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Unraveling the Molecular and Biochemical Mechanisms of Cold Stress Tolerance in Rice
Published in Hasanuzzaman Mirza, Nahar Kamrun, Fujita Masayuki, Oku Hirosuke, Tofazzal M. Islam, Approaches for Enhancing Abiotic Stress Tolerance in Plants, 2019
Joseph Msanne, Lymperopoulos Panagiotis, Roel C. Rabara, Supratim Basu
Ubiquitin, found in both cytosol and the nucleus of eukaryotic cells, can be covalently bound to other proteins to regulate the stability, function, or location of the modified protein. Ubiquitin is recognized by specific receptors that contain one or more ubiquitin-binding domains (Dikic et al., 2009). Usually, these domains bind to ubiquitin with low affinity, which makes this bond highly dynamic. Therefore, the ubiquitin coupling and uncoupling system mediates several cell processes involved in the growth and development of plants, such as embryogenesis, photomorphogenesis, and hormone regulation. Stress caused by extreme temperatures disturbs the cell homeostasis, resulting in a delay in plant development, as it affects seed germination, photosynthesis, respiration, and plasma membrane stability. E3 ubiquitin ligases play a crucial role in the specific recognition of appropriate target proteins and the attachment of a poly-ubiquitin chain (Chen and Hellmann, 2013). They are divided into two groups based on their structures. The U-box E3 ubiquitin ligases contain a modified Really Interesting New Gene (RING) domain and widely exist in eukaryotic organisms. An increased number of U-box proteins (PUBs) in higher plants might indicate their important role in diverse cellular processes. Research carried out by Byun et al. (2017) has shown that two homologous U-box type E3 ubiquitin ligases, OsPUB2 and OsPUB3, function in coordination to improve cold stress tolerance. Byun et al. (2017) proved this by overexpression analysis where it was observed that transgenic rice plants showed improved cold tolerance assessed through chlorophyll content or ion leakage. Another research has shown that silencing OsSRFP1 (stress-related RING finger protein 1) leads to improved cold tolerance as opposed to the overexpressing lines, suggesting a negative role in cold tolerance. From the research of Fang et al. (2015), it was concluded that the cold tolerance of RNAi lines was achieved primarily through improved antioxidant defense machinery (Fang et al., 2016).
Cadmium stress in plants: A critical review of the effects, mechanisms, and tolerance strategies
Published in Critical Reviews in Environmental Science and Technology, 2022
Taoufik El Rasafi, Abdallah Oukarroum, Abdelmajid Haddioui, Hocheol Song, Eilhann E. Kwon, Nanthi Bolan, Filip M. G. Tack, Abin Sebastian, M. N. V. Prasad, Jörg Rinklebe
Proline is a non-essential amino acid (Kumar et al., 2017) biosynthesized in chloroplasts and plant-cell cytoplasm (Szepesi & Szollosi, 2018; Verbruggen & Hermans, 2008) from an ornithine precursor and glutamate with the involvement of various genes such as ornithine-δ-aminotransferase, pyrroline-5-carboxylate reductase, and pyrroline-5-carboxylate synthetase (Kishor et al., 2015; Lehmann et al., 2010). It plays various roles during plant development, flowering, and seed development (Lehmann et al., 2010). Plants may synthetize proline in either the absence or presence of abiotic stress (e.g., metal exposure) (Kishor et al., 2015). It has been reported that in Cd exposure, proline content increases in different plant species, including Solanum nigrum (Sun et al., 2007), Arachis hypogaea (Dinakar et al., 2008), cucumber (Semida et al., 2018), bean (Rady et al., 2019), and hackberry (Celtis australis) (Hatamian et al., 2020). Proline is an important metabolite for plant adaptation, protection, and tolerance to Cd stress. Accumulation of proline in plants is recognized as a strategy to counteract Cd stress by adjusting osmotic potential, stabilization of membrane structures (Amari et al., 2017; Semida et al., 2018; Zouari et al., 2016), and reduction of oxidative stress (Rady et al., 2019; Singh, Pratap Singh et al., 2015). Olive plants (Olea europaea) exposed to Cd stress demonstrated an increase of proline content in both roots and leaves and increased Cd content in Cd-treated plants (Zouari et al., 2016). The latter authors demonstrated that application of exogenous proline leads to the increase of proline content, a notable decrease of Cd content in olive roots and leaves, and a decrease of oxidative stress indicators (H2O2, TBARS, and EL); however, an increase of gas exchange parameters, photosynthetic pigment content, and micronutrients (Ca, Mg, and K) was observed. Moreover, the protective role of proline includes formation of a nontoxic Cd-proline complex (Rehman et al., 2017; Sun et al., 2007), acting as a source of C and N, and activating the antioxidant system (Dinakar et al., 2008; Zouari et al., 2016).
Towards understanding the environmental and climatic changes and its contribution to the spread of wildfires in Ghana using remote sensing tools and machine learning (Google Earth Engine)
Published in International Journal of Digital Earth, 2023
Kueshi Sémanou Dahan, Raymond Abudu Kasei, Rikiatu Husseini, Mohammed Y. Said, Md.Mijanur Rahman
distribution as in the following equation: With is the variance of statistic S. Thus, a positive Z value indicates an increasing trend, whereas a negative value indicates that the trend is decreasing. Temperature and Wind speedAccording to Hatfield and Prueger (2015), temperature is one of the main factors influencing the rate of plant development. The higher temperatures predicted by climate change and the risk of more extreme thermal events will have an impact on plant productivity (Hatfield and Prueger 2015). The latter dries them out and makes them fragile in the face of water stress. Thus, maximum, minimum and average temperatures were considered (monthly) in our assessment through a descriptive approach and the Mann-Kendall test as well. For Wind speed, the same approach was used. In the context of burnt area dynamics, the wind is a key parameter because, according to Guiguindibaye, Belem, and Boussim (2013), fire spread is closely linked to wind speed and vegetation height Relative humidityRelative humidity (RH) is expressed in percentage (%) and is the ratio of the amount of water in the air (absolute humidity) to the maximum amount it can hold at a given temperature before condensing. It is influenced by temperature variation. In the present work, the data was computed through the GEE platform using the Clausius–Clapeyron approach due to the lack of relative humidity (Table 4) data for the whole period under consideration. Thus, the specific humidity was used for its calculation. It was then analysed through a descriptive approach (monthly analysis over the study period) and the Mann-Kendall test as well. According to Clapeyron’s (1834) and Clausius’s (1850) approach, Relative humidity is just , the ratio of vapour pressure to saturation vapour pressure or the ratio of the mass mixing ratios of water vapour to actual and saturation values. Then, the specific humidity can be expressed as the mass mixing ratio of water vapour in the air, defined as follows: Relative humidity can be expressed as the ratio of water vapour mixing ratio to saturation water vapour mixing ratio, , with: