Search Results (67)

Conventional plant breeding relies on the occurrence of chromosomal crossover and spontaneous or non-targeted mutations in the genome induced by physical or chemical stressors. However, constraints exist concerning the number and variation of genotypes that can be achieved in this way, as the occurrence and combination of mutations are not equally distributed across the genome. The underlying mechanisms and causes of reproductive constraints can be considered the result of evolution to maintain the genomic stability of a species while at the same time allowing necessary adaptations. A continuous horizon scan was carried out to identify plants derived from new genomic techniques (NGTs), which show that CRISPR/Cas is able to circumvent at least some of these mechanisms and constraints. The reason for this is the specific mode of action: While physico-chemical mutagens such as radiation or chemicals merely cause a break in DNA, recombinant enzymatic mutagens (REMs), such as CRISPR/Cas, additionally interfere with cellular repair mechanisms. More recently developed REMs even expand the capabilities of NGTs to introduce new genetic variations within the target sequences. Thus, NGTs introduce genetic changes and combinations that are unknown in the current breeding pool and that are also unlikely to occur as a result of any previously used breeding methods. The resulting genotypes may need to be considered as ‘new to the environment’. The technical potential of NGTs should also be taken into account in regulatory provisions. Previously unknown genotypes and phenotypes may negatively impact plant health, ecosystems, biodiversity, and plant breeding. It must further be acknowledged that the different outcomes of NGTs and conventional breeding are not always evident at first sight. As a starting point, within a process-oriented approval process, molecular characterization can inform the following steps in risk assessment and guide requests for further data. Full article

Understanding the genetic architecture of complex traits is crucial for crop improvement and molecular breeding. We developed a mutagenized soybean population using carbon ion beam irradiation and conducted genome-wide association studies (GWAS) to identify variants controlling key agronomic traits. Whole-genome resequencing of 199 M4 lines revealed 1.48 million SNPs, predominantly C→T transitions, with population structure analysis identifying three distinct genetic groups. GWAS across five traits revealed striking differences in genetic architecture: the podding habit showed extreme polygenic control with 87,029 significant associations of small effect, while pubescence color exhibited oligogenic inheritance with only 122 variants. Hundred-seed weight displayed moderate complexity (4637 associations) with the largest effect sizes (−3.74 to 5.03) and major QTLs on chromosomes 4, 7, and 15–20. Growth habit involved 12,136 SNPs, including a strong chromosome 3 association (−log₁₀(p-value) > 50). Flower color showed 2662 associations clustered on chromosome 15. Functional analysis of 18,542 candidate genes revealed trait-specific pathway enrichments: flavonoid biosynthesis for flower color, phloem transport for seed weight, auxin signaling for growth habit, and amino acid transport for podding habit. This study demonstrates how mutagenesis-induced variation, combined with association mapping, reveals evolutionary constraints that shape genetic architectures, providing insights for genetics-assisted breeding strategies. Full article

Veronica nakaiana Ohwi and Veronica pusanensis Y.N.Lee are rare and endemic plants native to Korea, with increasing interest in their cultivation and breeding for industrial applications. Mutation breeding is important for developing horticultural cultivars. Among mutation breeding techniques, chemical mutagenesis is particularly accessible and effective. Colchicine-induced mutagenesis was performed in vivo at various concentrations (0.2%, 0.4%, 0.6%, 0.8%, and 1.0%) and treatment durations (1, 2, 3, 4, and 5 h). Both V. nakaiana Ohwi and V. pusanensis Y.N.Lee showed the highest survival (23.4% and 34.8%, respectively) and mutation (1.6% and 0.5%, respectively) rates with 0.2% colchicine. Flow cytometry and chromosome number analyses revealed mutants as tetraploid, with chromosome numbers ranging from 2n = 66 to 2n = 68. Stomatal analysis indicated increased stomatal length and width and decreased stomatal density. Morphological analysis of the mutants revealed that the leaves of V. nakaiana Ohwi and V. pusanensis Y.N.Lee were significantly larger and had different shapes compared to the control. This study successfully generated new mutant plants of two Veronica species using chemical mutagen treatment, which could be utilized as new genetic resources for various Veronica species breeding programs in the future. Full article

