Current Plant Biology最新文献

Members of bZIP gene family play crucial roles in various biological processes, including plant growth and development, stress response, and light signal transduction. Despite their significance, there is limited information on the function of the bZIP gene family in peanuts. In this investigation, we identified a total of 99 bZIP gene family members in the peanut genome, distributed across 20 chromosomes. Phylogenetic tree analysis categorized the peanut bZIP gene family into 10 groups, with groups I, D, A and S being the most widely distributed. Transcriptome analysis of peanut pods revealed that 10 bZIP family genes exhibited significant induction in response to light, suggesting their potential involvement in light signal transduction in peanuts. Within the peanut bZIP family, group H comprises six genes AhbZIP13, AhbZIP63, AhbZIP39, AhbZIP44, AhbZIP91 and AhbZIP96. Particularly, the expression of the AhbZIP63 (AhHYH) gene significantly increased under light induction, indicating a pivotal role in light signal transduction. DAP-seq analysis of AhbZIP63 (AhHYH) demonstrated its direct regulation of genes associated with UV response and cellular response to nutrient levels.

Iron is an essential plant nutrient, and a continuous supply of it is required as it is a key factor in various metabolic processes, including photosynthesis, chlorophyll synthesis, and respiration. Various transcription factors are known to regulate iron homeostasis in plants, and the bHLH transcription factor family is one of them. The StbHLH47 is a homologue of the Arabidopsis POPEYE (PYE), which is known to repress iron homeostasis-related genes in Arabidopsis. Potato is the most consumed vegetable in the world and is low in iron content. We have generated CRISPR/Cas9-edited StbHLH47 lines and performed a detailed analysis of these lines. The analysis revealed that the roots of StbHLH47 edited lines have decreased ferric chelate reductase (FCR) activity compared to the roots of the wild-type (WT) plant. We also observed that CRISPR/Cas9 edited lines have fewer trichomes when compared to the WT plant. The expression of genes associated with iron homeostasis was also measured. Compared to the control, the expression of StbHLH47 was downregulated in the edited lines, while the expression of StNAS4, StOPT3, and StFRO3 was upregulated. This suggests the negative regulation of StbHLH47 in modulating iron. The iron content was also quantified using inductively coupled plasma mass spectrometry (ICP-MS) and found to be increased in the generated transgenic lines when compared to WT plants. Overall, this study reveals that StbHLH47 negatively regulates the expression of iron homeostasis-related genes. StbHLH47 edited lines exhibited decreased FCR activity, changes in phenotype, and increased iron content in the potato plants.

Key message

This study provides novel insight into the role of StbHLH47 in modulating iron content in Solanum tuberosum and controlling the expression of various iron homeostasis-related genes.

Sakuranetin, a flavonoid phytoalexin in rice, plays a crucial role in defense against pathogen infection. While MYB-type transcription factors are well-known to regulate plant growth, development, secondary metabolism, and adaptation to environmental stresses, the function of rice MYB-related transcription factors in sakuranetin biosynthesis and sakuranetin-mediated defense remains unclear. In this study, we identified and characterized OsMYB1R, a novel single repeat MYB transcription factor that acts as a transcriptional activator in sakuranetin biosynthesis. Protein-DNA binding and activation assays revealed that OsMYB1R directly regulates the gene promoter of OsNOMT, a key enzyme in sakuranetin synthesis. Molecular analyses and infection studies using OsMYB1R-overexpressing (OsMYB1R-OE) and OsMYB1R-knockout (Osmyb1r, generated using CRISPR/Cas9) plants demonstrated that OsMYB1R increases sakuranetin production and decreases Magnaporthe oryzae infection by transcriptionally regulating OsNOMT expression. This finding indicates a positive regulation of sakuranetin biosynthesis and antifungal resistance by the OsMYB1R-OsNOMT crosstalk. Interestingly, the alteration of OsMYB1R expression did not affect yield-related agronomic traits. Our results reveal a novel and positive role of 1R-MYB in secondary metabolite biosynthesis and pathogen defense, suggesting that OsMYB1R is a potential gene for effectively enhancing rice resistance without compromising yield.

The NAC (NAM, ATAF and CUC) family is one of the largest transcription factor (TF) families in plant that are involved in the regulatory mechanisms of plant growth and development as well as responses to abiotic stresses. However, the underlying molecular mechanism of drought-responsive NAC family members in soybean still remains inexplicit. In this study, a total of 179 GmNAC genes were identified in the soybean genome. We discovered that the majority of GmNAC members have more than three exons and share a gene and motif structure that is mostly conserved at the N-terminus. Phylogenetic analysis suggested that soybean GmNAC proteins were divided into 10 separate groups. The analysis of cis-elements highlighted the potential role of GmNAC genes in various hormonal and defense related activities. In addition, most of the GmNAC genes showed notable expression in roots and leaves, suggesting their likely role in abiotic stress adaptation. The overexpression of GmNAC3-OE in Arabidopsis increased tolerance to drought stress. Similarly, the GmNAC3-OE plants displayed better survival rates, root length and antioxidant activities. Enhanced expression of stress specific genes in GmNAC3-OE was also recorded. Our findings revealed the potential role of GmNAC3 gene role in regulating soybean response to drought stress and could be used as a potential marker to generate stress resilient plants.

