Planta最新文献

Key message: Main conclusion This review provides a comprehensive overview of microbial-derived inducers of disease resistance in plants, elucidates their mode of action, and offers prospects for their practical application. Plants are constantly facing various pests and pathogens such as fungi, bacteria, viruses, insects, nematodes, etc., leading to an important loss in crop productivity. While conventional pesticides are effective in eliminating these pathogens, their use poses serious environmental and health risks. Plants can combat these pathogens by activating different facets of their innate defense mechanisms. In this context, several microbial-derived inducers enable plants to resist various pathogens by rapidly and intensely activating host-defense reactions after invader recognition. These inducers include oligosaccharides, lipids, peptides, and proteins, which can activate the plant immune system. They trigger various signaling pathways that commonly induce reactive oxygen species (ROS) generation, phytoalexin production, and pathogenesis-related (PR) proteins biosynthesis. This review outlines various microbial inducers that boost plant disease resistance, elucidating their basic modes of action. Moreover, it engages with the latest methodologies, and prospects for developing and applying microbial-derived inducers.

Main conclusion: This review highlights aboveground living plant-based methane production and evaluates its quantities in terrestrial ecosystems globally. The estimated quantities collectively explain only ~ 2% of aboveground living plant-based methane emissions. Aboveground living plant-based methane (CH₄) processes and fluxes have gained increasing attention over the last decades. However, aboveground living plant-based CH₄ production and its quantities in terrestrial ecosystems are not well known. For profoundly understanding the CH₄ processes and fluxes, we need to clarify aboveground living plant-based CH₄ production and evaluate its quantities in terrestrial ecosystems. The vertical pattern (from rhizosphere to canopy of plants, and vice versa) of the CH₄ production shows prominent variability across the various types of vegetated ecosystems, with especially large uncertainties in forests, and may moderately influence the vertical patterns of living plant-based CH₄ oxidation and emissions. Aboveground living plant-based CH₄ can be produced by microbial and non-microbial mechanisms. Microbial CH₄ is primarily produced in wet vegetation niche, while non-microbial CH₄ is typically produced in plant foliage under environmental stressors. The global aboveground living plant-based CH₄ production is summarized at the quantities of about 2.26 (1.11-3.87) Tg CH₄ yr^-1, and their uncertainties and complexities are further discussed. We suggest that aboveground living plant-based CH₄ production and its relationships with aboveground living plant-based CH₄ transport and emissions require more research, particularly within forest ecosystems.

Main conclusion: Far-red light is stressful to Marchantia polymorpha and reduces the efficiency of photosystem II. In response, Marchantia reorganizes the chloroplast ultrastructure, forming Rubisco condensate regions to physicochemically concentrate CO₂. The light spectral composition is one of the key photomorphogenesis factors. Far-red light (FRL) resulted in marked changes in the morphology of Marchantia polymorpha chloroplasts. However, most aspects of this photomorphogenesis remain unexplored, and this work is devoted to elucidating their nature. We studied in vitro cultured M. polymorpha under FRL or wide spectral range illumination. Transmission electron microscopy and Au-immunolabeling were used for analysis. Gene expression and protein quantification were performed via RT‒PCR and Western blotting. FRL causes the appearance of non-membrane formation in the chloroplast, which has not been previously described for M. polymorpha. This region is enriched in ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and is surrounded by starch grains. FRL negatively regulates the accumulation of Rubisco in M. polymorpha at the transcriptional level. Our study revealed that, under FRL action, M. polymorpha experiences a marked decrease in the key enzyme involved in CO₂ assimilation, Rubisco. At the same time, Rubisco condensate structures are formed in chloroplasts, which can be considered a compensatory strategy for the realization of the CO₂ concentrating mechanism, which is widely known in phylogenetically close groups.

