Unravelling the potential of susceptibility genes in plant disease management: Present status and future prospects

The increasing global population requires an equivalent increase in food production to meet the global food demand. Crop production is challenged by various biotic and abiotic stresses, which decrease crop yield and production. Thus, proper disease management for crops ensures global food security. Various chemical, physical, and biological disease control methods have been devised and used for plant protection. However, due to the low efficiency of these methods, modern research has shifted to genetic engineering approaches. The recent advances in molecular techniques have revealed the molecular mechanisms controlling the plant’s innate immune system and plant-pathogen interactions. Earlier studies revealed that the pathogens utilize the susceptibility (S) genes in hosts for their sustainability and disease development. The resistance achieved by suppressing the S genes expression provides resistance against pathogens. Exploiting S genes for imparting/enhancing disease resistance would offer a more durable and effective alternative to conventional disease control methods. Therefore, the present review highlights the potential of this novel tool for inducing disease resistance in plants

Changing Trends in Microalgal Energy Production- Review of Conventional and Emerging Approaches

The depletion of fossil fuel for energy production is one of the major problems being faced worldwide. As an alternative to fossil fuels, first and second generation biofuel was developed from corn, grains and lignocellulosic agricultural residues. These generations are inefficient in achieving the desired rate of biofuel production, climate change mitigation and economic growth. Therefore, third generation biofuel specifically derived from microalgae have proved to be a promising unconventional energy source. Microalgae are microscopic organisms that grow in salt or fresh water and have been used for producing metabolites, cosmetics and for energy production. The conventional approaches used for biofuel production include pyrolysis, gasification, direct combustion and thermomechanical liquefaction. The search for biological and eco-friendly approaches led to the emergence of Microbial Fuel Cell (MFC), which provide a new solution to energy crisis. Integration of photosynthetic organisms such as microalgae into MFC resulted in a new approach i.e. Microbial Solar Cell, which can convert solar energy into electrical energy via photosynthesis. Microbial solar cells have broad range application in wastewater treatment, biodiesel processing and intermediate metabolite production

Local ferroelectricity in thermoelectric SnTe above room temperature driven by competing phonon instabilities and soft resonant bonding

We report direct observation of local ferroelectric ordering above room temperature in rocksalt SnTe, which is a topological crystalline insulator and a good thermoelectric material. Although SnTe is known to stabilize in a ferroelectric ground state (rhombohedral phase) below ∼100 K, at high temperatures it was not expected to show any ferroelectric ordering forbidden by its globally centro-symmetric crystal structure (Fm-3m). Here, we show that SnTe exhibits local ferroelectric ordering that is robust above room temperature through direct imaging of ferroelectric domains by piezoresponse force microscopy and measurement of local polarization switching using switching spectroscopy. Using first-principles theoretical analysis, we show how the local ferroelectricity arises from soft bonding and competing phonon instabilities at intermediate wavelengths, which induce local Sn-off centering in the otherwise cetrosymmetric SnTe crystal structure. The results make SnTe an important member of the family of new multi-functional materials namely the ferroelectric-thermoelectrics

Nardostachys jatamansi (D.Don) DC.: An invaluable and constantly dwindling resource of the Himalayas

International audienceThe use of medicinal plant species for different therapeutic effects is well recognized around the globe. Nardostachys jatamansi (D.Don) DC. (Family: Caprifoliaceae Juss.), commonly known as Indian spikenard is a critically endangered medicinal plant which grows at high altitudes in the alpine and sub-alpine regions of the Himalayas. Its medicinal use is well-recognized in the Bhutanese, Chinese, Indian, Japanese, Nepalese and Tibetan medicine. Moreover, its medicinal properties are well established in traditional medicines including Ayurveda, Ben-Cao- Shi-Yi, Homer's Iliad, the Old Testament, as in conventional systems. The increasing national and international demand of N. jatamansi, mostly for the rhizomes (underground tissue), as well as illegal/unsustainable harvesting has brought this valuable species to the edge of extinction. Therefore, more research input including in vitro biotechnological approaches is required to ensure its sustainable utilization and long-term conservation. Further research is also needed to improve our current knowledge about its conservation status, clinical relevance, and bioactive components. This review comprehensively summarizes the currently available information on the ethnomedicinal uses, pharmacology, phytochemistry, trade value and potential role of modern plant biotechnology tools for the conservation of this high value plant. (c) 2020 SAAB. Published by Elsevier B.V. All rights reserved

Meta-topolin-mediated regeneration and accumulation of phenolic acids in the critically endangered medicinal plant Crinum malabaricum (Amaryllidaceae): A potent source of galanthamine

International audienceCrinum malabaricum (Family: Amaryllidaceae) is a critically endangered aquatic medicinal plant endemic to India. This species is a promising natural source of bioactive compounds including galanthamine (GAL), an anti-Alzheimer drug. In vitro regeneration in the Amaryllidaceae is often challenging. This study assessed the use of meta-Topolin (mT) on in vitro regeneration of C. malabaricum. Shoot explants were cultured on Murashige and Skoog (MS) medium supplemented with 0.5, 2.5, 5.0, 7.5 and 10.0 µM mT for six weeks, whereby 7.5 µM mT resulted in the maximum multiplication of adventitious shoots, much higher than the control. The biochemical accumulation of eleven different phenolic acids was quantified by UHPLC-MS/MS analysis, and it appeared that mT-treated cultures exhibited the highest concentration of phenolic acids. In particular, increased concentrations of gallic acid, protocatechuic acid, syringic acid, p-hydroxybenzoic acid, salicylic acid and vanillic acid were detected compared to the control. mT (2.5 and 5.0 µM) produced the maximum amount of chlorogenic acid, ferulic acid, p-coumaric acid and sinapic acid. However, an increased content of caffeic acid was produced on PGR-free medium. These findings highlight the beneficial effect and validate the rising importance of mT for in vitro regeneration studies. This study will serve as a potential protocol to conserve and restore the medically important C. malabaricum

Generation of Asynaptic Mutants in Potato by Disrupting <i>StDMC1</i> Gene Using RNA Interference Approach

Fixing the genomic composition and multiplication through true potato seed (TPS) is an important challenge in autotetraploid potato. Disrupted meiotic cDNA (DMC1) is a meiotic gene that plays a central role in DNA recombination through crossing over in meiosis. Using the Arabidopsis DMC1 (AtDMC1) gene sequence, we retrieved Solanum tuberosum DMC1(StDMC1) from the diploid potato genome, and subsequently, sense and antisense regions of the StDMC1 gene were amplified in potato cv. Kufri Jyoti. The sense and antisense fragments were confirmed by Sanger-sequencing and cloned in the pRI101 vector. Agrobacterium-mediated transformation of the RNAi construct resulted in 44% transformation efficiency, and a total of 137 mutant lines were obtained. These mutant lines were further validated through pollen viability testing, and selected lines were used for gene expression analysis. The acetocarmine-based pollen staining showed reduced pollen viability ranging from 14 to 21% in four DMC1 mutant lines (DMC4-37, DMC4-41, DMC6-20, and DMC6-21), as compared to the Kufri Jyoti control plants, which on average exhibited 78% pollen viability. The phenotypic data was supported by the reduced expression of the StDMC1 gene in these four mutant lines compared to the control Kufri Jyoti. The results confirmed the generation of StDMC1 knockdown lines. This is the first report of StDMC1 mutant line generation in tetraploid potatoes and will be a step forward in generating non-recombinant mutants through sexual reproduction in potatoes