Plant breeding, aimed at enhancing desired traits, depends on genetic diversity. Mutation breeding is a powerful method of rapidly expanding genetic diversity, facilitating crop improvement, and ...ensuring food security. In a recent study, researchers evaluated the genetic variability of
species using different doses of sodium azide (SA) (0.2%, 0.4%, 0.6%, 0.8%, and 1.0%) through morphological, physiological, and cytogenetic studies. Morphological variations were observed in cotyledonary leaves, vegetative leaves, and overall plant growth and habit. Several quantitative parameters, such as plant height, fertile branches per plant, pods per plant (or clusters), seeds per pod, and seed yield, increased when treated with 0.2% and 0.4% SA compared to the control. Furthermore, the total chlorophyll content and carotenoids increased in the sample treated with 0.2% SA over the control but decreased with higher concentrations. Scanning electron microscopy revealed that stomatal aperture and seed dimensions increased at lower concentrations of sodium azide treatment. The study found a positive correlation between the different parameters studied in the
species, as indicated by high r-values. Based on their findings, it was concluded that the genotype of fenugreek can be improved by using 0.2% and 0.4% concentrations of sodium azide. However, the evaluation of observed variants in successive generations is a critical and necessary process to validate their potential as keystones for crop genetic improvements.
Ug99 (TTKSK) and Digalu (TKTTF) race groups of Puccinia graminis f. sp. tritici (Pgt), are thought to be the most virulent, rendering many wheat stem rust resistance genes (Sr) ineffective. A total ...of 600 single pustule Pgt isolates were collected from eight Egyptian provinces during 2016–2022, undergoing both phenotyping and genotyping assays. Among these, 129 viable samples (v-samples) underwent phenotyping using the North American differentials delineated to Pgt races in the TTKS (Ug99) and TKTTF race groups, identifying 24 distinct physiologic races of Pgt. Notably, seven virulent races, TKTTF (Digalu), TKKTF, TKPTF, TKKTP, TTRTF, TTTTF, and TKFTF, were discovered in Egypt. The host reaction of wheat germplasm to these seven races indicated a high level of susceptibility. A set of 437 dead samples (d-samples) of Pgt isolates from Egypt were genotyped using newly created 17 core SNP markers. Genotypic analysis revealed that these seven races could be classified into two major clades: III and IV. Within these clades, six subclades were identified, namely III-B, IV-A.2, IV-B, IV-E.1, IV-E.2, and IV-F. These SNP genotypes exhibited a broad geographic distribution, highlighting the global movement of Pgt populations across Europe, Asia, and Africa. Notably, none of these genetic groups were present in Egypt before 2016. The most prevalent genotypes were subclades IV-A.2 (TKTTF; Digalu), IV-E.2 (TKKTF, TKPTF, TKFTF), and III-B (TTRTF). The prevalence of these unique genotypes/races suggests clonal reproduction and evolution within them. Race TKKTP (subclade IV-E.1) is particularly concerning because of its ability to overcome the resistance conferred by gene Sr24 against race TTKSK (Ug99). Phylogenetic analysis of Pgt genetic groups revealed that the majority of identified races belong to TKTTF (Digalu) race group (subclade IV-A.2). Notably, no races were found to belong to the TTKS (Ug99) race group (clade I). This information should help breeders select a broader range of resistance genes that are both diverse and effective to enhance the durability of stem rust resistance.
•Race phenotyping resulted in identification of 24 races of Puccinia graminis f. sp. tritici (pgt).•Seven Pgt races revealed a broad distribution, virulence and diverse range.•Genotyping using a new custom SNP assay divided Pgt races into two major clades, III and IV.•Genotyping/races belonged to Digalu race (subclade IV-A.2), but not to Ug99 race (clade I).
Osmotic imbalance is one of the major consequences of drought stress, negatively affecting plant growth and productivity. Acetic acid has modulatory roles in osmotic balance in plants; however, the ...mechanistic insights into acetic acid-mediated osmotic adjustment under drought stress remains largely unknown.
