Plant signaling & behavior最新文献

Hardy kiwifruit (Actinidia arguta) is a climacteric fruit, a characteristic contributing to its short shelf life. Plant phytohormones such as salicylic acid (SA) are well known for their role in regulating the postharvest fruit ripening processes. Here, we investigated, for the first time, the effect of SA pretreatment on postharvest responses in the hardy kiwifruit cultivar 'Autumn Sense' during cold storage. SA pretreatment effectively maintained fruit firmness and titratable acidity during the first two weeks of storage, whereas both parameters declined sharply in untreated control fruits. Moreover, no ethylene production was detected in SA-pretreated fruits during the same period, likely due to modulation of gene expression in the ethylene biosynthetic pathway. These results suggest that SA pretreatment suppresses the early phases of ripening, thereby delaying fruit softening in hardy kiwifruit during cold storage. In addition, antioxidant activity and ascorbic acid content were significantly upregulated in fruits treated with 0.1 mM SA during the first week, indicating enhanced antioxidant accumulation. Overall, these findings provide valuable insights into the postharvest physiology of hardy kiwifruit and support the use of SA pretreatment as a strategy to extend shelf life and improve fruit quality in commercial storage and distribution.

Soil contamination with salinity and heavy metals such as cadmium (Cd) is becoming a serious global problem due to the rapid development of the social economy. Although plant growth-promoting rhizobacteria PGPR and organic agents such as salicylic acid (SA) are considered major protectants to alleviate abiotic stresses, the study of these bacteria and organic acids to ameliorate the toxic effects of salinity and Cd remains limited. Therefore, the present study was conducted to investigate the individual and combined effects of PGPR and SA on enhancing the phytoremediation of salinity (100 mM NaCl) and Cd (50 µM CdCl₂) using rice (Oryza sativa L.) plants. The research results indicated that elevated levels of salinity and Cd stress in soil significantly (P < 0.05) decreased plant growth and biomass, photosynthetic pigments, and gas exchange attributes. However, salinity and Cd stress also induced oxidative stress in the plants by increasing malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) by 44% and 38%, respectively, which also induced increased compounds of various enzymatic and nonenzymatic antioxidants, and also the gene expression and sugar content. Furthermore, a significant (P < 0.05) increase in cadmium accumulation, potential health risk indices, proline metabolism, the AsA-GSH cycle, and the pigmentation of cellular components was observed. Although the application of PGPR and SA showed a significant (P < 0.05) increase in plant growth and biomass, gas exchange characteristics, microbial diversity, functional gene abundance in the rhizosphere, enzymatic and nonenzymatic compounds, and their gene expression, and also decreased oxidative stress. In addition, the application of PGPR and SA enhanced cellular fractionation and decreased metal accumulation by 37% in shoots, proline metabolism, and the AsA-GSH cycle in O. sativa plants. These results provide new insights for sustainable agricultural practices and hold immense promise in addressing the pressing challenges of salinity and heavy metal contamination in agricultural soils.

Plant memory is an adaptive mechanism that plants can use to increase their fitness and cope with adverse environmental stresses. In this study, mRNA-sequencing (mRNA-seq), whole-genome bisulfite sequencing (WGBS) and real-time quantitative PCR (RT-qPCR) methods were applied for evaluating formation and maintenance of somatic transcriptional memory after treatment with ultrasound and drought stimuli in tomatoes. In addition, the effects of repeated stimuli, as well as the association-forming ability of plants were studied when they were trained previously with combined stimuli. Two days after exposure to the two stimuli applied alone or in combination, significantly altered gene transcription and DNA methylation were revealed. Using four selected target genes, we demonstrated that plants memorized stimuli for 5-10 d, in a gene- and stimulus-dependent way. The repeated application of the stimuli caused various alterations in gene transcription behavior, such as habituation, sustained induction or modified reinduction. Plants were able to use one conditioned stimulus as a predictor of the other, unconditioned one, after conditioning in the case of 3 out of 4 target genes, and used their transcriptional memory associatively. The exploitation of plant memory and associative learning may contribute to the development of new strategies to increase plant stress resilience.

