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Main conclusion: Hydrogen cyanide (HCN) is a ubiquitous gasotransmitter essential for regulating ROS metabolism and cellular redox balance. This modulation plays a crucial role in metabolic processes in higher plants and animals, highlighting HCN's importance in cellular signalling and stress response. Hydrogen cyanide (HCN) is synthesised in plants and animals and present ubiquitously in the environment. It is considered to be a gasotransmitter and is proposed to play a fundamental role in the origin of life. At concentrations higher than 100 µM, HCN is highly toxic to most aerobes, but at lower concentrations (below 100 µM) it serves as a signalling molecule in plants. The importance of this molecule in plant metabolism is highlighted by the fact that all higher plants produce HCN via various pathways. Given its toxicity, plants frequently store HCN as conjugates with sugars or lipids in vacuoles. HCN modulates the metabolism of reactive oxygen species (ROS), and this is also linked to the disruption of electron flow in the mitochondrial respiration chain. ROS are signalling compounds acting together with hormones in regulation of many physiological processes and typically modify the activity of enzymatic antioxidants by altering ROS levels, thereby impacting cellular redox potential. The aim of this review, therefore, is to describe the relationship between HCN activity and ROS metabolism, with a focus on higher plant systems in particular.

Main conclusion: Experimental transplantation of microspores and manipulation of locular fluid, in vivo, confirm a complex interplay between physicochemical processes and gene expression in shaping the 3-D ultrastructure of the developing exine. We aimed to understand the underlying mechanisms of development of the exine, the outer layer of the pollen wall, one of the most complex cell walls in plants. Control of the processes involved remained obscure until it became clear that the stages observed coincided, in essence, with the sequence of micellar self-assembling mesophases. To test this, a series of in vitro experiments were undertaken earlier (Gabarayeva et al., Ann Bot 123:1205-1218, 2019;Gabarayeva et al., New Phytol 225:1956-1973, 2020), in which exine-like patterns were generated in colloidal mixtures by self-assembly, without any genomic participation. The results of those experiments, carried out "in a vial", have shown that physicochemical interactions, phase separation and self-assembly are capable of generating exine-like patterns. The aim of the new experiments described here, conducted in living plants, was to alter the environment within the anther locule, observing any effects on the processes of exine ontogeny, and to see whether physicochemical interactions play the important role, suggested by in vitro experiments. In the first experiment, early microspore tetrads of Borago officinalis were transplanted into the anthers of Cucurbita maxima. In the second experiment, a surfactant mixture was injected into Cucurbita anthers to alter the environment of self-assembly. After several days, anthers were fixed and studied with TEM. The results confirm our earlier finding from in vitro studies, that-although gene expression in developing microspores and the anther is of fundamental importance-physicochemical forces also play a significant role in exine development. It is the interplay between controls that underpins the vast morphological diversity observed in sporoderms.

Main conclusion: Genomic selection (GS) is the preferred, non-transgenic strategy in conifer breeding, significantly accelerating genetic gain and overcoming limitations through early selection and the adoption of advanced, adaptive models. Genomic selection (GS) is a breeding method that uses molecular markers and phenotypic characteristics in the population genome to construct an associated genetic model, and then estimates the breeding value and predicts the phenotype of breeding populations with known genotypes but unknown phenotypes to achieve accurate and efficient genetic breeding. As an important part of the global forests, coniferous trees have high ecological and utilization value. However, due to their slow growth, large genome size, complex phenotypes, and weak foundational research, traditional phenotypic selection breeding is long and difficult. GS can complete the early selection of coniferous trees only based on the genotype after establishing the model, which not only saves the breeding time but also improves the genetic gain. It has become an important research direction in conifer breeding. This review first introduces the principle and method of GS, provides an overview of statistical models used in GS, then summarizes the research status of conifer GS. Finally, the factors affecting the implementation of GS for coniferous tree species were pointed out, and puts forward the prospect of the future development of conifer GS. This review provides strategies and ideas for further research on conifer GS breeding technology.

Main conclusion: A genetic complementation test using the Arabidopsis Pelota1 knock-out mutant revealed that pepy-1 derived from the begomovirus-resistant Capsicum is a leaky pelota allele with partial loss of function. We previously identified pepy-1, a begomovirus (family Geminiviridae) resistance gene in Capsicum, as a putative loss-of-function allele of pelota. Here, we performed a genetic complementation assay using the Arabidopsis Pelota1 knockout mutant SALK_124403, which is resistant to beet curly top virus (BCTV; family Geminiviridae, genus Curtovirus). Introduction of the susceptible allele (Pepy-1) restored susceptibility, whereas expression of the resistant allele (pepy-1) slightly compromised resistance, allowing limited viral replication but still conferring higher resistance than in Col-0. Thus, pepy-1 functions as a leaky allele that confers partial susceptibility, thereby diminishing-but not abolishing-resistance to BCTV. The delicate balance of this leaky allele confers virus resistance with minimal impact on growth, making it well-suited for use in breeding programs.