Colchicine, a strong antimitotic drug produced by the crocus Colchicum autumnale, induces polyploidy by interfering with spindle formation during mitosis, making it a crucial tool in plant breeding. In this review, we give a comprehensive overview of the function of colchicine in plant enhancement, emphasizing its modes of action, application techniques, and effects on phytochemistry, physiology, and plant morphology. A wide variety of plant species, especially medicinal plants, have been studied in this context, utilizing in vitro, ex vitro, and in vivo methods for applying colchicine. In addition, we discuss the safety and effectiveness of colchicine in comparison to other polyploidy-inducing drugs, including oryzalin, trifluralin, and mutagens such as ethyl methanesulfonate and methyl methanesulfonate. Furthermore, the effects of colchicine on genetic stability and secondary metabolite production are discussed, with a focus on its usefulness in boosting the medicinal and economic potential of the target species. This synthesis highlights the ongoing use of colchicine in plant breeding and provides useful information and suggestions for future advancements in crop development via induced polyploidy. Full article

Inefficient crop phosphorus (P) use impacts global food security and P fertilizer use can be environmentally harmful. Lines homozygous for barley (Hordeum vulgare L.) low phytic acid 1-1 (lpa 1-1) have yields equivalent to the wild type but ~15% less seed Total P (TP). The objective here was to identify second-site mutations in the lpa1-1 background that condition a further reduction in seed TP, again with little impact on yield. A chemically mutagenized population was derived from lpa 1-1 and screened to identify lines with seed TP reductions greater than 15% (as compared with wild-type) but with seed weights per plant within 80% of wild-type. Three M₄ lines were selected and evaluated in a greenhouse pot experiment. Plants were grown to maturity either on a soil with low soil P fertility (16 to 25 mg Olsen P L⁻¹; Soil P Index 1) or with that soil supplemented (36 kg P ha⁻¹) to provide optimal available soil P. Mean seed P reduction across the three lines and two soil P levels was 28%, a near doubling of the lpa1-1 seed Total P reduction. When grown with optimal soil available P, no impact of these putative mutations on grain yield was observed. These findings suggest that the three lpa 1-1-derived mutant lines carry second-site mutations conferring substantially (~17%) greater decreases in seed TP than that conferred by lpa 1-1. If the putative mutations are confirmed to be heritable and to have negligible impact on yield, they could be used in breeding P-efficient barley cultivars as a step towards reducing regional and global P demand. Full article

The utilization of aerospace mutagenesis in plant breeding is a novel, efficient technology. This study investigates the effects of aerospace mutagenesis on tea tree growth, soil nutrient conversion, and soil microbial community structure and function. The results showed that aerospace mutagenized tea trees showed increased leaf area, 100-bud weight, and yield. The rhizosphere soil of mutagenized tea tree displayed an increase in microorganisms, enhanced carbon and nitrogen cycling capacity, and significant increases in nutrient conversion and antioxidant enzyme activities. In addition, the content of available nutrients was also increased. Aerospace mutagenesis showed an increase in the abundance of soil-characteristic microorganisms (Solirubrobacterales bacterium, Capillimicrobium parvum, Mycobacterium colombiense, Mycobacterium rhizamassiliense, and Conexibacter woesei), and enhancement of the intensity of metabolic pathways, glyoxylate and dicarboxylate metabolism, biosynthesis of secondary metabolites, microbial metabolism in diverse environments, carbon metabolism, fatty acid metabolism, carbon metabolism, biosynthesis of amino acids, and biosynthesis of cofactors of soil microorganisms. Interaction network and partial least squares structural equation modeling (PLS-SEM) equation analysis showed that after aerospace mutagenesis, soil-characteristic microorganisms positively affected soil microbial functions, soil microbial biomass carbon and nitrogen, respiration intensity, and soil enzyme activities; furthermore, it improved available nutrient content and tea tree growth. This study provides an important reference for the cultivation and management of aerospace mutagenized tea trees and microbial regulation of tea tree growth. Full article

