Molecular Breeding最新文献

Clubroot, caused by Plasmodiophora brassicae, is a globally pervasive soil-borne disease that poses a significant challenge primarily in cruciferous crops. However, the scarcity of resistant materials and the intricate genetic mechanisms within cabbage present major obstacles to clubroot resistance (CR) breeding. In our previous research, we developed an Ogura CMS cabbage variety, "17CR3", which harbors the CRa gene, crucial for CR. The fertility of this variety can be restored through crossing with an Ogura cytoplasmic male sterile (CMS) restore line. In the current investigation, offspring from fertile hybrids were utilized as donor parents in backcrossing with five cabbage inbred lines, with the goal of introducing the CRa gene into elite cabbage cultivars possessing superior agronomic traits. Following five years of continuous field selection combined with molecular marker-assisted selection (MAS), we successfully developed BC₄ individuals exhibiting excellent agronomic traits and diverse genetic backgrounds. Whole-genome resequencing revealed a mere 54,213 SNP differences between the genetic makeup of BC₄ individuals and their recurrent parents. The results of inoculation identification demonstrated a high degree of co-segregation between the CRa-specific marker KBrH129J18 and resistance to Plasmodiophora brassicae in both inoculated resistant seedlings and cabbage plants harboring CRa across three distinct regions of China. Additionally, results from Semi-Quantitative RT-PCR experiments revealed minimal to no expression of CRa in the majority of susceptible individuals, underscoring the pivotal role of CRa in conferring CR. Moreover, BC₃ individuals resulting from the cross between "SK308" and "18CR3", which carried CRa, exhibited resistance to clubroot under the natural conditions of disease-prone fields in Wulong, China. In summary, through a combination of traditional breeding methods and MAS, we successfully bred five cabbage inbred lines carrying the CRa gene from diverse genetic backgrounds, thereby establishing a robust foundation for their integration into breeding programs.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-024-01532-2.

Chickpea (Cicer arietinum. L) holds the esteemed position of being the second most cultivated and consumed legume crop globally. Nevertheless, both biotic and abiotic constraints limit chickpea production. This legume is sensitive to heat stress at its reproductive stage leading to reduced flowering, flower abortion, and lack of pod formation, therefore emerging as a major limiting factor for yield. Chickpea, predominantly cultivated in semi-arid regions, is frequently subjected to high-temperature stress, which adversely affects its growth and yield. Given the escalating impacts of climate change, the development of heat-tolerant chickpea genotypes is imperative and can be achieved through the integration of advanced biotechnological approaches. The appropriate solution devised by some researchers is the modification of genetic architecture by targeting specific genes associated with tolerance to heat stress and harnessing them in the development of more robust chickpea varieties. Besides this, multi-omics strategies (Genomics, Transcriptomics, Proteomics, and Metabolomics) have made it easier to reveal the distinct genes / quantitative trait loci (QTLs) / markers, proteins, and metabolites correlated with heat tolerance. This review compiles noteworthy revelations and different tactics to boost chickpea tolerance under heat temperatures.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-025-01538-4.

Plant diseases caused by pathogens and pests lead to crop losses, posing a threat to global food security. The secretory pathway is an integral component of plant defense. The exocyst complex regulates the final step of the secretory pathway and is thus essential for secretory defense. In the last decades, several subunits of the exocyst complex have been reported to be involved in plant defense, especially Exo70s. This comprehensive review focuses on the functions of the exocyst Exo70s in plant immunity, particularly in recognizing pathogen and pest signatures. We discussed Exo70's interactions with immune receptors and other immune-related proteins, its symbiotic relationships with microbes, and its role in non-host resistance. Finally, we discussed the future engineering breeding of crops with resistance to pathogens and pests based on our current understanding of Exo70s.

