Explore the vast range of titles available.

Background Daye No.3 is a novel cultivar of alfalfa ( Medicago sativa L.) that is well suited for cultivation in high-altitude regions such as the Qinghai‒Tibet Plateau owing to its high yield and notable cold resistance. However, the limited availability of transcriptomic information has hindered our investigation into the potential mechanisms of cold tolerance in this cultivar. Consequently, we conducted de novo transcriptome assembly to overcome this limitation. Subsequently, we compared the patterns of gene expression in Daye No. 3 during cold acclimatization and exposure to cold stress at various time points. Results A total of 15 alfalfa samples were included in the transcriptome assembly, resulting in 141.97 Gb of clean bases. A total of 441 DEGs were induced by cold acclimation, while 4525, 5016, and 8056 DEGs were identified at 12 h, 24 h, and 36 h after prolonged cold stress at 4 °C, respectively. The consistency between the RT‒qPCR and transcriptome data confirmed the accuracy and reliability of the transcriptomic data. KEGG enrichment analysis revealed that many genes related to photosynthesis were enriched under cold stress. STEM analysis demonstrated that genes involved in nitrogen metabolism and the TCA cycle were consistently upregulated under cold stress, while genes associated with photosynthesis, particularly antenna protein genes, were downregulated. PPI network analysis revealed that ubiquitination-related ribosomal proteins act as hub genes in response to cold stress. Additionally, the plant hormone signaling pathway was activated under cold stress, suggesting its vital role in the cold stress response of alfalfa. Conclusions Ubiquitination-related ribosomal proteins induced by cold acclimation play a crucial role in early cold signal transduction. As hub genes, these ubiquitination-related ribosomal proteins regulate a multitude of downstream genes in response to cold stress. The upregulation of genes related to nitrogen metabolism and the TCA cycle and the activation of the plant hormone signaling pathway contribute to the enhanced cold tolerance of alfalfa.

Main conclusion This paper highlights the need for innovative approaches to enhance cold tolerance. It underscores how genome-editing tools can deepen our understanding of genes involved in cold stress. Cold stress is a significant abiotic factor in high-altitude regions, adversely affecting plant growth and limiting crop productivity. Plants have evolved various mechanisms in response to low temperatures that enable resistance at both physiological and molecular levels during chilling and freezing stress. Several cold-inducible genes have been isolated and characterized, with most playing key roles in providing tolerance against low-temperature stress. However, many plants fail to survive at low temperatures due to the absence of cold acclimatization mechanisms. Conventional breeding techniques, such as inter-specific or inter-genic hybridization, have had limited effectiveness in enhancing the cold resistance of essential crops. Thus, it is crucial to develop crops with improved adaptability, high yields and resistance to cold stress using advanced genomic approaches. The current availability of gene editing tools offers the opportunity to introduce targeted modifications in plant genomes efficiently, thereby developing cold-tolerant varieties. This review discusses advancements in gene editing tools, including zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), clustered regularly interspaced short palindromic repeats (CRISPR)/ CRISPR -associated protein 9 (Cas9)/Cas12a(Cpf1), prime editing (PE) and retron library recombineering (RLR). We focus specifically on the CRISPR/Cas system, which has garnered significant attention in recent years as a groundbreaking tool for genome editing across various species. These techniques will enhance our understanding of molecular interactions under low-temperature stress response and highlight the progress of genome editing in designing future climate-resilient crops.

Abstract Saccharomyces pastorianus is a natural yeast evolved from different hybridization events between the mesophilic S. cerevisiae and the cold-tolerant S. eubayanus. This complex aneuploid hybrid carries multiple copies of the parental alleles alongside specific hybrid genes and encodes for multiple protein isoforms which impart novel phenotypes, such as the strong ability to ferment at low temperature. These characteristics lead to agonistic competition for substrates and a plethora of biochemical activities, resulting in a unique cellular metabolism. Here, we investigated the transcriptional signature of the different orthologous alleles in S. pastorianus during temperature shifts. We identified temperature-dependent media-independent genes and showed that 35% has their regulation dependent on extracellular leucine uptake, suggesting an interplay between leucine metabolism and temperature response. The analysis of the expression of ortholog parental alleles unveiled that the majority of the genes expresses preferentially one parental allele over the other and that S. eubayanus-like alleles are significantly over-represented among the genes involved in the cold acclimatization. The presence of functionally redundant parental alleles may impact on the nature of protein complexes established in the hybrid, where both parental alleles are competing. Our expression data indicate that the majority of the protein complexes investigated in the hybrid are likely to be either exclusively chimeric or unispecific and that the redundancy is discouraged, a scenario that fits well with the gene balance hypothesis. This study offers the first overview of the transcriptional pattern of S. pastorianus and provides a rationalization for its unique industrial traits at the expression level.