Salinity stress is considered as one of the major detrimental stresses for reducing plant growth and crop productivity. Hence, concerted efforts are going on to develop sustainable solutions for reducing salinity-induced negative effects on crop productivity. Given this, the present study evaluated the potential of ash gourd extract (AGE; 0.9 µg/mL) for ameliorating NaCl (100 mM) stress in rice, which is one of the major staple food crops worldwide. The differential phenotyping revealed growth reduction under NaCl treatment, as indicated by 0.27- and 0.36-fold decrease in survival and whole-seedling biomass, respectively, compared with those of control. In contrast, 24 h pre-treatment with AGE before NaCl exposure (AGE24h+NaCl) improved these growth attributes by 1.29- and 1.70-fold, respectively, compared with those of NaCl treatment. The differential phenotype of AGE was associated with its inherent ability to scavenge reactive oxygen species, which was equivalent to 0.08-fold of ascorbic acid. The higher accumulation of superoxide radicals and upregulated expression of stress marker genes including OsTSPO, OsCBS, OsHKT1;5, and OsNHX1 under AGE24h treatment also suggested AGE mediated priming effect. Under AGE24h+NaCl, the expression levels of these stress markers were either maintained or their extent of upregulation was further enhanced. In addition, the coordinated activation of antioxidant machinery and reduced Na-accumulation further supported stress amelioration under AGE24h+NaCl treatment. GC-MS-based metabolomics highlighted fatty acids, malic acid, myo-inositol, allose, trehalose, and L-oxoproline, as key metabolites, associated with AGE-mediated amelioration of NaCl stress. The foliar application of AGE increased seed yield and 1000 seed weight by 1.13- and 1.06-fold, respectively, compared with those of NaCl, validating its agronomic feasibility. Thus, the results highlighted the application of AGE, as a “green” bioregulator for ameliorating NaCl stress conditions in rice.

The biotrophic fungus Hemileia vastatrix is the pathogen responsible for coffee leaf rust, a devastating disease in several coffee-producing countries. Despite the importance of studying the interaction between Coffea and H. vastatrix, a more comprehensive understanding of the mechanisms involved in this pathosystem is necessary. The role of eight candidate genes was analyzed aiming at identifying and validating new important coffee resistance genes and understanding their interaction with H. vastatrix. These genes were identified in the most important sources of coffee resistance, the Híbrido de Timor CIFC 832/2 and CIFC 832/1. Previous works found six resistance genes and, in our research, other two new genes were identified in BAC clones and validated by RT-qPCR during compatible and incompatible interactions between Coffea and H. vastatrix. An interactome approach was performed using Coffea-H. vastatrix and Coffea-Coffea proteins to better understand the biological process and the interaction of the host-pathogen. Two networks of interactions from the compiled data were built focused on candidate genes associated with pre-haustorial resistance (12 and 24 h.a.i) in coffee plants against the pathogen. The results showed, for the first time, differentially expressed proteins (DEPs) positively regulated in the incompatible interaction Coffea-H. vastatrix. These coffee proteins interact with each other and with secreted and/or transmembrane pathogen proteins. The obtained results also show that DEPs found are involved in important plant defense pathways such as pathways associated with the response to wounds, signaling, regulation of the innate immune response and the transmembrane receptor protein serine/threonine kinase pathway. The present work shows the involvement of genes in both pathogen recognition and signaling cascades, which act in pre-haustorial defense mechanisms of HdT coffee. Therefore, the candidate genes analyzed, together with the biological processes elucidated, have the potential to contribute to the development of new control strategies against the fungus H. vastatrix within coffee breeding programs aiming to develop cultivars with durable resistance.