Spot blotch (SB), a prevalent foliar disease of barley, is caused by the hemibiotrophic fungal pathogen Bipolaris sorokiniana. Predominately occurring in humid growing regions worldwide, SB can result in yield losses of up to 30%. Genetic resistance remains the most effective strategy for disease management; however, most Australian barley cultivars exhibit susceptibility despite the previous identification of major resistance loci. This study investigates the genetic architecture underlying spot blotch resistance within an Australian barley breeding program. Resistance was assessed at both the seedling and adult growth stages using a single conidial isolate (SB61) across two consecutive years. A total of 337 barley lines were genotyped with 16,824 polymorphic DArT-seq™ markers. Two mapping approaches were employed: a single-marker genome-wide association study (GWAS) and a haplotype-based local genomic estimated breeding values (Local GEBV) approach. Both methodologies identified two major resistance-associated regions on chromosomes 3H and 7H, effective across growth stages. Additionally, the haplotype-based Local GEBV approach revealed resistance-associated regions on 1H, 3H, and 6H that were not detected by GWAS. Haplotype stacking analysis underscored the critical role of the 7H region for adult-plant resistance when combined with other resistance haplotypes, suggesting significant gene-by-gene interactions and highlighting the complex, quantitative nature of spot blotch resistance. This research confirms the presence of key resistance loci within Australian barley breeding populations, provides novel insight into the genetic architecture of spot blotch resistance, and emphasises the potential to enhance resistance through haplotype stacking and whole-genome prediction approaches.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-025-01537-5.

Previous studies illustrated that two banana GA20 oxidase2 (MaGA20ox2) genes, Ma04g15900 and Ma08g32850, are implicated in controlling banana growth and development; however, the biological function of each gene remains unknown. Ma04g15900 protein (termed MaGA20ox2f in this article) is the closest homolog to the Rice SD1 (encoded by 'green revolution gene', OsSD1) in the banana genome. The expression of MaGA20ox2f is confined to leaves, peduncles, fruit peels, and pulp. Knockout of MaGA20ox2f by CRISPR/Cas9 led to late flowering and low-yielding phenotypes. The flowering time of ΔMaGA20ox2f #1 and ∆MaGA20ox2f #2 lines was delayed approximately by 61 and 58 days, respectively, while fruit yield decreased by 81.13% and 76.23% compared to wild type under normal conditions. The endogenous levels of downstream products of GA20 oxidase, GA15 and GA20, were significantly reduced in ∆MaGA20ox2f mutant shoots and fruits, but bioactive GA1 was only significantly reduced in the mutant fruits. Quantitative proteomics analysis identified 118 up-regulated proteins and 309 down-regulated proteins in both ΔMaGA20ox2f #1 and ∆MaGA20ox2f #2 lines, compared to wild type, with the down-regulated proteins primarily associated with photosynthesis, porphyrin and chlorophyll metabolism. The decreased chlorophyll contents in ΔMaGA20ox2f #1 and ∆MaGA20ox2f #2 lines corroborated the findings of the proteomics data. We propose that photosynthesis inhibition caused by lower chlorophyll contents in ΔMaGA20ox2f mutant leaves and GA1 deficiency in ΔMaGA20ox2f mutant fruits may be the two critical reasons contributing to the late flowering and low-yielding phenotypes of ΔMaGA20ox2f mutants.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-024-01523-3.