Here, we investigated how seed priming and seedling root treatment with acetic acid enabled maize plants overcoming polyethylene glycol (PEG)-induced drought effects.
Maize seeds primed with acetic acid showed better growth performance when compared with unprimed seeds under PEG application. This growth performance was mainly attributed to improved growth traits, such as fresh weight, dry weight, length of shoots and roots, and several leaf spectral indices, including normalized difference vegetation index (NDVI) and chlorophyll absorption in reflectance index (MCARI). The levels of oxidative stress indicators hydrogen peroxide (H
O
) and malondialdehyde (MDA) did not alter significantly among the treatments, but proline content as well as the expression of proline biosynthetic gene,
(
) was significantly elevated in plants receiving acetic acid under PEG-treatments. On the other hand, treating the seedlings root with acetic acid led to a significant recovery of maize plants from drought-induced wilting. Although growth traits remained unchanged among the treatments, the enhancement of leaf water content, photosynthetic rate, proline level, expression of
, and antioxidant enzyme activities along with reduced level of H
O
and MDA in acetic acid-supplemented drought plants indicated a positive regulatory role of acetic acid in maize tolerance to drought. Moreover, the high expression of
and the subsequent elevation of proline level upon acetic acid application were further validated using wild type and proline biosynthetic mutant
of Arabidopsis. Results showed that acetic acid application enabled wild type plants to maintain better phenotypic appearance and recovery from drought stress than
plants, suggesting a crosstalk between acetic acid and proline metabolism in plants under drought stress.
Our results highlight the molecular and intrinsic mechanisms of acetic acid conferring plant tolerance to drought stress.
Wheat is an important cereal crop constrained by several biotic and abiotic stresses including drought stress. Understating the effect of drought stress and the genetic basis of stress tolerance is ...important to develop drought resilient, high-yielding wheat cultivars. In this study, we investigated the effects of drought stress on seedling characteristics in an association panel consisting of 198 germplasm lines. Our findings revealed that drought stress had a detrimental effect on all the seedling characteristics under investigation with a maximum effect on shoot length (50.94% reduction) and the minimum effect on germination percentage (7.9% reduction). To gain a deeper understanding, we conducted a genome-wide association analysis using 12,511 single nucleotide polymorphisms (SNPs), which led to the identification of 39 marker-trait associations (MTAs). Of these 39 MTAs, 13 were particularly noteworthy as they accounted for >10% of the phenotypic variance with a LOD score >5. These high-confidence MTAs were further utilized to extract 216 candidate gene (CGs) models within 1 Mb regions. Gene annotation and functional characterization identified 83 CGs with functional relevance to drought stress. These genes encoded the WD40 repeat domain, Myb/SANT-like domain, WSD1-like domain, BTB/POZ domain, Protein kinase domain, Cytochrome P450, Leucine-rich repeat domain superfamily, BURP domain, Calmodulin-binding protein60, Ubiquitin-like domain, etc. Findings from this study hold significant promise for wheat breeders as they provide direct assistance in selecting lines harboring favorable alleles for improved drought stress tolerance. Additionally, the identified SNPs and CGs will enable marker-assisted selection of potential genomic regions associated with enhanced drought stress tolerance in wheat.
Although trace elements are essential for life, environmental contamination due to metal accumulation and overuse in various sectors, such as healthcare, agriculture, industry, and cosmetics, poses ...significant health concerns. Exposure of plants to heavy metals leads to the overproduction of reactive oxygen species (ROS) due to their ability to change mitochondrial membrane permeability and restrict the action of ROS clearance enzymes in the cellular antioxidant system. The interaction of ROS with cellular membranes, heavy-metal-induced interactions directly or indirectly with different macromolecules, and signaling pathways leads to the accumulation of environmental pollutants and oxidative stress in exposed organisms. The heavy metal–ROS–cell signaling axis affects various pathological processes such as ATP depletion, excess ROS production, mitochondrial respiratory chain damage, decoupling of oxidative phosphorylation, and mitochondrial death. This review focuses on discussing the toxic effects of different heavy metals on plants, with particular emphasis on oxidative stress, its consequences, and mitigation strategies.