Main conclusion: Methanol proved to be the most efficient solvent for pigment extraction using pressurized liquid extraction, while extraction temperature and static time critically influenced both the yield and stability of the pigments. Photosynthetic pigments, particularly chlorophylls and carotenoids, are central to plant physiology and are increasingly valued for their nutritional and functional benefits in the human diet. However, accurate quantification of these compounds remains challenging due to their sensitivity to degradation during sample preparation. The present study aimed to optimize extraction protocols for chlorophylls (a, b) and two major leaf carotenoids (β-carotene and lutein) from fresh parsley leaves, with a focus on balancing yield and stability. The effects of solvent type, extraction temperature, static extraction time, and number of extraction cycles were systematically evaluated using pressurized liquid extraction (PLE) and compared with conventional solvent extraction. High-performance liquid chromatography with diode-array detection was employed for quantitative analysis. Methanol consistently outperformed acetone as a solvent, yielding significantly higher recoveries of both chlorophylls and carotenoids. Optimal performance was observed under two distinct PLE conditions: three 5-min cycles at 100 °C, which provided a balanced recovery of pigments with low chlorophyll a degradation, and a single 5-min extraction at 125 °C, which maximized carotenoid yields but accelerated chlorophyll a breakdown. Extractions at 150 °C and prolonged dimethyl sulfoxide treatment resulted in substantial chlorophyll a degradation, highlighting the need for carefully controlled conditions. Compared with conventional solvent extraction, PLE reduced extraction time and offered superior yields for β-carotene and lutein. The results underscore the trade-offs inherent in pigment extraction and demonstrate that PLE, when optimized, provides a robust and efficient tool for evaluating the nutritional quality of fresh leafy vegetables. These findings may serve as a methodological foundation for both research applications and the development of more reliable, industry-relevant quality assessment protocols.

Main conclusion: Soybean inflorescence architecture is controversial and regulation of its development unresolved. Our study provides an integral view of its architecture and critical information on the gene network controlling its development. Inflorescence architecture is a highly important trait depending on the arrangement and number of flowers in the inflorescence stem. It strongly contributes to plant morphological diversity, and since it determines the number of flowers and fruits, it has strong potential to influence crop yield. Soybean (Glycine max) is a highly relevant grain crop. However, despite many studies involving soybean inflorescence, no clear descriptions of its architecture are available, and the information on this question is controversial. In addition, though a model for the gene network controlling inflorescence meristem identity is established for other legumes, such as pea (Pisum sativum) or Medicago truncatula, regulation of soybean inflorescence development is not resolved, with the nature of the gene specifying I2 meristem identity not clear yet. Here, we use macroscopic and microscopic observation to analyze soybean inflorescence architecture and RNA in situ hybridization to study the expression of the meristem genes DT1, DT2 and GmAP1a, to analyze the control of soybean inflorescence development. Our data demonstrate that, as pea and Medicago, soybean has a compound inflorescence, with flowers formed in secondary inflorescences (I2), and suggest that it is a compound raceme. Our expression study supports that DT1 and AP1 specify the identity of I1 and floral meristems, respectively. Importantly, the specific expression of Dt2 in I2 meristems strongly indicates I2 meristem identity specification by Dt2 and conservation of the inflorescence gene regulatory network with other legumes. Our study fills an important gap, providing an integral view of soybean inflorescence architecture and novel critical information on the gene network that controls its development.

Main conclusion: Moderate concentrations of Na⁺ ions in the growth medium have positive effects on growth and performance characteristics of the C₄ euhalophyte Suaeda altissima, optimizing functioning of both, stomata and photosynthetic apparatus. Effects of salinity on the morphology, ion relations, and gas exchange of the leaves in the euhalophyte Suaeda altissima (L.) Pall. were investigated with emphasis on the guard and epidermal cells. The presence of NaCl in the nutrient solution (NS) at both growth-stimulating (250 mM) and growth-inhibiting (750 mM) concentrations resulted in increased leaf succulence, net photosynthetic rate (P_n), and instantaneous water use efficiency (WUE_i), and reduced stomatal conductance (g_s), stomatal density on the leaf surface, and transpiration rate (E). X-ray microanalyses revealed Na and Cl accumulation in the guard and epidermal cells of leaves under salinity conditions. However, Na and Cl contents differed by not much in plants grown at 250 and 750 mM NaCl, indicating a mechanism preventing accumulation of Na⁺ and Cl^- ions in cells paving leaf surface at high NaCl concentrations. Examination of g_s and E as functions of CO₂ concentration in the leaf gas exchange chamber revealed better ability to regulate these parameters in 250 mM NaCl-grown plants than in 750 mM NaCl-grown or control plants. The study of P_n dependent on CO₂ concentration in leaf intercellular space revealed direct stimulating effect of NaCl on photosynthesis. We hypothesize that S. altissima, a species having anatomy and ultrastructure features of C₄ plants, improves its performance characteristics under saline conditions, optimizing not only the functioning of the stomata complex but also the process of CO₂ assimilation, including the C₄ fixation pathway.