The inhibition of primary root (PR) growth is a major developmental response of Arabidopsis (Arabidopsis thaliana) to phosphate (Pi) deficiency. Previously, our laboratory demonstrated that under Pi deficiency, a blue light-triggered malate-mediated photo-Fenton reaction and a canonical Fenton reaction in root apoplasts together form an Fe redox cycle, which results in Pi deficiency-induced inhibition of PR growth by continuously producing hydroxyl radicals (·OH). In this model, blue light, malate, Fe²⁺, Fe³⁺, H₂O₂, low pH, and low Pi are critical components, and the LPR1/LPR2 and STOP1-ALMT1 modules are key regulators that affect the occurrence and extent of these chemical reactions. However, whether the function of ALMT1 in the Pi deficiency-induced inhibition of PR growth relies on low pH in the rhizosphere and, conversely, whether ALMT1 is involved in regulating rhizosphere acidification remain elusive. Here, we show that low pH in the rhizosphere is required for malate-mediated inhibition of PR growth under Pi deficiency. Moreover, although not the principal factor, ALMT1 facilitates rhizosphere acidification under Pi deficiency. Our results shed new light on the function of ALMT1 and rhizosphere acidification under Pi deficiency.

Vascular tissues transport water and nutrients in plants, with the phloem distributing photosynthates from source to sink. The direction of phloem transport is determined by the positional relationship between sources and sinks and by vascular connections. Although aspects of phloem transport have been studied, a comprehensive understanding remains lacking. Here, we used soybean as a model system to investigate the translocation pathways and destinations of photosynthates using autoradiography with ¹⁴C-labeled sucrose and fluorescent imaging with carboxyfluorescein (CF), a known phloem tracer. Soybean exhibits simple phyllotaxy, with alternate trifoliate leaves arranged oppositely along the stem. Applying ¹⁴C-sucrose to mature leaves revealed that young developing leaves received photosynthates from source leaves on both sides of the stem. To visualize pathways, ¹⁴C-sucrose and carboxyfluorescein diacetate (CFDA) were applied to sequential source leaves. Signals from ¹⁴C and CF in the stem's vascular bundles showed no overlap, indicating distinct transport pathways. Additionally, when ¹⁴C-sucrose was applied separately to the left and right halves of a single mature leaf, it was followed corresponding sides to the sink leaves. These findings demonstrate that photosynthates are delivered to sink tissues via multiple, well-compartmentalized phloem pathways, providing new insight into the spatial organization of phloem transport.

Nonexpressor of pathogenesis-related genes 1 (NPR1) is a master regulator of salicylic acid (SA)- facilitated plant hormone signaling and plays a crucial role in plant defense through the activation of systemic acquired resistance (SAR). Although NPR1-like genes are associated with stress responses in a variety of plant species, no thorough genome-wide investigation of these genes has been undertaken in pearl millet (Pennisetum glaucum). This study discovered seven PgNPR1-like genes on four pearl millet chromosomes (Chr1, Chr2, Chr4, and Chr6), which exhibit close affinity to NPRs from other plants and have common gene structures, conserved motifs, and domains. The promoter regions of PgNPR1-like genes have numerous cis-acting elements connected with biotic and abiotic stresses, natural plant growth, and development. The qPCR results showed that PgNPR1-like genes were differentially expressed in distinct tissues, developmental stages, and under various biotic and abiotic stresses. Some putative NPR1-like genes, such as Pgl_GLEAN_10029279, Pgl_GLEAN_10004488, Pgl_GLEAN_10004489, and Pgl_GLEAN_10015079, showed considerable expression in response to abiotic stimuli such as heat, drought, and salinity. The PgNPR1-like gene Pgl_GLEAN_10029279 was observed to be differently expressed upon treatment of hormones such as SA and MeJA. Pgl_GLEAN_10029279 was also significantly expressed after Magnaporthe grisea infection, which causes blast in pearl millet. In silico expression study of the PgNPR1-like genes after Sclerospora graminicola infection, causing downy-mildew disease, revealed that Pgl_GLEAN_10029279 and Pgl_GLEAN_10004489 were significantly upregulated. In addition, the docking results also showed that Pgl_GLEAN_10029279 and Pgl_GLEAN_10007810 out of all seven PgNPRs have strong interactions with the ligand SA, which proves their potential involvement in SA signaling and hence plant defense. These results offer a firm framework for comprehending the roles and development of PgNPR1-like genes in pearl millet.

