Molecular Breeding最新文献

Plant height is one of the most critical factors influencing wheat plant architecture, and the application of Green Revolution genes has led to a reduction in plant height and an increase in yield. Discovering new dwarfing genes and alleles can contribute to enhance the genetic diversity of wheat. Here we obtained an EMS induced dwarf wheat mutant je0166 with increased grain weight, which exhibited a reduction in plant height ranging from 46.47% to 49.40%, and its cell length was shorter. The mutant je0166 was sensitive to exogenous gibberellin, but its sensitivity was lower than that of its wild type. Genetic analysis on plant height and gene mapping located the target region to a 4.07 cM interval on chr. 4AL. Within this interval, we identified a co-segregated mutation in Rht-A1h, which is a novel allele of the Green Revolution gene Rht-A1. We also found large fragment inversions in the genetic map of the mutant. The novel allele diversifies natural allelic variations and could be utilized in future wheat improvement. Furthermore, we demonstrated that chemical mutagen treatment led to large fragment inversion.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-024-01515-3.

Coleoptile length, in wheat, is a significant agronomic trait impacting yield by facilitating the successful establishment of seedlings. In arid regions, varieties possessing longer coleoptile can evade harsh conditions by deep sowing, paving the way for improved yield. However, the study of genes involved in coleoptile development is insufficient. In this study, a high-density 660 K SNP array was used for genome-wide association study (GWAS) on coleoptile length in 150 wheat varieties. The findings revealed the detection of 353 significantly associated SNPs across all environments. The integration of linkage disequilibrium analysis and haplotype analysis mined 23 core QTLs capable responsible for the stable regulating coleoptile length in wheat. In wheat varieties characterized by extended coleoptile length, 6,600, 11,524, and 6,059 genes were found to be differentially expressed at three distinct developmental stages within the coleoptile, respectively. Through GWAS, gene expression levels, and functional annotation, we concluded the identification of two candidate genes (TraesCS2B02G423500, TraesCS2B02G449200) regulating wheat coleoptile length. By employing WGCNA and protein interactions prediction, discovered that the 19 genes were found to interact with candidate genes and participate in plant hormone metabolism and signaling, cell elongation or proliferation, which collectively contributing to coleoptile elongation. Additionally, two KASP markers were developed which can be used in breeding. These results offer a basis for understanding the genetic regulatory network responsible for wheat coleoptile length formation. The QTLs and candidate genes identified in this study can be further utilized for genetic improvement of wheat coleoptile length.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-024-01520-6.

Citrus Huanglongbing (HLB) is a devastating disease spread by citrus psyllid, causing severe losses to the global citrus industry. The transmission of HLB is mainly influenced by both the pathogen and the citrus psyllid. The unculturable nature of the HLB bacteria (Candidatus Liberibacter asiaticus, CLas) and the susceptibility of all commercial citrus varieties made it extremely difficult to study the mechanisms of resistance and susceptibility. In recent years, new progress has been made in understanding the virulence factors of CLas as well as the defense strategies of citrus host against the attack of CLas. This paper reviews the recent advances in the pathogenic mechanisms of CLas, the screening of agents targeting the CLas, including antimicrobial peptides, metabolites and chemicals, the citrus host defense response to CLas, and strategies to enhance citrus defense. Future challenges that need to be addressed are also discussed.

Cabbage is a widely cultivated leafy vegetable, but head rot disease caused by the fungus Sclerotina sclerotiorum can seriously reduce its yield and quality. There are currently not any cabbage varieties that are completely immune to the disease, but its wild relative Brassica incana is very resistant. In this study, cabbage resistance was improved by backcrossing a highly resistant B. incana accession (C01) with a susceptible cabbage cultivar (F416). Although C01 lacks a leafy head formation, highly resistant plants appeared in the fourth backcrossing generation (BC₄F₁) that had a similar leafy head to F416. The individuals with strong resistance were purified by self-pollination. Inbred lines that maintained a relatively stable resistance at BC₄F₃ were developed and had significantly higher resistance to S. sclerotiorum than F416. In addition, hybrids created from a cross between of BC₄F₃ and E2 had higher resistances to S. sclerotiorum and similar agronomic characteristics to Xiyuan 4. The results demonstrated that new F416 lines that are resistant to S. sclerotiorum can be developed, and that these lines could be used to create new cabbage varieties with superior head rot resistance.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-024-01513-5.

