Journal of Plant Molecular Breeding
Volume:12 Issue: 2, Summer and Autumn 2024

Ginkgo biloba is the oldest living plant on Earth and one of the most widely used natural medicines worldwide. Flavonoids extracted from G. biloba have been shown to have protective effects against cardiovascular and cerebrovascular diseases. The bHLH transcription factors (TFs) are among the most important families of transcription factors in plants, playing a crucial role in regulating plant growth, development, and secondary metabolism. In this study, GbbHLH13 was isolated and identified. It encodes a protein consisting of 732 amino acids, and transient expression assays in tobacco indicated that GbbHLH13 is localized in the nucleus. Exogenous hormone treatments revealed that the expression of GbbHLH13 is affected by methyl jasmonate (MeJA) and abscisic acid (ABA). Transient overexpression experiments further showed that it upregulates the transcription levels of flavonoid metabolism-related genes PAL, CHI, and C4H, suggesting that GbbHLH13 may be involved in flavonoid biosynthesis.

Transposable  genetic elements (TEs) are dynamic DNA sequences that significantly impact plant gene expression, enabling adaptation to environmental stresses. This review explores the role of TEs in plant adaptation, focusing on the mechanisms of TE activation and suppression, including chromatin remodeling, DNA modifications, and small interfering RNAs (siRNAs). Stress conditions trigger TE activation through interactions between stress-induced transcription factors and TE promoters, as seen with retrotransposon families like COPIA93 and ONSEN in  modulation of stress-responsive genes. Understanding these mechanisms provides valuable insights for agriculture, particularly in developing crops that are resilient to climate change. Leveraging TE-mediated gene regulation presents innovative strategies for enhancing plant adaptation, highlighting the potential of TEs in genetic manipulation for plant improvement.

Phytohormones, also known a plant growth regulators, regulate various physiological processes in plants, including germination, growth, and response to biotic and abiotic stresses. Plant diseases, caused by pathogens such as fungi, bacteria, and viruses, often alter hormonal pathways, leading to the simultaneous induction of antagonistic and synergistic hormones in plants. In resistant varieties, however, the hormonal responses follow a more sequential pattern. Plant hormone signaling pathways are primarily polarized along two antagonistic axes: the salicylic acid (SA) and jasmonic acid (JA) pathways on one side, and the ethylene pathway on the other. In addition to SA, JA, and ethylene, other growth regulators, such as auxins, brassinosteroids, cytokinins, and abscisic acid (ABA), also play significant roles in plant responses to biotic stress and are increasingly recognized for their importance in plant-pathogen interactions.  Pathogens can modulate hormone biosynthesis and signaling to suppress plant defenses and alter the cellular environment, promoting their infection and proliferation. In this article, we will review the latest advances in understanding the function and regulation of plant hormones, the modulation of plant defense responses, and their synergistic and the crosstalk between phytohormones and defense pathways.

Assessment of the genetic diversity of germplasm is essential for sound germplasm management and its successful utilization in breeding programs. This study aimed to estimate genetic diversity among plantain accessions and establish relationships among the genotypes using simple sequence repeat (SSR) markers. SSR markers amplified 21 alleles, 3.50 alleles per locus, and major allele frequency (mean ± SD, 0.80 ± 0.34) across the 20 plantain accessions. The polymorphic information content (PIC) and Shannon's diversity index ranged from 0.054 to 0.919 and 0.000 to 1.864, respectively. Analysis of molecular variance (AMOVA) showed that 88% genetic variation occurred among genotypes within populations, with minimal variation observed between populations. This resulted in Nei genetic distance and FST values being negligible when distinguishing the populations. The gene flow rate unequivocally demonstrated the efficacy of employing co-dominant markers, as evidenced by both the Principal Coordinates Analysis (PCoA) and the dendrogram. This study revealed a clear-cut genetic variation among the 20 plantain accessions across plantain populations and established new cluster groups, providing valuable insights for future use in breeding programs.