This study investigated the potential of extended irradiation combined with immature embryo culture techniques to accelerate generation advancements in safflower (Carthamus tinctorius L.) breeding programs. We developed an efficient speed breeding method by applying light-emitting diodes (LEDs) that emit specific wavelengths, alongside the in vitro germination of immature embryos under controlled environmental conditions. The experimental design for light treatments followed a 2 × 4 completely randomized factorial design with four replications, incorporating two safflower varieties, Remzibey-05 and Dinçer, and four LED treatments (white, full-spectrum, red + blue + white, and control). A lighting regimen of 22 h of light and 2 h of darkness was applied for all the LED treatments, whereas the control received 18 h of light and 6 h of darkness. Additionally, the immature embryo culture experiment used a 2 × 2 × 4 factorial arrangement, assessing two safflower cultivars, two media types, and four embryo developmental stages, with three replications. The parameters evaluated included plant height, branch number, seed number per plant, seed number per head, time to flower initiation, time to 50% flowering, time to harvest, and germination percentage of in vitro cultured immature embryos at various developmental stages. The harvest time among the light treatments ranged from 50.62 to 73.12 days, with the shortest time achieved under the red + blue + white LED combination and the longest under the control treatment. The plant height, number of seeds per plant, and number of seeds per head were highest under the full-spectrum LED, control and red + blue + white LED combinations, respectively. Immature embryos rescued at 10 days post-pollination presented a 57% germination rate, with an increasing trend in germination as the number of days post-pollination increased. The germination rates did not significantly differ across varieties or hormone treatments. This study demonstrated the potential to achieve six generations per year by combining prolonged illumination with targeted LED lighting and immature embryo culture techniques. These findings provide valuable insights for optimizing safflower growth and development and advancing speed breeding in controlled environments.

Genomic selection-based breeding programs offer significant advantages over conventional phenotypic selection, particularly in accelerating genetic gains in plant breeding, as demonstrated by simulations focused on combating Fusarium head blight (FHB) in wheat. FHB resistance, a crucial trait, is challenging to breed for due to its quantitative inheritance and environmental influence, leading to slow progress using conventional breeding methods. Stochastic simulations in our study compared various breeding schemes, incorporating genomic selection (GS) and combining it with speed breeding, against conventional phenotypic selection. Two datasets were simulated, reflecting real-life genotypic data (MASBASIS) and a simulated wheat breeding program (EXAMPLE). Initially a 20-year burn-in phase using a conventional phenotypic selection method followed by a 20-year advancement phase with three GS-based breeding programs (GSF2F8, GSF8, and SpeedBreeding + GS) were evaluated alongside over a conventional phenotypic selection method. Results consistently showed significant increases in genetic gain with GS-based programs compared to phenotypic selection, irrespective of the selection strategies employed. Among the GS schemes, SpeedBreeding + GS consistently outperformed others, generating the highest genetic gains. This combination effectively minimized generation intervals within the breeding cycle, enhancing efficiency. This study underscores the advantages of genomic selection in accelerating breeding gains for wheat, particularly in combating FHB. By leveraging genomic information and innovative techniques like speed breeding, breeders can efficiently select for desired traits, significantly reducing testing time and costs associated with conventional phenotypic methods.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-024-01527-z.

Pre-harvest sprouting (PHS) of wheat (Triticum aestivum L.) is one of the complex traits that result in rainfall-dependent reductions in grain production and quality worldwide. Breeding new varieties and germplasm with PHS resistance is of great importance to reduce this problem. However, research on markers and genes related to PHS resistance is limited, especially in marker-assisted selection (MAS) wheat breeding. To this end, we studied PHS resistance in recombinant inbred line (RIL) population and in 171 wheat germplasm accessions in different environments and genotyped using the wheat Infinium 50 K/660 K SNP array. Quantitative trait loci (QTL) mapping and genome-wide association studies (GWAS) identified 59 loci controlling PHS. Upon comparison with previously reported QTL affecting PHS, 16 were found to be new QTL, and the remaining 43 loci were co-localized with QTL from previous studies. We also pinpointed 12 candidate genes within these QTL intervals that share functional similarities with genes previously known to influence PHS resistance. In addition, we developed and validated two kompetitive allele-specific PCR (KASP) markers within the chromosome 7B region identified by linkage analysis. These QTL, candidate genes, and the KASP marker identified in this study have the potential to improve PHS resistance of wheat, and they may enhance our understanding of the genetic basis of PHS resistance, thus being useful for MAS breeding.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-024-01526-0.