Reynoutria japonica, a perennial herb of the Polygonaceae family, is a traditional Chinese medicinal plant known for its diverse pharmacological activities and broad applications in medicine, agriculture, and related fields. This review explores the functions and regulatory mechanisms of its secondary metabolites by summarizing their types, bioactivities, and biosynthetic regulation. Additionally, it examines how factors such as plant age, medicinal organ, soil composition, and cultivation conditions influence the secondary metabolite profile. These insights support the clinical application and industrial development of R. japonica.

Seeds, which are imperative for the propagation of seed plants, are also of major nutritional and economic value in agriculture. The precise dormancy and germination of crop seeds are important traits for modern agriculture. Pre-harvest sprouting (PHS) or the germination of seeds while attached to the plant before harvest, is a significant problem in crops, particularly in cereals. Therefore, understanding the various mechanisms of seed development and dormancy are imperative. While the molecular and hormonal aspects of seed dormancy are well understood, the role of epigenetic pathways is just beginning to unravel, particularly for cereal crops. The majority of this information has been generated in Arabidopsis; however, there is increasing focus on cereal crops such as rice and maize. Other important cereal crops, such as wheat and barley, lag behind even though seed dormancy and PHS are even more critical for these crops. Similarly, while much progress has been made in understanding the role of histone modifications in seed development, the role of DNA methylation has not been well investigated. In this article, we review the progress made in uncovering the role of epigenetic modifications in cereal crops with reference to knowledge generated in Arabidopsis.

Class III peroxidases (PRXs) are plant-specific enzymes that play vital roles in various physiological processes. However, the functional roles of mango PRXs under stress conditions remain poorly understood. In this study, we identified 76 MiPRX genes, which are unevenly distributed across the mango chromosomes. RT-qPCR analysis revealed differential expression of most MiPRX genes under oxidative, drought, and salt stress conditions, with MiPRX27 showing a particularly prominent role. Under oxidative stress, heterologous overexpression of MiPRX27 in Arabidopsis enhanced lateral root formation and accelerated root growth, suggesting that MiPRX27 contributes to reducing plant sensitivity to oxidative stress. Overall, this study provides a theoretical foundation for further exploration of MiPRX-mediated mechanisms underlying mango stress tolerance.

Glycyrrhiza is a perennial leguminous plant with salt tolerance, and its roots and rhizomes possess extremely significant medicinal value. The proper salinity can facilitate the growth of Glycyrrhiza and increase its content of medicinal ingredients. However, excessive salinity can negatively affect growth and medicinal component contents. The salt tolerance mechanism has not yet been fully elucidated, especially the information of chloroplast genome is in short supply. Present research investigated the genetic diversity of Glycyrrhiza by conducting comparative genomic, adaptive evolutionary, haplotype, population structure, and phylogenetic analyses of the chloroplast genes. Transcriptome analysis revealed that the chloroplast genes of different Glycyrrhiza varieties respond to salt stress at different stages and that these responsive genes are associated predominantly with the photosynthetic structure and regulation of protein synthesis. The editing efficiency of the psbA and rrn23 genes increases significantly under salt stress, potentially contributing to plant adaptation. In summary, analysis of the chloroplast genome provided valuable insights into the genetic diversity and phylogenetic relationships of Glycyrrhiza. Furthermore, transcriptomic data supplemented existing knowledge on chloroplast-mediated salt tolerance mechanisms, offering a foundation for future investigations into the adaptive strategies of Glycyrrhiza under saline conditions.