In terminal drought conditions, the limitations on current photosynthesis can improve the influence of cereal stem carbohydrate reserves on preserving grain yield. This study investigated how the remobilization of stem fructans affects barley yield under drought conditions. The present study performed comparative physiological and gene expression analyses using flag leaf, penultimate, and peduncle tissues from four barley genotypes (G1, G2, G3, and G4). We examined the expression levels of fructan metabolism genes in drought-stressed leaf, stem penultimate, and peduncle tissues during the grain-filling stage, comparing them to those under normal conditions. Notably, genetic variability among the cultivars influences the expression of drought-responsive genes associated with tolerance. Specifically, genotypes 1 and 3 showed an up-regulation of fructan metabolism genes in response to drought, while genotypes 2 and 4 exhibited a down-regulation. Our findings indicated that increased fructan accumulation and its subsequent remobilization significantly contribute to the yield stability of G1 and G3 under drought stress conditions. Barley genotypes that demonstrate a strong capacity for fructan production and remobilization in response to terminal drought stress could serve as valuable resources for breeding programs aimed at improving drought tolerance through the selection of these traits.

In this study, the response of 17 durum wheat genotypes to cadmium stress was assessed using an aeroponic growth system at the seedling stage. The following parameters were evaluated: glutathione peroxidase (GPX), root dry weight (RDW), malondialdehyde (MDA), cadmium of root (CR), leaf dry weight (LDW), catalase (CAT), cadmium of leaf (CL), ascorbate peroxidase (APX), chlorophyll (Chl) based on SPAD index, seedling dry weight (SDW), electrical conductivity (EC), and glutathione S-transferase (GST). Biplot analysis revealed that the first two principal components explained 64% of the observed variabilities. The pentagon plot highlighted that genotype G15 under cadmium stress exhibited the highest values for GST, GPX, MDA, and CAT; while under non-cadmium stress, it showed high APX activity and superior RDW, LDW, Chl, SDW, and EC values. G2 under cadmium stress was notable for its high CR and CL levels. Regarding seedling dry weight performance, G2 and G15 under non-cadmium stress, followed by G14 and G16, demonstrated the highest results. APX emerged as the most discriminative trait, followed by GST, GPX, CAT, and EC, as determined by the treatment-by-trait biplot. Under cadmium-stress , genotypes G6, G8, G9, G11, and G12 were identified as superior for seedling dry weight.

Kunitz (KTI) and Bowman-Birk (BBI) protease inhibitors are considered the most significant factors that decrease the quality of soybean proteins. In this study, the levels of these proteins were investigated using the 2D-PAGE, and their activity was evaluated through trypsin and chymotrypsin proteases in ten Iranian soybean cultivars. These results indicated that the Katol cultivar has the lowest concentration of both KTI and BBI proteins and the lowest trypsin and chymotrypsin inhibitory levels.  Therefore, this cultivar is an ideal choice for soybean protein-based diets and could also serve as a valuable parent in breeding programs aimed at improving protein quality in soybean . Moreover, no significant correlation was found between KTI with BBI proteins, nor between these proteins with protease activity. Therefore, it seems that genetic control targeting either KTI or BBI proteins alone may not be an effective approach to improving the quality of soybean proteins. Additionally, no correlation was found between KTI and BBI proteins with agronomic traits. This also suggests that reducing protease inhibitors in soybean proteins does not adversely affect overall soybean performance.

Brassinosteroids (BRs) play  crucial role in growth and development of plants. The BRI1 receptor is the main receptor for BR hormones, which is a member of the leucine-rich kinase-like receptors. The BRI1 receptor has been reported in multiple plant species, but structural differences between monocots and dicots remain poorly understood. In the present study, bioinformatic analyses of the BRI gene sequence were conducted on dicot and monocot plants with existing genomic data. The analysis of genome data from 95 plants species revealed a presence of 141 BRI1 genes, with 92 being dicot and 49 being monocot. Different evolutionary paths have been identified for BRI1 genes in monocots and dicots through analysis of the phylogenetic tree. Additionally, our analysis of BRI1 orthologs based on physicochemical properties indicated a conserved structure among BRI1 proteins, with distinctions noticeable between monocots and dicots. The majority of BRI1 genes were found to contain a single exon and the average MW and pI values for BRI1 were lower in monocots compared to dicots. However, we predicted a greater number of phosphorylation sites in BRI1 orthologs of monocots. This study offers insights for future research on BRI1 genetic modification.