The role of onion as the second most-consumed and cultivated vegetable around the world and its renowned qualities that lead it to be called the “queen of the kitchen” have positioned it as a vital source of nutritional and economic contributions around the world. Polyploidy serves as a groundbreaking innovation in plant breeding, improving the yield and vigor of plants. This study was conducted to determine the effects of applying different concentrations of colchicine to onion seedlings on their morphology, antioxidant activity, and dissolved sugars. The mutagen was applied to the onion seeds at three different concentrations (0.05, 0.1, and 0.2% w/v) for an exposure period of 24 h. A chromosomal analysis confirmed the induction of polyploidy, which led to the successful duplication of the chromosome number from diploid (2n = 16) to tetraploid (4n = 32). The control recorded a survival rate of 91.57%, while 83.33%, 3.33%, and 0.00% survival rates were recorded for seedlings treated with 0.05%, 0.1%, and 0.2% (w/v) concentrations of colchicine, respectively. Furthermore, the tetraploids showed significant differences in morphology, producing the tallest seedlings (reaching up to 73.6 cm tall) and the greatest average bulb diameter (of 5.64 cm) after 14 weeks. The tetraploids also showed significant differences in antioxidant activity and the amount of dissolved sugars, recording the highest DPPH scavenging percentage of 72.58% and refractive index of 1.369. Successful induction of polyploidy was achieved with the application of 0.05% (w/v) colchicine, which produced tetraploids that are morphologically and biochemically superior to other treated and control plants at a significance level of p < 0.05. Full article

Background: Ethyl methyl sulfonate (EMS) mutagenesis is widely used because of its advantages of inducing point mutations and no need for genetic transformation. To identify germplasm resources of processed tomatoes with superior comprehensive traits suitable for cultivation in Xinjiang. Methods: In this study, tomato seeds were treated with 2% EMS reagent for 12 h, 21 quality traits and 20 quantitative traits of 33 processed tomatoes derived from EMS-mutagenized“M82”were evaluated. Results: The results indicated that for traits such as hypocotyl color, growth habit, plant type, leaf type, and leaf shape, the range of quantitative trait variation was 8.45–37.25%, with a genetic diversity index ranging from 1.25 to 2.07. Conclusions: Cluster analysis of quantitative traits categorized the 33 EMS-mutagenized “M82” processed tomato resources into five groups: Group I contained 22 robust germplasm samples; Group II consisted of a single potential high-quality germplasm; Group III comprised five germplasm with a small and extreme plant type; Group IV included four high-yield germplasm; and Group V represented one moderate, conventional germplasm. Raw data from 15 quantitative traits across the 33 accessions were standardized using the “extreme method” to extract six comprehensive factors. The top 10 germplasm resources based on the comprehensive score were 76, 137, 97, 102, 19, 104, 21, 108, 17, and 147. It provides some theoretical basis for realizing the high-yield and high-quality cultivation and variety breeding of processed tomatoes in Xinjiang. Full article

Most cultivated potato (Solanum tuberosum) varieties are highly susceptible to common scab (Streptomyces scabei). The disease is widespread in all major potato production areas and leads to high economic losses and food waste. Varietal resistance is seen as the most viable and sustainable long-term management strategy. However, resistant potato varieties are scarce, and their genetic architecture and resistance mechanisms are poorly understood. Moreover, diploid potato relatives to commercial potatoes remain to be fully explored. In the current study, a panel of 384 ethyl methane sulfonate (EMS)-mutagenized diploid potato clones were evaluated for common scab coverage, severity, and incidence traits under field conditions, and genome-wide association studies (GWASs) were conducted to dissect the genetic architecture of their traits. Using the GAPIT-MLM and RTM-GWAS statistical models, and Mann–Whitney non-parametric U-tests, we show that 58 QTNs/QTLs distributed on all 12 potato chromosomes were associated with common scab resistance, 52 of which had significant allelic effects on the three traits. In total, 38 of the 52 favorable QTNs/QTLs were found to be pleiotropic on at least two of the traits, while 14 were unique to a single trait and were found distributed over 3 chromosomes. The identified QTNs/QTLs showed low to high effects, highlighting the quantitative and multigenic inheritance of common scab resistance. The QTLs/QTNs associated with the three common scab traits were found to be co-located in genomic regions carrying 79 candidate genes playing roles in plant defense, cell wall component biosynthesis and modification, plant–pathogen interactions, and hormone signaling. A total of 61 potato clones were found to be tolerant or resistant to common scab. Taken together, the data show that the studied germplasm panel, the identified QTNs/QTLs, and the candidate genes are prime genetic resources for breeders and biologists in breeding and targeted gene editing. Full article