Main conclusion: To our knowledge, this study analyzed, for the first time, the mitogenome characteristics of Thinopyrum elongatum, including the identification of repetitive sequences in the mitogenome, RNA site editing, KaKs, and Pi and phylogenetic analysis. Thinopyrum elongatum is a perennial forage and ecological grass widely used in improving food crops and remediating saline-alkali soils in China owing to its characteristics, such as drought and waterlogging tolerance, salt-alkali resistance, and high yield with superior quality. Herein, we sequenced, annotated, and assembled the complete mitogenome of T. elongatum to understand its genetic diversity and phylogenetic relationships. The mitogenome length and GC content of T. elongatum are 390,404 bp and 44.38%, respectively. The mitogenome was annotated to contain 33 protein-coding genes (PCGs), 8 ribosomal RNA genes, 21 transfer RNA genes, and 2 pseudogenes. Codon use bias analysis revealed that T. elongatum preferentially used leucine (Leu), followed by serine (Ser) and arginine (Arg), respectively. Tryptophan (Trp) and methionine (Met) were the least frequently used. Among the 30 mitogenomic PCGs analyzed, 304 RNA editing sites were identified; among them, nad2 and ccmFn have been edited more frequently with 29 and 24 edits, respectively, confirming C-to-T RNA editing. Phylogenetic analysis indicated that T. elongatum and T. obtusiflorum were the most closely related species within the Thinopyrum genus, a conclusion supported by a phylogenetic tree constructed from 35 plant species. Moreover, genomic information from organelles can provide insights into plant phylogenies. The results of this study provide valuable data support for the subsequent in-depth analysis of the genome of T. elongatum. At the same time, it provides an important reference for exploring the mechanism of genetic variation, evolutionary history, and molecular breeding strategy of the genus Thinopyrum.

Main conclusion: Silencing the microtubule-associated protein PlWDL2 in herbaceous peony led to a decrease in stem strength by affecting xylem development. Stem strength is an important factor affecting the quality of herbaceous peony (Paeonia lactiflora Pall.) cut flowers. To investigate the effect of microtubule-associated proteins on P. lactiflora stem strength, we identified PlWDL2, a WAVE-DAMPENED 2/WAVE-DAMPENED 2-LIKE (WVD2/WDL) family gene encoding a 340 amino acid protein with conserved KLEEK motif. Quantitative real-time PCR (qRT-PCR) revealed that PlWDL2 expression was progressively upregulated during P. lactiflora stem development. In vitro co-sedimentation assays confirmed microtubule-binding capacity of PlWDL2 and its intrinsically disordered regions (IDRs) though IDRs exhibited attenuated binding correlated with shorter hydrophobic patches. Additionally, the PlWDL2-silenced P. lactiflora exhibited decreased stem strength. Further microstructure observation of the stems showed that xylem thickness, number of layers, and the proportion of xylem area and xylem cell area in the PlWDL2-silenced P. lactiflora were significantly reduced. These findings demonstrate that the microtubule-associated protein PlWDL2 enhances stem strength in P. lactiflora by promoting xylem development. This study lays a foundation for future studies on the mechanism of P. lactiflora stem development from the relationship between microtubule-associated proteins and microtubules.

Main conclusion: Soil nutrients and associated bacterial shifts revealed that positive plant-soil feedback enables Conyza canadensis to colonize metal-contaminated soil. The identified thresholds provide guidance for effective weed management under environmental stress. Invasion by non-native plants can trigger a self-promoting mechanism that facilitates their invasion by affecting soil nutrients and microbiota. Notably, the invasive Conyza canadensis (L.) Cronquist tends to colonize metal-contaminated areas. This study investigated how its progressive invasion affected abiotic and biotic properties in cadmium (Cd) and lead (Pb) co-contaminated soil. Different invasion stages were simulated by varying the relative densities of C. canadensis and the non-invasive Lactuca indica Linn. Both abiotic and biotic components were significantly altered as the invasion intensity increased. Along the invasion gradient of C. canadensis, the soil contents of total phosphorus (TP), available phosphorus (AP), available potassium (AK), and soil organic matter (SOM), the structure of soil bacterial communities, and the accumulation of heavy metals in plant roots were altered. The relative abundances of key bacterial taxa associated with nutrient cycling, such as the phyla Gemmatimonadota and Planctomycetota, and the families Gemmatimonadaceae, Burkholderiaceae, Micrococcaceae, and Sphingomonadaceae, were shifted. Importantly, critical thresholds for abrupt nutrient shifts were identified through the discontinuous changes of AK and AP when C. canadensis invasion levels reached 38% and 48%, respectively. These nutrient thresholds coincided with shifts in the relative abundance of bacterial taxa involved in nutrient cycling, such as Micrococcaceae (OTU68) and Solibacteraceae (OTU208). The triggering of changes in the abiotic and biotic components of the soil system may represent crucial functional traits that promote positive feedbacks to increase the invasiveness of C. canadensis. These interactions support the ecological dynamics and successful colonization of C. canadensis in heavy metal-contaminated soil, and the identified invasion thresholds can provide guidance for effective weed management under environmental stress.

