Current Plant Biology最新文献

Rorippa sylvestris (L.) Besser. (yellow fieldcress) is a hyperaccumulator of cadmium (Cd) discovered recently. There are several studies in the topic of Cd tolerance capacity and detoxification mechanism of plants, but the detoxification mechanism of R. sylvestris is not clear. Root tiller seedlings of R. sylvestris were planted in the brown bottles filled with culture solution containing different levels of Cd (0, 10, 25, 50, 100, 200 μmol·L⁻¹, respectively) for 8 days in order to make sure the physiological responses, Cd subcellular distribution and chemical forms under Cd stress. The results showed that the growth increased in lower Cd concentration and declined in higher Cd concentration. Physiological characteristics such as photosynthesis and MDA were not significantly affected compared with the control at Cd concentratetion ≤ 50 μmol·L⁻¹. The content of soluble sugar and free proline increased with the increasing of Cd concentration for the purpose of reducing the Cd toxicity to plant. R. sylvestris had a strong capability of Cd accumulation in different Cd treatments. The concentration of Cd in plant tissues (root, stem, leaf) was in the order of root>stem>leaf. The Cd subcellular distribution in plant tissues of R. sylvestris was in the order of soluble fractions>cell wall>protoplast>mitochondria. Cd was mainly extracted by deionized water and 80% ethanol (60.91–69.76%), followed by sodium chloride (16.14–25.12%), which indicated that R. sylvestris achieved to enhance Cd tolerance capacity and detoxification mechanism through root retention and vacuolar compartmentalization.

The Heat Shock Transcription Factor (Hsf) serves as a critical transcription factor in plants, exerting its function by binding to specific promoter regions in response to heat stress. This activation leads to the up-regulation of heat shock proteins. Taraxacum kok-saghyz Rodin (TKS) is a plant species that produces high quality natural rubber in its root latex. During the growth of TKS, various stresses can affect its defense mechanisms and overall growth. However, studies investigating the Hsf transcription factors in TKS remain limited. In this study, we identified and named 31 Hsf transcription factors in TKS and performed a comparative analysis of their core motifs and gene structures. Based on phylogenetic analysis, these transcription factors were classified into three distinct classes. By cis-element analysis of the TKS promoter genes, we gained valuable insights into the evolutionary characteristics of the TKS Hsf gene family. Transcriptome expression profiling data revealed different expression of various genes within the same tissues. Several TKS Hsf genes exhibited responsiveness to various abiotic stresses and hormonal treatments, indicating their involvement in regulating the plant's response to different environmental conditions. Overall, the Hsf gene family in TKS plays a critical role in plant growth, development, and adaptation to abiotic stresses. This study provides a basis for further functional validation of TKS Hsf genes and elucidation of the regulatory mechanisms of target genes.

The increase in root hair length and density is considered an effective way to deal with external phosphorous (P) limitation. The identification of useful loci for root hair traits is crucial for wheat breeding. Here, We employed a simple, cost-effective, and medium-throughput screening method using cigar rolls to assess P-responsive root hair length (RHL) and density (RHD) in bread wheat at the seedling stage. A set of 113 historical bread wheat cultivars was screened for root hair length and density (RHL/D) under low (0.005 mM KH₂PO₄) and high P-levels (0.25 mM KH₂PO₄). Significant variations (p < 0.001) were found among genotypes for length and density under both P treatments. Genotyping was performed using 50 K SNP array data to conduct the genome-wide association study (GWAS) using a multi-locus model (mrMLM) and 67 SNPs linked to RHL/D under phosphorous treatment were identified. Of these, 33 SNPs were associated with RHL and 34 were linked with RHD. The maximum number of SNPs (43) linked to target traits were observed under high-P levels following 24 were identified under low-P conditions. We also identified 6 SNPs associated with target traits causing missense mutations and predicted their candidate genes of which 5 were protein coding. RNA-seq based expression analysis indicated that all genes were expressed in roots of 24 wheat varieties ranging from 0.38 to 101.7 tpm. The least expression (0.41–10.28 tpm) was observed in TraesCS4D02G066200 which consisted of non-translating CDS and was highly expressed in leaf tissues with 14.55–53.67 tpm. Of these genes, TraesCS1A02G313600 solely expressed in roots with no expression (0 tpm) in leaf tissues. This first GWAS study on root hairs in bread wheat illustrates the genetic basis of RHL and RHD and identifies loci that could be an invaluable resource for further functional investigation.