Cryopreservation is a crucial technique for the long-term ex situ conservation of plant genetic resources, particularly in the context of global biodiversity decline. This process entails freezing biological material at ultra-low temperatures using liquid nitrogen, which effectively halts metabolic activities and preserves plant tissues over extended periods. Over the past seven decades, a plethora of techniques for cryopreserving plant materials have been developed. These include slow freezing, vitrification, encapsulation dehydration, encapsulation–vitrification, droplet vitrification, cryo-plates, and cryo-mesh techniques. A key challenge in the advancement of cryopreservation lies in our ability to understand the molecular processes underlying plant freezing tolerance. These mechanisms include cold acclimatization, the activation of cold-responsive genes through pathways such as the ICE–CBF–COR cascade, and the protective roles of transcription factors, non-coding RNAs, and epigenetic modifications. Furthermore, specialized proteins, such as antifreeze proteins (AFPs) and late embryogenesis abundant (LEA) proteins, play crucial roles in protecting plant cells during freezing and thawing. Despite its potential, cryopreservation faces significant challenges, particularly in standardizing protocols for a wide range of plant species, especially those from tropical and subtropical regions. This review highlights the importance of ongoing research and the integration of omics technologies to improve cryopreservation techniques, ensuring their effectiveness across diverse plant species and contributing to global efforts regarding biodiversity conservation.

Actinidia arguta ( A. arguta , kiwiberry) is a perennial deciduous vine with a strong overwintering ability. We hypothesized that trehalose metabolism, which plays a pivotal role in the stress tolerance of plants, may be involved in the cold acclimatization of A. arguta . Transcriptome analysis showed that the expression of AaTPPA , which encodes a trehalose-6-phosphate phosphatase (TPP), was upregulated in response to low temperatures. AaTPPA expression levels were much higher in lateral buds, roots, and stem cambia than in leaves in autumn. In AaTPPA -overexpressing (OE) Arabidopsis thaliana ( A. thaliana ), trehalose levels were 8–11 times higher than that of the wild type (WT) and showed different phenotypic characteristics from WT and OtsB ( Escherichia coli TPP ) overexpressing lines. AaTPPA -OE A. thaliana exhibited significantly higher freezing tolerance than WT and OtsB -OE lines. Transient overexpression of AaTPPA in A. arguta leaves increased the scavenging ability of reactive oxygen species (ROS) and the soluble sugar and proline contents. AaERF64 , an ethylene-responsive transcription factor, was induced by ethylene treatment and bound to the GCC-box of the AaTPPA promoter to activate its expression. AaTPPA expression was also induced by abscisic acid. In summary, the temperature decrease in autumn is likely to induce AaERF64 expression through an ethylene-dependent pathway, which consequently upregulates AaTPPA expression, leading to the accumulation of osmotic protectants such as soluble sugars and proline in the overwintering tissues of A. arguta .

Cold acclimatization in tropical region-originated plants involves complex gene expression reprogramming to adapt to fluctuating temperatures. However, the molecular mechanisms and gene networks regulating cold tolerance in king grass remain largely unknown. To address this, we established a full-length reference transcriptome of king grass to enhance assembly quality and performed multiple time-point transcriptomic analyses following cold treatment at 4°C. Differentially expressed genes (DEGs) and transcription factors (TFs) involved in cold stress response were identified and analyzed through clustering and co-expression network analysis. A total of 13,056 DEGs were identified and classified into nine clusters via k-means analysis. The cold response exhibited three distinct phases: early (before 3 h), middle (6-24 h), and late (48-72 h). Early-responsive genes were enriched in glycolipid metabolism and photosynthesis, middle-stage genes in carbohydrate metabolism, and late-stage genes in cold stress, osmotic stress, and endogenous stimuli responses. Key regulators of the ICE-CBF-COR signaling module, including 13 positive and negative regulators, were identified. The co-expression network further revealed mutual regulatory interactions within this module, highlighting its role in cold stress adaptation. Our findings provide insights into the cold tolerance mechanisms of king grass, offering a genetic basis for modifying cold stress regulators. This research contributes to the broader understanding of low-temperature adaptive mechanisms in tropical plants and supports future breeding strategies for improved cold tolerance.