Trigonella foenum graecum
L. (Fenugreek) is a valuable medicinal plant cultivated for decades for its therapeutic characteristics. Still no pronounced improvement concerning wild form was ...accomplished as it is a self-pollinating crop. Induced mutagenesis is encouraged as a remarkable tool on this plant to circumvent the genetic bottleneck of cultivated germplasms. As a result, novel allelomorphic combinations for short-term agronomic attributes were developed. Fenugreek cultivar Pusa Early Bunching, selected for the present experiment, was mutagenized with five doses (0.2%, 0.4%, 0.6%, 0.8%, and 1.0%) of caffeine and sodium azide (SA) to evaluate its impact on the qualitative and quantitative traits of M
1
and M
2
generation conducted in a Complete Randomized Block Design (CRBD), replicated five times during 2019–2020 and 2020–2021, respectively. The frequency of induced phenotypic variations was assessed in M
2
progenies, resulting in the identification and isolation of a broad spectrum of mutants with altered phenotypes. Mutagenic effectiveness and efficiency were found to be maximum at lower concentrations of the mutagen treatments and highest in SA, followed by caffeine. Various morphological mutants with modified characters were observed at different concentrations in M
2
generation. The spectrum of mutations was wider in SA than in caffeine, as caffeine produced 51 while SA produced 54 individual mutants under seven major categories. The maximum frequency of morphological mutants was associated with leaf, followed by plant size, plant growth habit, pod, seed size, seed shape, and seed color. Morphological and structural variations in the guard cells of stomata and seeds were observed through scanning electron microscopy. The variations created in the economically important traits may enrich the genetic diversity of this plant species. Moreover, these morphological mutants may serve as a source of elite genes in further breeding programs of fenugreek.
The genetic diversity and the relationships among sesame cultivars were investigated using physiological and cyto/molecular analysis. To our information, no studies have yet been conducted on the ...genetic evaluation of sesame genotypes based on cyto/molecular analysis in Saudi Arabia. This study showed that genotype Bah-312 had the highest values from physiological and biochemical traits (plant height, harvest index, total plant dry matter, seed yield, oil content, and fatty acids content). Using 20 ISSR and 25 SCoT primers, the studied genotypes amplified 233 and 275 alleles, while the average polymorphism percentage (P%) was 65.32% (ISSR) and 77.8% (SCoT) across all the studied genotypes, respectively. To assess the markers efficiency analysis the polymorphism information contents (PIC), Marker Index (MI), Effective Multiplex Ratio (EMR), Resolving Power (Rp) were estimated. In general, primers (ISSR 2 & SCoT 21) and (ISSR 4 & SCoT 3) revealed the highest and lowest values for P %, PIC, MI, and EMR%. Furthermore, 188 positive and negative unique bands were detected, out of which ISSR generated 84, while 104 were amplified by SCoT analysis. In this regard, genotype Bah-312 generated 41 unique amplicons, and Jiz-511 genotype 23 unique amplicons. In the same context, the population genetics parameters, number of different alleles (Na), number of effective alleles (Ne), Shannon’s index (I), expected heterozygosity (He), and Unbiased Expected Heterozygosity (uHe), were calculated. ISSR marker showed the highest values for all the estimated parameters. In this regard, genotype Bah-312 exhibited the highest values (1.35, 1.37, 0.31, 0.21, 0.29) & (1.31, 1.35, 0.30, 0.20, 0.27) while, genotype Ahs-670 revealed the least values (1.29, 1.31, 0.26, 0.16, 0.23) &(1.14, 1.26, 0.22, 0.15, 0.20) for ISSR and SCoT markers respectively. For cytological data, according to the highest asymmetry index (AsK%) and lowest total form percentage (TF%) values, genotype Ahs-670 was the most advanced cultivar, and genotype Bah-312 was the most primitive one. According to the degree of asymmetry of karyotype (A) and intrachromosomal asymmetry index (A1), sesame genotype Ahs-670 was the most asymmetrical, and Bah-312 was the most symmetrical genotype. This study gives some helpful information about the genetic diversity of six sesame landraces. The variation harbored by these landraces could be used in sesame breeding programs.