The cultivated peanut (Arachis hypogaea L.) is a main cash crop globally, providing oil, protein, and various beneficial phytochemicals, with high-oleic peanut offering enhanced health benefits and oxidative stability. Despite these advantages, many widely cultivated peanut varieties remain normal-oleic, and the conversion of these varieties to high-oleic types without compromising yield and adaptability is of significant interest. This study evaluated the feasibility of using Pingyangmycin, a chemical mutagen, to induce high-oleic mutations in the popular peanut variety 308 through floral organ injection. The results showed that this method effectively generated high-oleic mutants with oleic acid content exceeding 75%. The mutants yielded more pods and kernels than the parental variety. Genotypic analysis confirmed mutations in the FAD2A and FAD2B genes, associated with the high-oleic phenotype. This novel approach, which reduces seed and reagent requirements and accelerates the breeding timeline, holds promise for enhancing peanut breeding programs and the development of high-oleic cultivars with superior quality and yield. Full article

Idesia polycarpa from Sichuan is a valuable germplasm with high economic potential, but it faces variety scarcity. To address this, this study collected 16 varieties (lines), identifying IpHT1 as a promising parent due to its high oil content (38.5%) and red fruits. Polyploid induction via adding 0.50% colchicine to Murashige and Skoog (MS) medium yielded 520 IpHT1 mutagenized seedlings. Subsequently, flow cytometry (FCM) was performed on 401 morphologically variant seedlings which had been initially screened, resulting in the identification of 15 suspected triploids, 35 suspected tetraploids, and 3 chimeras. Furthermore, fluorescence in situ hybridization (FISH) analysis found that the probe (AG₃T₃)₃ had terminal signals at both ends of each chromosome, allowing for the counting of 42 chromosomes in diploids and 84 in tetraploids. The probe 5S rDNA showed 2, 3, and 4 hybridization signals in the interphase nuclei of diploid, triploid, and tetraploid cells, respectively, but the probe (GAA)₆ failed to produce any signal on I. polycarpa chromosomes. Ultimately, 18 polyploids were selected, including 7 triploids and 11 tetraploids. Triploids and tetraploids showed significant leaf morphological and physiological differences from diploids. Consequently, this study successfully established a polyploid breeding system for I. polycarpa, thereby enhancing its genetic diversity and breeding potential. Full article

Flower and inflorescence architecture play fundamental roles in crop seed formation and final yield. Sesame is an ancient oilseed crop. Exploring the genetic mechanisms of inflorescence architecture and developmental characteristics is necessary for high-yield breeding improvements for sesame and other crops. In this study, we performed a genetic analysis of the sesame mutant css1 with a malformed corolla and small seed size that was mutagenized by ethyl methanesulfonate (EMS) from the cultivar Yuzhi 11. Inheritance analysis of the cross derived from css1 mutant × Yuzhi 11 indicated that the mutant traits were controlled by a single recessive gene. Based on the genome resequencing of 48 F₂ individuals and a genome-wide association study, we determined SNP9_15914090 with the lowest p value was associated with the split corolla and small seed size traits, which target gene Sigif1 (GRF-Interacting Factor 1). SiGIF1 contains four exons and encodes a coactivating transcription factor. Compared to the wild-type allelic gene SiGIF1, Sigif1 in the mutant css1 has a splice donor variant at the exon2 and intron2 junction, which results in incorrect transcript splicing with a 13 bp deletion in exon2. The expression profile indicated that SiGIF1 was highly expressed in the flower, ovary, and capsule but lowly expressed in the root, stem, and leaf tissues of the control. In summary, we identified a gene, SiGIF1, that regulates flower organs and seed size in sesame, which provides a molecular and genetic foundation for the high-yield breeding of sesame and other crops. Full article

