proteins (NIPs), tonoplast intrinsic proteins (TIPs), and small basic intrinsic proteins (SIPs). Various studies have shown that the transport of metalloids including arsenite, antimonite, silicon and boron in plants is facilitated by members of NIP subfamily. In this study, we provided experimental evidences showing that members of rice PIP subfamily are involved in arsenite and boron permeability. RT-PCR analysis of seven OsPIPs; OsPIP1;2, OsPIP1;3, OsPIP2;4, OsPIP2;5, OsPIP2;6, OsPIP2;7, and OsPIP2;8 showed that these genes were downregulated under arsenite toxicity in shoots and roots. Whereas, these OsPIP genes were deferentially regulated in shoots and highly induced in roots by boron toxicity. Heterologous expression in Xenopus laevis oocytes showed that OsPIP2;4, OsPIP2;6, and OsPIP2;7 significantly increased the transport of arsenite. Expression of OsPIP candidate genes in HD9 yeast strain lacking the metalloids influx and efflux systems resulted in an increased boron sensitivity and accumulation. Overexpression of two OsPIP candidates; OsPIP1;3 and OsPIP2;6 in Arabidopsis yielded enhanced arsenite and boron tolerance with higher biomass and greater root length compared to wild type plants, however there was no difference in arsenic and boron accumulation in long-term uptake assays. Short duration exposure to AsIII resulted in both active influx and efflux of As in shoots and roots, suggesting a bidirectional transport activity of OsPIPs. Whereas, short-term uptake assay of tracer B (10B) in shoots and roots demonstrated increased 10 B influx in transgenic Arabidopsis lines indicating that these OsPIPs are also involved in mediating B transport in plants. We used RNAi approach to knockdown the expression of OsPIP1;3 and OsPIP2;6 in rice. We generated RNAi lines for both genes and qRT-PCR analysis showed a significant decrease in the transcript levels for OsPIP1;3 and OsPIP2;6. These RNAi lines will be the subject of future studies. These OsPIPs genes will be highly useful in developing arsenite and boron tolerant crops for enhanced yield in the areas affected by high As and B toxicity

Potential Biotechnological Strategies for the Cleanup of Heavy Metals and Metalloids

Global mechanization, urbanization and various natural processes have led to the increased release of toxic compounds into the biosphere. These hazardous toxic pollutants include a variety of organic and inorganic compounds, which pose a serious threat to the ecosystem. The contamination of soil and water are the major environmental concerns in the present scenario. This leads to a greater need for remediation of contaminated soils and water with suitable approaches and mechanisms. The conventional remediation of contaminated sites commonly involves the physical removal of contaminants, and their disposition. Physical remediation strategies are expensive, non-specific and often make the soil unsuitable for agriculture and other uses by disturbing the microenvironment. Owing to these concerns, there has been increased interest in eco-friendly and sustainable approaches such as bioremediation, phytoremediation and rhizomediation for the cleanup of contaminated sites. This review lays particular emphasis on biotechnological approaches and strategies for heavy metal and metalloid containment removal from the environment, highlighting the advances and implications of bioremediation and phytoremediation as well as their utilization in cleaning-up toxic pollutants from contaminated environments

Limited resources of genome sequencing in developing countries: Challenges and solutions

The differences between countries in national income, growth, human development and many other factors are used to classify countries into developed and developing countries. There are several classification systems that use different sets of measures and criteria. The most common classifications are the United Nations (UN) and the World Bank (WB) systems. The UN classification system uses the UN Human Development Index (HDI), an indicator that uses statistic of life expectancy, education, and income per capita for countries' classification. While the WB system uses gross national income (GNI) per capita that is calculated using the World Bank Atlas method. According to the UN and WB classification systems, there are 151 and 134 developing countries, respectively, with 89% overlap between the two systems. Developing countries have limited human development, and limited expenditure in education and research, among several other limitations. The biggest challenge facing genomic researchers and clinicians is limited resources. As a result, genomic tools, specifically genome sequencing technologies, which are rapidly becoming indispensable, are not widely available. In this report, we explore the current status of sequencing technologies in developing countries, describe the associated challenges and emphasize potential solutions