Medicinal plants improve human health, strengthen the immune system, reduce inflammation, and facilitate the treatment of diseases. To investigate the effect of drought stress (after 10 and 20 days of water withdrawal, representing mild and severe drought stress, respectively) and melatonin and salicylic acid on the biochemical and morphological indicators of the Acorus calamus medicinal plant, an experiment was conducted. Results showed that using melatonin and salicylic acid increased the activity of peroxidase enzyme under drought conditions. Also, salicylic acid increased the activity of catalase enzyme in mild drought stress. The application of melatonin and salicylic acid under severe drought stress increased the activity of the catalase enzyme.  Under drought stress conditions, the use of salicylic acid and melatonin led to an increase in plant dry weight compared to normal conditions. Also using melatonin under severe drought conditions resulted in an increase in dry weight in comparison with the control treatment. In conclusion, while the plant's responses to stress and elicitors differed across various characteristics, it can generally be stated that salicylic acid and melatonin positively influence the biochemical and morphological traits of Acorus calamus under severe and mild drought stress conditions.

Isoflavones are natural phytoestrogens and belong to a subgroup of flavonoids that can be found mainly in legume plants, especially soybeans (Glycine max L.) and the other plants of the Fabaceae family. They have a structure similar to 17β-estradiol, which allows them to bind estrogen receptors and exhibit estrogenic or antiestrogenic effects. They are found in non-fermented products mainly as glycosides. During the fermentation process, they are converted into bioactive aglycones. Isoflavones are also linked to antioxidant and therapeutic benefits, supporting bone health and cholesterol regulation. Soybean-derived isoflavones, especially genistein, show strong anticancer potential by inhibiting cell growth. Epidemiological studies indicate, that consumption of isoflavones may reduce the risk of some diseases, including breast cancer but these compounds' clinical application is limited due to poor bioavailability, solubility, and stability. Today, integrating traditional medicine and medicinal plants with modern medicine could offer new opportunities for treating various diseases. Nanocarriers such as liposomes, dendrimers, and nanoparticles have been developed to enhance the bioavailability and controlled release of soy isoflavones, enabling their targeted delivery to cancer cells while minimizing off-target effects. In this review, we examine how nanotechnology synergizes with Glycine max-derived isoflavones to enhance their bioavailability and biological activity, considering the challenges and limitations of this approach for therapeutic development.

Medicinal and aromatic plants have long played a vital role in health, wellness, and culinary practices. This research aimed to assess the genetic variation in essential oil content and its components among five local landraces of dill (Anethum graveolens L.) from Mashhad, Ardabil, Parsabad, Bushehr, and Esfahan. Essential oil and its composition, including β-pinene, α-terpinene, β-phellandrene, carvacrol, dillapiole, neophytadiene, and hexahydrofarnesyl acetone, were analyzed. The drawn biplot explained 90% of the variation, clearly depicting genotype-trait relationships. It revealed both additive and crossover interactions, suggesting that genotype rankings were trait-dependent. Among the evaluated genotypes, Bushehr exhibited the highest essential oil yield and quality, followed by Esfahan, Mashhad, Ardabil, and Parsabad. The strongest positive correlations were observed between β-phellandrene, dillapiole, and essential oil content, while the association between α-terpinene and β-pinene was more intricate and less pronounced. The superior performance of the Bushehr genotype makes it a prime candidate for future breeding initiatives. Furthermore, carvacrol emerged as the most discriminative trait for disticnting among genotype.  The study also revealed that increased in essential oil content in A. graveolens was associated with higher production of dillapiole and β-phellandrene, coupled with reduced levels of β-pinene, neophytadiene, and hexahydrofarnesyl acetone.

Salinity stress is one of the most significant factors limiting plant growth; therefore, using compounds such as methanol to mitigate the harmful effects of stress is of great importance. This study aimed to investigate the effect of methanol spraying on the physiological and biochemical characteristics of coriander (Coriandrum sativum) plants under salinity stress conditions in a greenhouse experiment. Salinity treatment was applied at two levels (control and 80 mM NaCl) and methanol  was exogenously applied at four concentrations (control, 10%, 20%, and 30%). The results indicated that under salinity stress conditions, the application of methanol led to a significant increase in various traits.  Superoxide dismutase enzyme activity increased by 23% with 30% methanol spraying under salinity stress. Additionally, polyphenol oxidase enzyme activity rose by 51% with 30% methanol at 80 mM salinity, while  catalase activity increased by 29%. Proline content also increased by 124% under salinity stress, while  malondialdehyde content decreased by 63% in these conditions.  Overall, 30% methanol enhances stress tolerance in plants under salinity conditions by improving antioxidant enzyme activities, protein content, and osmoprotective mechanisms. These findings suggest the role of methanol's in mitigating the effects of salinity stress on plant physiology.