Planta最新文献

Main conclusion: Gibberellins promote differentiated root and shoot responses in growth, morphology, and carbon allocation. Gibberellins (GAs) are plant hormones that are produced in young tissues and organs, acting locally in growing shoots and roots or being transported to other organs. The role of GAs in root development was first investigated decades ago using plants severely deficient in GA biosynthesis. However, only few studies have examined root metabolism in plants with reduced GA levels and evaluated its association with root growth and morphology. Furthermore, the signaling between the root and shoot systems plays a key role in coordinating plant growth and development. Therefore, this study aimed to assess the impact of endogenous alterations in GA levels on tomato mutants exhibiting mild (gibberellin deficient-3, gib3), intermediate (gib2), and high (gib1) GA deficiency on root and shoot growth, morphology, respiratory metabolism, and labeled carbon allocation. The low GA content exerted an effect on shoot growth and morphology, which, surprisingly, led to minor changes in the mutant roots. The gib2 and gib1 mutants exhibited higher proportions of thick roots than the wild-type and gib3, but the growth of roots with smaller diameters was most pronounced in these genotypes. The carbohydrate oxidation was influenced by a reduction in GA biosynthesis within mutant leaves and roots. In addition, the differential sensitivity to GA by each organ likely contributed to variations in sugar accumulation. Together, these results indicate that shoot tissues exhibit a distinct response compared to root tissues, suggesting a decoupling of root growth and carbon allocation from shoot growth and development in GA-deficient plants. This observation points to a key role for GA in orchestrating the growth of both shoots and roots.

Main conclusion: Inoculation with Pseudomonas simiae WCS417 improves cucumber growth under Fe deficiency conditions and induces iron-deficiency responses, making it a promising candidate for sustainable biofertilization strategies in dicot plants. Iron (Fe) deficiency poses a significant agronomic challenge in calcareous soils, particularly affecting dicot plants. Conventional production methods rely heavily on high-yielding varieties and the application of substantial amounts of agrochemicals, leading to considerable environmental concerns. In this context, leveraging the potential of beneficial rhizosphere microorganisms as biofertilizers represents a highly promising and environmentally sound alternative to chemical fertilizers. This study aims to investigate the efficacy of the nonpathogenic strain Pseudomonas simiae WCS417 in eliciting Fe deficiency responses in cucumber plants, along with its impacts on plant growth and Fe chlorosis. Conducted under hydroponic conditions, our experiments reveal compelling outcomes. Root inoculation of cucumber plants with P. simiae significantly enhances plant growth while concurrently mitigating Fe chlorosis symptoms over successive cultivation days. The inoculation with this bacterium induces acidification in the subapical zone of cucumber roots, facilitating Fe solubility in the rhizosphere. Additionally, P. simiae triggers the upregulation of Fe-related genes in inoculated plants, even under Fe sufficiency. In conclusion, P. simiae emerges as a potent enhancer of Fe deficiency responses in cucumber plants. Its ability to promote growth, enhance Fe solubility through rhizosphere acidification, and alleviate Fe chlorosis underscores its potential as an effective biofertilizer for a sustainable Fe nutrition of dicot plants.

This study aims to elucidate the mechanisms of carbon metabolism regulation involved in the solidification of bamboo culms in Phyllostachys heteroclada f. solida. Differentially expressed genes (DEGs) between Ph. heteroclada f. solida and hollow-stemmed variant Ph. heteroclada were identified by transcriptome sequencing. Enrichment analysis of GO and KEGG pathways revealed pronounced divergence in starch-sucrose metabolism and phenylpropanoid biosynthesis pathways. Key starch enzyme genes (e.g., PYG and AMY) were downregulated, while genes involved in sucrose metabolism (e.g., INV and SUS) were upregulated in Ph. heteroclada f. solida. Concurrently, lignin biosynthesis genes (e.g., PAL, C4H, and 4CL) were downregulated, whereas genes associated with cell wall synthesis substances such as pectin and cellulose were upregulated. Non-structural carbohydrate accumulation in Ph. heteroclada f. solida was consistent with these gene expression patterns. The study identified key differences in carbon metabolism pathways between Ph. heteroclada f. solida and Ph. heteroclada, demonstrating that the regulation of carbon metabolism genes plays an important role in culm solidification. These findings provide a foundational understanding of the molecular mechanisms underlying bamboo stem variation and offer insights for future bamboo breeding efforts.

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.