Pollen analysis is essential for discerning the botanical and geographical origins of honey, ensuring authenticity, quality, and commercial value. The Sahara Desert in Algeria boasts unique floral diversity, with its melliferous plant species contributing to regional honey production. Nevertheless, a lack of comprehensive information on the pollen characteristics of these plants impedes precise identification of the geographical and botanical origins of Saharan honeys. Given the importance of understanding honey origin for quality assurance, this study addresses the challenge posed by the scarcity of melissopalynological data in the Sahara Desert. By offering a detailed characterization of Sahara Desert melliferous plant pollen, the research contributes valuable insights to the broader field of honey authentication and underscores its significance in the industry. Therefore, this study was conducted to characterize the pollen of melliferous plants in the Sahara Desert, which is essential for establishing a database that can aid in the determination of honey origins, protect against fraudulent activities, and support conservation efforts. This study aimed at the characterization of pollen of spontaneous melliferous plants from the Sahara Desert of Algeria to facilitate the determination of the geographical and botanical origin of honeys produced in this region. In three regions (Ghardaïa, Touggourt and Ouargla), pollen morphological features namely: polar length (PL) and equatorial diameter (ED), size, shape, apertures and exine ornamentations of 19 native plant species were studied through the sampling of ten flowers per plant and ten pollen grains per flower for each species (n = 3800 measurements). The surveyed plant species showed that medium-sized pollens (25–50 µm) were the most dominant (73.34 %), followed by slam-sized pollens (21.18 %), with the smallest size observed in Tetraena alba (PL = 18.98 ± 4.82 μm, ED = 18.95 ± 5.06 μm) and the largest size measured in Faidherbia albida (PL = 58.03 ± 4.65 µm, ED = 57.46 ± 4.70 μm). The most frequent forms of pollen in different species were prolate-spheroidal (32.68 %) and oblate-spheroidal (26.53 %). Diverse types of exine ornamentations and were detected at the pollen unit level with a dominance of reticulate (57.89 %). Tricolporate (42.11 %) and tricolpate (31.58 %) were the dominate pollen apertures. This study characterized pollen from Sahara Desert melliferous plants, which can aid honey origin determination, ensuring quality and supporting conservation, with implications in authentication, protection, and preservation of floral resources for sustained honey production.

The plant cell wall, a vital component in providing structural integrity and facilitating growth, comprises cellulose microfibrils among its major constituents. This study employed Atomic Force Microscopy (AFM) to investigate the intricate relationship between genetic mutation, cellulose microfibril organization, nanomechanical properties of cellulose microfibrils and plant growth. Focusing on the Arabidopsis thaliana wild type (WT) and ixr1–2 mutant population (known for resistance to herbicide ISOXABEN), we utilized AFM to scrutinize cellulose microfibrils on the newly synthesized cell wall in 5-day-old dark-grown hypocotyls. Our macroscopic analysis revealed significant differences in plant growth, prompting a detailed examination at the nanoscale using AFM to discover if the macroscopic disparity between these two populations gets translated in structural details, orientation, and mechanical properties of cellulose microfibrils at the nanoscale too. AFM analysis highlighted distinct organizational disparities in cellulose microfibrils between the WT and mutant population. Our results revealed that the WT manifests a more aligned and oriented microfibril structure in contrast to the mutant population that shows significantly less aligned cellulose microfibrils in the plant growth direction. Also, the WT and mutant population demonstrate nuanced differences in height, width, roughness, deformation, and stiffness. The observed nanoscale alterations in microfibril structure and nano-mechanical properties contribute to an improved understanding of the intricate dynamics governing plant cell wall structure and its pivotal role in growth and development.

Heterotrimeric GTP-binding proteins or G-proteins are pivotal players in the intricate signaling cascades of plant cells, operating through their binding to guanine nucleotides. These G-proteins primarily consist of three essential subunits: Gα, Gβ, and Gγ. Among these subunits, Gγ stands out for its remarkable genetic diversity. In the present investigation, six Gγ subunits were identified in the Indian variety T-163 of the pea plant (Pisum sativum). Notably, two of these novel Gγ subunits, named PsGγ1 and PsGγ2, belong to type A, while PsGγ3 falls within the type B category. The remaining three subunits, namely PsGγ4, PsGγ5, and PsGγ6, are classified under type C. An in-depth comparison of the amino acid sequences of these pea Gγ subunits with their counterparts in other plants, including Arabidopsis thaliana and Oryza sativa, has unveiled significant variations. This research explores the impact of different treatments on PsGγ genes (PsGγ1 to PsGγ6) in plants. Noteworthy discoveries include a 4-fold increase in the expression of PsGγ1, PsGγ4, PsGγ5, and PsGγ6 in the presence of nitrogen. PsGγ2 and PsGγ3, however, show no response. Phosphorus induces a 3-fold upregulation in PsGγ2 and PsGγ4, and a 4-fold increase in PsGγ5. Conversely, the absence of phosphorus triggers a 4-fold upregulation in PsGγ4 and PsGγ5. Heat stress leads to a 3-fold upregulation in PsGγ2, PsGγ4, and PsGγ5, while cold stress results in a 3-fold upregulation of PsGγ1 and PsGγ6. Under high salt conditions, PsGγ1, PsGγ3, PsGγ4, and PsGγ6 exhibit a 4-fold upregulation, with PsGγ2 showing a 2-fold increase. PsGγ4 and PsGγ5 display a 4-fold upregulation in response to ABA, while PsGγ2 and PsGγ3 show a 3-fold increase while MeJA induces a 4-fold upregulation in PsGγ5. Notably, this study unveils, for the first time, the significant role of Gγ subunits during endosymbiotic associations with phosphorus-acquiring AMF with AMF triggering a 4-fold upregulation in PsGγ4 and PsGγ6. The presence of multiple Gγ subunits in pea underscores their critical participation in governing plant development, stress responses, nutrient sensing, and interactions with mycorrhizal fungi.