Summary 11 Introduction 12 Photoprotection by flexible thermal energy dissipation 13 Photoprotection by sustained thermal dissipation 14 Association of sustained photoprotection with photoinhibition, carbon export capacity and plant growth 18 Acknowledgements 19 References 19 This review places photoprotection into the context of ecology and species diversity. The focus is on photoprotection via the safe removal - as thermal energy - of excess solar energy absorbed by the light collecting system, which counteracts the formation of reactive oxygen species. An update on the surprisingly complex, multiple variations of thermal energy dissipation is presented, placing these different forms into ecological and genetic contexts. Zeaxanthin-facilitated, flexible thermal dissipation associated with the PsbS protein and controlled by the trans-thylakoid pH gradient apparently occurs ubiquitously in plants, and can become sustained (and thus less flexible) at low temperatures. Long-lived, slow-growing plants with low intrinsic capacities for photosynthesis have greater capacities for this flexible dissipation than short-lived, fast-growing species. Furthermore, potent, but inflexible (zeaxanthin-facilitated) thermal dissipation, prominent in evergreen species under prolonged environmental stress, is characterized with respect to the involvement of photosystem II core rearrangement and/or degradation as well as the absence of control by trans-thylakoid pH and, possibly, PsbS. A role of PsbS-related proteins in photoprotection is discussed.

Snow algae play crucial roles in cold ecosystems, however, many aspects related to their biology, adaptations and especially their diversity are not well known. To improve the identification of snow algae from colored snow, in the present study we used a polyphasic approach to describe a new Antarctic genus, Chlorominima with the species type Chlorominima collina . This new taxon was isolated of colored snow collected from the Collins Glacier (King George Island) in the Maritime Antarctic region. Microscopy revealed biflagellated ellipsoidal cells with a rounded posterior end, a C-shaped parietal chloroplast without a pyrenoid, eyespot, and discrete papillae. Several of these characteristics are typical of the genus Chloromonas , but the new isolate differs from the described species of this genus by the unusual small size of the cells, the presence of several vacuoles, the position of the nucleus and the shape of the chloroplast. Molecular analyzes confirm that the isolated alga does not belong to Chloromonas and therefore forms an independent lineage, which is closely related to other unidentified Antarctic and Arctic strains, forming a polar subclade in the Stephanosphaerinia phylogroup within the Chlamydomonadales. Secondary structure comparisons of the ITS2 rDNA marker support the idea that new strain is a distinct taxon within of Caudivolvoxa . Physiological experiments revealed psychrophilic characteristics, which are typical of true snow algae. This status was confirmed by the partial transcriptome obtained at 2°C, in which various cold-responsive and cryoprotective genes were identified. This study explores the systematics, cold acclimatization strategies and their implications for the Antarctic snow flora.

Rice cultivation on paddy soil is commonly associated with emissions of methane, a greenhouse gas, but rice varieties may differ in their actual level of emissions. This study analysed methane emissions associated with 22 distinct rice genotypes, using gas chromatography, and identified the cultivar Heijing 5 from northern China as a potential low-methane rice variety. To confirm this and to examine whether Heijing 5 can perform similarly at higher latitudes, Heijing 5 was cultivated in field trials in China (lat. 32° N) and Sweden (lat. 59° N) where (i) methane emissions were measured, (ii) methanogen abundance in the rhizosphere was determined using quantitative PCR, and (iii) the concentrations of nutrients in water and of heavy metals in rice grain and paddy soil were analysed. The results demonstrated that the low-methane rice cultivar Heijing 5 can successfully complete an entire growth period at high-latitude locations such as central Sweden. Massively parallel sequencing of mRNAs identified candidate genes involved in day length and cold acclimatisation. Cultivation of Heijing 5 in central Sweden was also associated with relatively low heavy metal accumulation in rice grains and lowered nutrient losses to neighbouring water bodies.

Kaare Rodahl, a scientist with the US Air Force’s Arctic Aeromedical Laboratory, spent much of the 1950s traveling to villages in the Alaskan Arctic to conduct research on cold acclimatization. Four decades later, it was discovered that during one such study, he had administered radioactive isotopes of iodine-131 to over one hundred Alaska Native research subjects without their knowledge or consent. This news broke just as Alaska Native communities were attempting to recover from a series of revelations surrounding other instances of Cold War radiation exposure. In response, two major federal investigations attempted to determine whether Rodahl had adhered to ethical regulations and whether his actions could be expected to have a lasting health impact on former research subjects. The National Research Council, framing the study as a singular event in the Cold War past, found that research subjects had been ‘wronged, but not harmed’. The North Slope Borough, a powerful Alaska Native municipal government, countered this finding with their own investigation, which identified both the study and the subsequent federal inquiries as facets of the still-unfolding process of American settler colonialism in Alaska. In doing so, the North Slope Borough contested the authority of federal agencies to set the terms by which ethics could be retrospectively judged. This article argues that exploring how competing ethical regimes represent the relationship between violence and time can help us better understand how institutionalized bioethics reproduces settler colonial power relations.