Water deficit is one of the most significant abiotic factors affecting rice and agricultural production worldwide. In hybrid rice, cytoplasmic male sterility (CMS) is an important technique for ...creating high-yielding crop based on heterosis. The phytohormone kinetin (Kin) regulates cell division in plant during the early stages of grain formation, as well as flow assimilation and osmotic regulation under water stress. The present study performed to estimate the effects of irrigation intervals (irrigation each six days (I.sub.6), nine days (I.sub.9), twelve days (I.sub.12) and fifteen days (I.sub.15) against continuous flooding (CF, each three days)) and kinetin exogenously application (control, 15 mg L.sup.-1 and 30 mg L.sup.-1) on hybrid rice (L1, IR69625A; L2, G46A and R, Giza 178 R) seed production. Leaves traits (Chlorophyll content (CHC), relative water content (RWC), stomatal conductance (SC), Leaf temperature (LT) and transpiration rate (TR)), floral traits such as style length (SL) and total stigma length (TSL), in addition to root traits (i.e., root length (RL), root volume (RV), root: shoot ratio (RSR), root thickness (RT), root xylem vessels number (RXVN) and root xylem vessel area (RXVA) were evaluated and a significant enhancement in most traits was observed. Applying 30 mg L.sup.-1 kinetin significantly and positively enhanced all growth, floral and roots traits (RV and RXVA recorded the most increased values by 14.8% and 23.9%, respectively) under prolonging irrigation intervals, in comparison to non-treated plants. Subsequently, spraying kinetin exogenously on foliar could be an alternative method to reduce the harmful influences of water deficiency during seed production in hybrid rice.
Plants possess various defense mechanisms to cope with genotoxic and environmental challenges, with high temperatures posing a significant threat due to global warming. In this investigation, ...ten-day-old Trigonella foenum-graecum (fenugreek) seedlings were cultivated in a controlled environment chamber with conditions set at 70–80% relative humidity, a day/night cycle of 25/18 °C, and a photosynthetically active radiation (PAR) of 1000 μmol m−2 s−1. Other groups of seedlings were subjected to temperatures of 30, 35, or 40 °C. Our research aimed to investigate the relationship between temperature intensity, duration, growth responses, physiological and metabolic activities, and the stress alleviation by salicylic acid. The results demonstrated that high temperatures significantly reduced plant growth, membrane stability, while increasing proline and protein content, as well as electrolyte leakage in the leaves. The most pronounced results were observed when exposed to 40 °C for 24 h. Salicylic acid completely mitigated the negative impacts of high-temperature stress when it was applied at 40 °C for 24 h. We utilized two-dimensional electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry to examine proteins across three groups: control plants, stressed plants, and plants subjected to salicylic acid treatment. Our results revealed that, among the proteins influenced by high-temperature stress, 12 displayed the most significant differences in regulation. These stress-responsive proteins played roles in signal transduction, stress defense, detoxification, amino acid metabolism, protein metabolism (including translation, processing, and degradation), photosynthesis, carbohydrate metabolism, and energy pathways. These proteins may hold practical implications for diverse biological activities. In conclusion, salicylic acid treatment enhanced thermotolerance in fenugreek plants, although further investigation is required at the genome level to elucidate the mechanism of salicylic acid action under heat stress.