Main conclusion: Wheat cultivars' contradictory responses to drought stress regarding dry matter remobilization are primarily due to differences in assimilate partitioning to mobilizable non-structural carbohydrates in the stem. Accumulation and remobilization of stem reserves are crucial for maintaining wheat yield stability under drought stress (DS). Cultivars respond differently to DS in dry matter remobilization (DMR), but the reasons are unclear. This study aimed to identify factors driving cultivar-specific variation in DMR by examining two wheat cultivars with contrasting drought tolerance and DMR characteristics under well-watered (70% field capacity) and DS (50% field capacity, imposed from stem elongation onward) conditions. Data showed that DS significantly improved DMR efficiency and the contribution of stem reserves to grain yield by 26.78 and 44.53% in Shabrang (drought-resistant) and by 13.97 and 26.80% in Dez (drought-sensitive), respectively. Dez demonstrated a 36.04% reduction in DMR, associated with severe source limitations and reduced sink size, while Shabrang increased by 5.40% under DS. Improved DMR in Shabrang was initially linked to a 12.39% increase in the proportion of stem water-soluble carbohydrates (WSC) to stem dry weight, a pattern not observed in Dez. Shabrang also exhibited better chlorophyll retention and Fv/Fm values, a larger green flag leaf area, greater WSC accumulation, higher endosperm cell division and number, and a faster grain-filling rate. In addition, the relative expression of sucrose-fructan 6-fructosyltransferase and fructan 1-exohydrolase w3 was higher in Shabrang during the examined periods. Overall, differences in cultivars' DMR under DS are mainly driven by variations in assimilate partitioning, source-sink strength, and carbohydrate metabolism. Enhancing these traits could improve DMR, stabilize wheat yield under water-limited conditions, and support sustainable crop improvement strategies in the face of climate change.

Main conclusion: We systematically evaluated three key determinants affecting prediction accuracy and the algorithm performance differences based on fifteen state-of-the-art GP methods, and found LSTM suitable for capturing additive and epistatic effects. Genomic prediction (GP) has been developed as an important method supporting crop breeding. By utilizing the phenotype values result from GP, breeders could make decisions in the seedling stage that consequently benefit for cost saving. In recent years, machine learning emerged as an efficient technology to solve modeling problems in many fields, including crop breeding. However, numerous modeling approaches have hindered the application of GP since breeders struggle to choose. Therefore, a comprehensively methodological research with guiding significance is extremely necessary. In the present study, we systematically evaluated three key determinants affecting prediction accuracy and the algorithm performance differences based on fifteen state-of-the-art GP methods. As for genomic feature processing, we found feature selection (SNP filtering approach) performed better than feature extraction (PCA method). Specifically, the feature relationship dependent methods (GBLUP, RNN, and LSTM) as well as DNN architecture showed superior performance with feature selection. Marker density analysis showed positive correlation with prediction accuracy in a limited threshold. Comparison on effect of population size demonstrated a positive correlation between trait genetic complexity and the optimal population size required. By testing fifteen modeling methods, we found LSTM network displayed superior performance, achieving the highest average STScore (0.967) across six datasets. Further research using all cell states or the latest cell states of LSTM inputs demonstrated its architecture particularly adept with capturing additive and epistatic QTL effects among SNPs. In conclusion, our findings provide basic principles for implementing GP in breeding project to maximize prediction accuracy while maintaining cost-effectiveness.

Main conclusion: The study demonstrates that Macrocoma orthotrichoides employs a poikilochlorophyllous strategy and exhibits rapid photosynthetic recovery, providing novel biochemical and fluorescence-based evidence of desiccation tolerance in this species.

Conclusion: Mosses are poikilohydric plants that activate defence mechanisms to protect their tissues and metabolism from dehydration-induced damage, particularly by counteracting the generation/accumulation of reactive oxygen species (ROS). In this study, we evaluate the responses of Macrocoma orthotrichoides gametophytes to dehydration by analysing chlorophyll a fluorescence parameters, metabolite accumulation, and antioxidant enzyme activities in response to ROS production under varying humidity conditions. Fresh gametophyte samples were exposed to controlled moisture regimes, and biochemical analyses revealed that the activity of antioxidant enzymes and proline levels fluctuated in response to dehydration; however, these changes did not fully mitigate oxidative stress and ROS accumulation. Changes in photosynthetic pigment concentrations mirrored enzymatic activity, being consistent with humidity conditions. The decrease in chlorophyll and carotenoid levels during desiccation indicates a poikilochlorophyllous strategy in M. orthotrichoides, with pigments and thylakoid structures being restored upon rehydration. Fluorescence analysis demonstrated that this species tolerates intense dehydration and rapidly regains photosynthetic capacity upon rehydration. Overall, our findings indicate that M. orthotrichoides possesses a suite of biochemical, enzymatic, and physiological adaptations that enable survival and recovery in fluctuating moisture environments, thereby advancing our understanding of desiccation tolerance and photosynthetic resilience in mosses.