Milk thistle (Silybum marianum L. Gaertn.) is an important herbaceous and annual plant that is used as a pharmaceutical for the remedy and prevention of liver diseases. Till now, there have been no reports of miRNAs’ involvement in the production of secondary metabolites in milk thistle. The present study was conducted with the aim of investigating the foliar application of chitosan and titanium dioxide (bulk and nano forms) on seed silybin content and the crosstalk of miRNAs and target genes. The ideal formulation [bulk and nanoparticles (NPs)] and concentration (0–100 mg L⁻¹) of titanium dioxide and chitosan applications for upregulating seed silybin content were investigated across five ecotypes. Additionally, the expression of miRNAs and their target genes involved in silybin biosynthesis were evaluated. Data revealed that foliar application of elicitors increased the content of silybin A, silybin B, and total silybin in all five ecotypes. The cultivar 'Budakalazi' had the best response compared to other ecotypes. The application of chitosan and TiO₂ decreased the expression of all five miRNAs in the phenological stage of immature seeds. In contrast, target gene expression was generally upregulated. miRNAs expression was generally linked to the phenological stage of mature seed, as miR156b, miR1438, and miR157a-5p were over-expressed, while miRNAs miR1873 and miR829.1 were down-regulated. In general, foliar application of Nano chitosan, especially at a concentration of 50 mg L⁻¹, increased the amount of silybin content by reducing the expression of most miRNAs, and upregulating the transcription of their target genes involved in silybin biosynthesis.

The age of trees and palms is fundamental with respect to their probability of survival, the quality and quantity of their production and their value as unique specimens. Determining these ages is necessary in different contexts (natural, forest, agriculture, urban trees and landscaping). Dendrochronology makes it possible to determine the age of trees, but for palms (Arecaceae) it is still lacking. Here we present and use a method based on the study of whole palm tree images and linear regression of stem/crown ratio and age in years, created with individuals of known age, and posterior probability distribution functions using Bayesian and Monte Carlo methods. This methodology is applicable to the estimate of adult palm individuals of different Arecaceae genera that reach the maximum dimensions of crown once became adult, provided an ensemble of individuals with known age is available for comparison. This approach is here applied to the estimation of the age of Canary Islands palm trees. The proposed methodology shows that the age in years of a Canary Islands palm tree is 28.33 × stipe (S)/crown (C) ratio + 7.03 ± s. The application of the methodology allowed the discovery of a dispersal event around 1840–1845, unknown until now, and revealed two palms from Tenoya (Gran Canaria, Spain) as the oldest known living Canary Islands palms, with an estimated age of over three hundred years.

Trees in urban forests are able to better air quality by removing particulate matter (PM) from the atmosphere through the accumulation of particles on their leaf surfaces. When exposed to air pollutants, the physiology, morphology, and biochemistry of a plant may be affected, which will result in alterations to that plant’s function and growth. In this study, we assessed, for the first time, the tolerance or sensitivity of four evergreen trees (Ficus benghalensis, Ficus religiosa, Mangifera indica, and Polyalthia longifolia) towards air pollution by employing several indices. The trees, which are commonly grown along the roadside in Dhaka, Bangladesh, were evaluated by using the air pollution tolerance index (APTI), the anticipated performance index (API), and the metal accumulation index (MAI). The deposition of four heavy metals (Cd, Cr, Pb, and Ni) on the leaves of four aforementioned tree species was studied employing ICP-MS, and subsequently, a predictive foliar MAI was created. APTI values of the studied plants varied from 10.31 to 12.51 implying that they were either intermediately tolerant or sensitive. A significantly strong positive correlation was obtained between APTI and relative water content (RWC) (r = 0.864; p < 0.001) and between APTI and ascorbic acid content (AAC) (r = 0.748; p < 0.01). The API revealed M. indica as a good performer, which maintained the highest score (68.75%) among the tree species irrespective of different sites. The Pb concentrations were anomalously high in the atmosphere of Dhaka, suggesting its anthropogenic origin. A significant (r = 0.722; p < 0.01) relationship was found between Cd and Pb indicating their common origin. Among the species, F. benghalensis had the highest MAI value (13.60). The MAI value was found to have a significant association with pH, AAC, and total chlorophyll content. Based on APTI, API, and MAI values, the most suitable plant species for urban forest development was identified to be M. indica followed by F. benghalensis and F. religiosa.

