Abiotic Stresses in Agroecology: A Challenge for Whole Plant Physiology

• Record Nr.: UNINA9910227346403321
• Autore: Alison H. Kingston-Smith
• Pubbl/distr/stampa: Frontiers Media SA, 2017
• Descrizione fisica: 1 online resource (177 p.)
• Collana: Frontiers Research Topics
• Soggetti: Environmental economics
• Lingua di pubblicazione: Inglese
• Formato: Materiale a stampa
• Livello bibliografico: Monografia
• Sommario/riassunto: Understanding plant responses to abiotic stresses is central to our ability to predict the impact of global change and environmental pollution on the production of food, feed and forestry. Besides increasing carbon dioxide concentration and rising global temperature, increasingly frequent and severe climatic events (e.g. extended droughts, heat waves, flooding) are expected in the coming decades. Additionally, pollution (e.g. heavy metals, gaseous pollutants such as ozone or sulfur dioxide) is an important factor in many regions, decreasing plant productivity and product quality. This Research topic focuses on stress responses at the level of whole plants, addressing biomass-related processes (development of the root system, root respiration/fermentation, leaf expansion, stomatal regulation, photosynthetic capacity, leaf senescence, yield) and interactions between organs (transport via xylem and phloem, long-distance signaling and secondary metabolites). Comparisons between species and between varieties of the same species are helpful to evaluate the potential for species selection and genetic improvement. This research topic is focused on the following abiotic stresses and interactions between them: - Increased carbon dioxide concentration in ambient air is an important parameter influenced by global change and affects photosynthesis, stomatal regulation, plant growth and finally yield. - Elevated temperature: both the steady rise in average temperature and extreme events of shorter duration (heat waves) must be considered in ; the context of alterations in carbon balance through increased photorespiration, decreased Rubisco activation and carboxylation efficiency, damage to photosynthetic apparatus, as well as loss of water via transpiration and stomatal sensitivity. - Low temperatures (late frosts, prolonged cold phases, freezing temperature) can decrease overwintering survival rates, productivity of crop plants and species composition in meadows. - Water availability: More frequent, severe and extended drought periods have been predicted by climate change models. The timing and duration of a drought period is crucial to determining plant responses, particularly if the drought event coincides with an increase in temperature. Drought causes stomatal closure, decreasing the cooling potential of transpiration and potentially leading to thermal stress as leaf temperature rises. Waterlogging may become also more relevant during the next decades and is especially important for seedlings and young plants. It is not the presence of water itself that causes the stress, but the exclusion of oxygen from the soil which causes a decrease in respiration and an increase in fermentation rates followed by a period of potential oxidative stress as water recedes. - Salinity: high salt concentration in soil influences soil water potential, the water status of the plant and hence affects productivity. Salt tolerance will become an important trait driven by increased competition for land and the need to exploit marginal lands.

How Can Secretomics Help Unravel the Secrets of Plant-Microbe Interactions?

• Record Nr.: UNINA9910220044903321
• Autore: Delphine Vincent
• Pubbl/distr/stampa: Frontiers Media SA, 2017
• Descrizione fisica: 1 online resource (188 p.)
• Collana: Frontiers Research Topics
• Soggetti: Botany & plant sciences
• Lingua di pubblicazione: Inglese
• Formato: Materiale a stampa
• Livello bibliografico: Monografia
• Sommario/riassunto: Secretomics describes the global study of proteins that are secreted by a cell, a tissue or an organism, and has recently emerged as a field for which interest is rapidly growing. The term secretome was first coined at the turn of the millennium and was defined to comprise not only the native secreted proteins released into the extracellular space but also the components of machineries for protein secretion. Two secretory pathways have been described in fungi: i) the canonical pathway through which proteins bearing a N-terminal peptide signal can traverse the endoplasmic reticulum and Golgi apparatus, and ii) the unconventional pathway for proteins lacking a peptide signal. Protein secretion systems are more diverse in bacteria, in which types I to VII pathways as well as Sec or two-arginine (Tat) pathways have been described. In oomycete species, effectors are mostly small proteins containing an N-terminal signal peptide for secretion and additional C-terminal motifs such as RXLRs and CRNs for host targeting. It has recently been shown that oomycetes exploit non-conventional secretion mechanisms to transfer certain proteins to the extracellular environment. Other non-classical secretion systems involved in plant-fugal interaction include extracellular vesicles (EVs, Figure 1 from Samuel et al 2016 Front. Plant Sci. 6:766.). The versatility of oomycetes, fungi and bacteria allows them to associate with plants in many ways depending on whether they are biotroph, hemibiotroph, necrotroph, or saprotroph. When interacting with a live organism, a microbe will ; invade its plant host and manipulate its metabolisms either detrimentally if it is a pathogen or beneficially if it is a symbiote. Deciphering secretomes became a crucial biological question when an increasing body of evidence indicated that secreted proteins were the main effectors initiating interactions, whether of pathogenic or symbiotic nature, between microbes and their plant hosts. Secretomics may help to contribute to the global food security and to the ecosystem sustainability by addressing issues in i) plant biosecurity, with the design of crops resistant to pathogens, ii) crop yield enhancement, for example driven by arbuscular mycorrhizal fungi helping plant hosts utilise phosphate from the soil hence increase biomass, and iii) renewable energy, through the identification of microbial enzymes able to augment the bio-conversion of plant lignocellulosic materials for the production of second generation biofuels that do not compete with food production. To this day, more than a hundred secretomics studies have been published on all taxa and the number of publications is increasing steadily. Secretory pathways have been described in various species of microbes and/or their plant hosts, yet the functions of proteins secreted outside the cell remain to be fully grasped. This Research Topic aims at discussing how secretomics can assist the scientists in gaining knowledge about the mechanisms underpinning plant-microbe interactions.