Camellia oleifera C. Abel is a woody oil crop with multiple purposes. This study aims to investigate the mutagenic effects of ⁶⁰Co-γ radiation on C. oleifera seedlings and to screen anthracnose-resistant mutants. Two C. oleifera varieties were investigated: ‘Xianglin 1’ (XL1) and ‘Xianglin 210’ (XL210). Seeds were irradiated with 0 Gy, 30 Gy, 50 Gy, and 80 Gy of ⁶⁰Co-γ, and after one year of planting, the mutagenic lines were studied, and disease-resistant mutants were screened. Results showed that as the radiation intensity was increased, the emergence percentage of both C. oleifera XL210 and XL1 was significantly decreased. Radiation significantly changed the SOD and POD activities in both varieties. Furthermore, 80 Gy irradiated lines showed reduced anthracnose resistance in both varieties. However, 50 Gy irradiated lines showed enhanced disease resistance in XL210 while reducing it in XL1. The 30 Gy irradiated lines did not affect the disease resistance of either variety. Colletotrichum gloeosporioides infection tests were conducted on 94 mutant C. oleifera seedlings, resulting in 8 highly resistant mutants (A3, A8, A10, A19, A21, A32, A35, B17) and 3 susceptible mutants (A4, B15, B27) in XL210 and XL1. Differences in SOD and POD activities led to variations in disease resistance among different mutants. Additionally, the expression levels of CoSOD1, CoPOD, CoIDD4, and CoWKRY78 were varied among the different mutants. This study delivers the screening of disease-resistant mutants in C. oleifera through mutagenic breeding, providing material for the development of new C. oleifera varieties and serving as a resource for further research in mutagenic breeding. Full article

Husk tomatoes are used in salsa and traditional medicine to alleviate illnesses. Market demand requires husk tomato varieties with improved agronomic and physicochemical health benefits. Mutagen application alters plant genomes, creating new traits and genetic diversity. The efficacy of EMS (ethyl methanesulfonate) was examined for morphology, bioactive compounds, and phytochemical improvement. Three husk tomato genotypes representing Physalis philadelphica and Physalis ixocarpa underwent two hours of 1.4% EMS. In addition to yield and yield-related properties, total phenol, antioxidant activity, chlorophyll a and b levels in leaves and fruits, and phytochemical concentrations of Na, Mg, Ca, Mn, Fe, Cu, and K in fruits were measured. Genotype-dependent morphological changes were found. The mutants C1T6 (85 cm) and C1T7 (87.60 cm) were shorter than Control C1 (102 cm). The highest yield was 5.80 g for C1T5; Control C1 produced 3.08. The mutant C2T6 produced the most (5.99 g) compared to its control (2.85 g). Mutants had higher total phenol, antioxidant activity, and leaf/fruit chlorophyll. C1T2 had the highest antioxidant activity (1.19 ng/µL). C2T1 outperformed Control C2 at 1.54 ng/µL phenolic content. C3T2 had the highest Ca content (1822 µg/g), while Control C3 had 861.20 µg/g. Mutations altered phytochemical composition, which can be used to generate nutritionally superior husk tomato varieties. Additionally, scientists will be able to study mutants with advantageous morphological and biochemical traits, enabling extensive research. Furthermore, the mutants will serve as a genetic repository for the progression of breeding procedures. Full article

To investigate the effect and mechanism of plasma-activated water (PAW) on Aspergillus niger, PAW was prepared using a needle array–plate dielectric barrier discharge plasma system. The concentrations of long-lived reactive oxygen and nitrogen species (RONS), namely, H₂O₂, NO₂⁻, and NO₃⁻, in the PAW were 48.76 mg/L, 0.046 mg/L, and 172.36 mg/L, respectively. Chemically activated water (CAW) with the same concentration of long-lived RONS was also prepared for comparison. A. niger A32 was treated with PAW and CAW. After treatment, the treated strains were observed and analyzed with scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to screen probable mutants. The results indicated that the pH, conductivity, and ORP values of PAW were 2.42, 1935 μS/cm, and 517.07 mV, respectively. In contrast, the pH and ORP values of CAW were 6.15 and 301.73 mV, respectively, which differed significantly from those of PAW. In addition, the conductivity of CAW showed no change. SEM and TEM analyses revealed that A. niger A32 treated with CAW exhibited less damage compared with the control. In contrast, A. niger A32 treated with PAW showed significant shrinkage, deformation, and exudate attachment over time. Following PAW treatment, after four passages, a high cellulase-producing stable mutant strain A-WW5 was screened, exhibiting a filter paper enzyme activity of 29.66 U/mL, a cellulose endonuclease activity of 13.79 U/mL, and a β-glucosidase activity of 27.13 U/mL. These values were found to be 33%, 38%, and 2.1% higher than those of the original fungus sample, respectively. In total, 116 SNPs and 61 InDels were present in the genome of the mutant strain A-WW5. The above findings indicate that the impact of PAW on A. niger is not only attributed to long-lasting H₂O₂, NO₂⁻, and NO₃⁻ particles but also to other short-lived active particles; PAW is expected to become a new microbial breeding mutagen. Full article