Pepper (Capsicum spp.) holds significant value as both a vegetable and a spice crop cultivated across the world, belonging to the genus Capsicum of the Solanaceae family. In addition to its culinary and spice applications, pepper finds extensive utility in the pharmaceutical and cosmetics sectors. Breeding pepper plants with improved nutritional qualities will require a comprehensive understanding of biosynthetic pathway genes and their regulatory functions. Advances in molecular biology and biotechnology have facilitated the identification of genes involved in carotenoid, anthocyanin, and capsaicinoid biosynthesis, providing opportunities for the development of new pepper cultivars with tailored levels of desired metabolites. Further advances in high-throughput sequencing methods and computational analyses will allow more efficient and accurate identification and functional characterization of genes and regulatory elements participating in biosynthesis and regulation of these traits. This review discusses the present understanding and avenues for further investigation into the genetic and molecular control of carotenoid, anthocyanin, and capsaicinoid biosynthetic pathways in pepper.

Hydroxypyruvate (HP), the key intermediate of photorespiration, is converted to glycerate via the catalysis of hydroxypyruvate reductases (HPRs) with NADH/NADPH as cofactors. The non-lethal phenotype resulting from HPR defects allows for the use of mutants to investigate interactions between photorespiration and other cellular processes, facilitating the establishment of plant chassis with compromised photorespiration. Considering that establishing a plant chassis of the HPR- series would provide great potential in promoting plant synthetic biology to tackle future challenges, the genome-wide identification and bioinformatics analysis of HPR gene family in N. benthamiana are imperative but remains to be solved. In this study, 12 N. benthamiana hydroxypyruvate reductases (NbHPRs) were identified from a genome-wide study. These genes could be classified into three subclasses by phylogenetic analysis, and conserved gene structures or motif compositions were identified in each subclass. A variety of signal-sensing elements were identified in the HPRs promoter regions indicating their regulation by multiple potential transcription factors such as C2H2 proteins. Quantitative real-time PCR (qRTPCR) results further demonstrated the higher expression levels of NbHPRs in functional and young leaves compared to other organs. Subsequently, we confirmed the subcellular localization of NbHPRs with transient expression analysis, which suggests their different functions. Moreover, the relative expression level of the gene under nitrogen (N) treatment was assessed through qRTPCR analysis. These works will offer valuable insights into elucidating the function and mechanism of HPRs in N. benthamiana, thus illuminating the strategies for introducing artificial carbon fixation pathways to tackle future challenges with the modification on photorespiration.

A plant-growth promoting bacterial consortium of halotolerant Bacillus sp. and Pseudomonas sp. was evaluated for the ability to prime banana (Musa acuminata cv. Berangan) plants against abiotic (salinity) and biotic (Foc-TR4) stress challenges. PGPB consortium-primed banana plants showed better growth (plant height, root length and root biomass) and improved physiological parameters (relative water content, chlorophyll, and carotenoid contents) in both stressed conditions compared to non-primed banana plants. In addition, primed banana plants showed a reduction in lipid peroxidation and an increase in proline and antioxidant enzymatic activities (superoxide dismutase, catalase, ascorbate peroxidase, peroxidase, and glutathione reductase). In salt-stress conditions (sea salt at 100 mM NaCl equivalent), primed plants showed higher levels of K⁺, Ca²⁺, and Mg²⁺ and lower levels of Cl^- and Na⁺ compared to non-primed salt-stressed plants. Under Foc-TR4 stress, the primed plants showed significant enhancement in the levels of total soluble phenolics, lignin content and defense-related enzyme activities (β-1, 3-glucanase, phenylalanine ammonia lyase, chitinase, polyphenol oxidase, and lipoxygenase). Expression analysis of nine stress-responsive MaWRKY genes (MaWRKY4, MaWRKY23, MaWRKY24, MaWRKY25, MaWRKY28, MaWRKY45, MaWRKY65, MaWRKY89 and MaWRKY145) showed significant upregulation in primed banana plants under salt and Foc-TR4 stresses compared to non-primed plants. These results demonstrate that inoculation with the PGPB consortium improved banana plant growth characteristics and primed WRKY-mediated protection against abiotic and biotic stresses.