Main conclusion: Moderate drought stimulates phenolic biosynthesis in Polygonum equisetiforme, while severe stress restricts metabolite accumulation and triggers anatomical adaptations, including tissue thickness and xylem vessel density, supporting drought tolerance strategies. Water scarcity is a major environmental factor shaping plant growth, metabolism, and survival. In this study, the response of Polygonum equisetiforme to different irrigation regimes (100, 60, 30, and 15% of field capacity) was investigated with a focus on phenolic metabolism and anatomical traits. Total phenolics were quantified using spectrophotometric and chromatographic analyses, and the profiles of individual phenolic acids and flavonoids were examined by liquid chromatography-mass spectrometry. Drought stress promoted a general increase in total phenolic content, with maximum accumulation under moderate water deficit. Several phenolic acids, including gallic, protocatechuic, and caffeic acids, together with flavonoids such as catechin, epicatechin, and rutin, were most abundant at moderate stress but declined under severe limitation. In contrast, compounds such as p-coumaric and trans-cinnamic acids decreased progressively with increasing stress. Anatomical observations revealed clear modifications in leaves, stems, and roots. Leaf and mesophyll thickness, stem and pith diameters, and root cortex were reduced, whereas epidermal thickening and xylem vessel density increased, particularly under severe stress. These findings indicate that P. equisetiforme deploys complementary biochemical and anatomical adjustments to withstand drought. This work advances current knowledge by demonstrating that drought tolerance in P. equisetiforme arises from the combined reinforcement of secondary metabolism and structural traits, offering new perspectives for understanding adaptive mechanisms in stress-resilient plants.

Main conclusion: Partial male sterile mutant offers high hybrid recovery and seed set upon crossing. Partial sterility is recessive, monogenic and caused due to impairment of pollen function, which is supported by ddRAD sequencing. Finger millet, a nutri-cereal, has wider adaptability mainly grown as a rainfed crop in arid and semiarid tropics of Asia and Africa. Highly autogamous nature and small florets makes the hybridization tedious and hence the genetic improvement has been very slow. To address this, a novel partial male sterile mutant (ps1) was characterized extensively in line of its utility in hybridization breeding. An in vivo pollen study using fluorescence microscopy revealed the cause of partial male sterility in ps1 mutant as impairment of pollen germination and pollen tube growth on stigma. The mutant sets ~ 10% seeds upon bagging, 20% under open pollination and up to 49% in controlled crossing. Hybrid recovery (outcrossing) in 46 crosses with ps1 ranged from 28.6% to 81.2% with an average of 56.7% under controlled crossing. An extensive genetic study using 46 F₁, 46 F₂ and 1 F₃ population revealed monogenic and recessive nature of partial male sterility. To identify single nucleotide polymorphism (SNP) associated with partial male sterility, double-digested restriction site-associated DNA (ddRAD) sequencing of ps1 mutant and its wild type (GPU 28) was performed using Illumina Hi-Seq2000 and shortlisted 69 clusters were functionally annotated in UniProt database. The Cluster 53,954 has annotated MYB-like transcription factor (A0MLT6_ORYSJ) which plays vital role in pollen tube growth, which warrants further validation. Characterization of ps1 mutant in this study demonstrates simplified hybridization in finger millet. This would enable breeders to handle more crosses and frequent hybridization to achieve higher productivity.

Main conclusion: A comparative analysis of NaCl-stressed flax genotypes reveals that microRNA828a, microRNA399g, microRNA168a, catalase, shoot length, and shoot dry weight are the most influential salt stress-responsive variables irrespective of the lignan (secoisolariciresinol diglucoside) content declared for the genotypes. Lignans are powerful antioxidants and plant defence molecules whose roles in mitigating salt stress are rarely studied or understood, particularly in flax (Linum usitatissimum L.). Flax is a rich source of lignans. This study assessed the response to salt stress in two flax genotypes, Flanders and Astella. Astella has a higher content of the lignan secoisolariciresinol diglucoside (SDG) than Flanders. The 3-week-old flax plants were subjected to 100 mM NaCl salt stress for 1 week. Morphological analyses revealed that the growth of Flanders was more suppressed under stress, indicating resource-saving behaviour compared to Astella. Salt stress caused Astella to produce more reactive oxygen species (ROS) and incur more cell damage than Flanders. Flanders exhibited comparatively higher levels of antioxidants, osmoprotection machinery, and lignan-related microRNAs, suggesting its enhanced ROS scavenging and superior cellular protection capabilities than Astella. However, multivariate analysis could not provide evidence for the direct involvement of lignans in stress adaptation. Instead, it was hypothesised that microRNAs play a pleiotropic role in the adaptation to salinity. The results demonstrated Flanders' superiority to Astella in salt stress mitigation. The findings could be used to improve the salinity tolerance of flax and other crop plants in future research.