Factors controlling seed dormancy and germination response of Brachypodium hybridum growing in the hot arid mountains of the Arabian Desert

Seed dormancy and germination have been studied in the genetic model Brachypodium species complex in cooler, moist higher latitudes. Studying environmental factors in arid mountains affecting dormancy and germination in Brachypodium complex could determine the factors controlling these processes. This study assesses the impacts of temperature during seed maturation, seed after-ripening, drought, photoperiod, and thermoperiod on final germination and germination rate index of B. hybridum in the Arabian Desert. Seeds were germinated in dark and light and under different ratios of red:far red lights at three diurnal thermoperiods. The final germination percentage was significantly greater at 15/25 °C and 20/30 °C than at 25/35 °C and in light rather than in darkness. Seeds that reached maturity at 15/25 °C attained greater and faster germination than those that reached maturity at 20/30 °C. One-year after-ripening enhanced the final germination percentage and reduced photoperiod requirement. Light quality did not affect final germination percentage. Seeds tolerated drought of up to -0.8 MPa polyethylene glycol. The tolerance of B. hybridum seeds produced at higher thermoperiods to moderate levels of osmotic stress and their higher dormancy indicate that this species has the potential to survive the projected global warming in its native and introduced ranges.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Role of Endophytes and Rhizosphere Microbes in Promoting the Invasion of Exotic Plants in Arid and Semi-Arid Areas: A Review

Endophytes and rhizospheric microorganisms support invasive species’ adaptation to environmental stresses. Here, we review the impacts of endophytes, rhizospheric microbes (particularly symbiotic nitrogen-fixers), mycorrhiza and pathogens on plant invasion in arid and semi-arid areas. Endophytes and soil microorganisms either enhance nutrient acquisition for enhancing the invasive plant immune system and/or negatively affect native plants. In addition, the positive feedback between mycorrhizal fungi and invasive plants enhances the competitive ability of the aliens, providing them more opportunities for success, establishment, and dominance. The microbes and their secondary metabolites promote invasive plant species by changing soil microbial community structure and carbon biomass as well as enzyme activity, which improves soil properties and processes. The negative impact of invasive exotic plants on the associated biota and the role of allelochemicals are also discussed. It could be concluded that endophytes interact with rhizosphere microbes to promote invasive plant species in arid and semi-arid areas in a way similar to what happens in other ecosystems; the differences are in the pathways and reactions, which depend upon the prevailing abiotic factors. More interdisciplinary field experiments integrating microbial, biotechnological, and molecular approaches are needed to understand the role of symbiotic microbes in invasion biology

Quantitative resistance in potato leaves to late blight associated with induced hydroxycinnamic acid amides

Late blight is a serious economic threat to potato crop, sometimes leading to complete crop loss. The resistance in potato to late blight can be qualitative or quantitative in nature. Qualitative resistance is not durable. Though quantitative resistance is durable, the breeding is challenging due to polygenic inheritance. Several quantitative trait loci (QTLs) have been identified, but the mechanisms of resistance are largely unknown. A nontargeted metabolomics approach was used to identify resistance-related (RR) metabolites in a resistant genotype (F06025), as compared to a susceptible (Shepody) genotype, mock- or pathogen-inoculated. The RR metabolites, which had high fold change in abundance, mainly belonged to phenylpropanoid, flavonoid, fatty acid, and alkaloid chemical groups. The most important phenylpropanoids identified were hydroxycinnamic acid amides, the polyaromatic domain of suberin that is known to be associated with cell wall reinforcement. These metabolites were mapped on to the potato metabolic pathways, and the candidate enzymes and their coding genes were identified. A quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay revealed a higher upregulation of 4-coumarate: CoA ligase (4-CL), tyrosine decarboxylase (TyDC), and tyramine hydroxycinnamoyl transferase (THT) in the pathogen-inoculated resistant genotype than in susceptible. These genes were sequenced in both resistant and susceptible genotypes, and nonsynonymous single-nucleotide polymorphisms (nsSNPs) were found. The application of these genes in potato resistance improvement, following validation, is discussed