Chrysanthemums are versatile ornamental plants, and improving leaf and flower traits is an important breeding objective. Distant hybridization is a powerful method for plant breeding and genetic improvement, whereas the genetic basis in interspecific F₁ progeny of chrysanthemums needs to be better understood for breeding purposes. In this study, the leaf and floral traits of the 273 reciprocal interspecific F₁ hybrids of diploid C. dichrum (YSJ) and C. nankingense (JHN) were analyzed along with their SNP-derived genetic structure to elucidate the influence of differences in genetic background between the parents on the hybrid performance. We then performed a genome-wide association analysis (GWAS) to reveal the investigated traits' genomic loci and candidate genes. Considerable phenotypic variation (8.81% ~ 55.78%) and heterosis with transgressive segregation in both directions were observed in the reciprocal progenies. We observed a higher level of phenotypic variation in JHN × YSJ rather than in YSJ × JHN. Also, a significant reciprocal effect was observed for most examined traits. Based on the SNP data, we separated the hybrid progenies into three groups (I, II, and III), albeit imperfectly dependent on the cross directions, except for some reciprocal hybrids clustering into group II. Group I from YSJ × JHN and Group III from YSJ × JHN differed with contrasting F _ST and π ratios, indicating the genetic changes in the reciprocal populations. The outcome of GWAS via the IIIVmrMLM method detected 339 significant quantitative trait nucleotides (QTNs) and 40 suggestive QTNs, and the phenotypic variation explained by a single QTN ranged from 0.26% to 7.42%. Within 100 kb upstream and downstream of the important QTNs, we discovered 49 known genes and 39 new candidate genes for the investigated leaf and floral traits. Our study provides profound insights into the genetic architecture of reciprocal hybrid progenies of chrysanthemum species, facilitating future breeding activities.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-024-01518-0.

The sorghum inflorescence is consisted of sessile (SS) and pedicellate spikelets (PS). Commonly, only SS could produce seeds and each spikelet produces one single seed. Here, we identified a sorghum mutant, named Double-grain (Dgs), which can produce twin seeds in each pair of glumes. We characterized the developmental process of inflorescence in Dgs and Jinliang 5 (Jin5, a single-seeded variety) using scanning electron microscope (SEM). The results showed that at the stamen and pistil differentiation stage, Dgs could develop two sets of stamens and carpels in one sessile floret, which resulted in twin-seeded phenotype in Dgs. Two F₂ mapping populations derived from the cross between Jin5 and Dgs, and BTx622B and Dgs, were constructed, respectively. The genetic analysis showed that Dgs trait was controlled by a single dominant gene. Through bulk segregation analysis with whole-genome sequencing (BSA-seq) and linkage analysis, Dgs locus was delimited into a region of around 210-kb on chromosome 6, between the markers SSR24 and SSR47, which contained 32 putative genes. Further analysis indicated that Sobic.006G249000 or Sobic.006G249100 may be responsible for the twin-seeded phenotype. This result will be useful for map-based cloning of the Dgs gene and for marker-assisted breeding for increased grain number per panicle in sorghum.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-024-01511-7.

Deterioration of rice (Oryza sativa L.) affects grain quality and seed viability during storage. Lipoxygenase (LOX), a key enzyme in lipid metabolism, directly affects the rate of ageing. Here, we found that knock-out of lipoxygenase gene OsLOX1 by CRISPR/Cas9 delayed loss of seed viability and quality. Transcriptome analysis showed that during storage, OsLOX1 affected transcription of multiple genes, including genes related to lipid metabolism and antioxidant pathways such as phosphatase and acetaldehyde dehydrogenase, which may regulate the seed storability. The genes significantly down- and up-regulated only in Ningjing 4 after NA for 13 months and 3 days of AA suggesting that OsLOX1 likely promoted seed viability in rice by balancing ageing and storage related genes, and regulated the seed storability through the amino acid synthesis and metabolic pathways. Moreover, knock-out of OsLOX1 without CRISPR/Cas9 not only improved the seed viability, but also had little impact on agronomic traits. More importantly, the OsLOX1 knock-out lines were approved in 2019 (Agricultural Foundation of China Report No. 770). Collectively, our study showed that knock-out of OsLOX1 is beneficial for prolongation of seed viability and can be directly applied to agricultural production.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-024-01506-4.

Crispness stands as a pivotal criterion in assessing apple texture, widely cherished by consumers. Yet, owing to its multifaceted nature, crispness remains a formidable challenge in artificial enhancement efforts. To expedite the early and precise evaluation of apple crispness, this study centered on a hybrid population derived from 'Fuji' and 'Pink Lady' cultivars, showcasing segregating crispness traits. We conducted measurements of flesh water content, cellular anatomical morphology, and employed a texture analyzer to assess mechanical properties of the offspring flesh. Integrating these three dimensions, we conducted a comprehensive analysis of quantitative characteristics of apple crispness, juxtaposed with sensory evaluation. Utilizing BSA-seq technology, we scrutinized extreme phenotypic individuals, revealing QTL loci intricately linked to the aforementioned dimensions, and subsequently developed Key Allele-Specific PCR (KASP) markers. These markers underwent validation in hybrid populations of 'Hanfu' x 'Pink Lady' and 'Hanfu' x 'Honey Crisp'. Our findings underscored significant correlations between mechanical properties, water content, and cell size with crispness. Higher mechanical properties and water content, alongside smaller cell size, correlated with firmer flesh texture; moderate mechanical properties, and elevated water content and cell size, with crisper texture; whereas lower mechanical properties, water content, and cell size implied softer flesh.The study yielded KASP markers effectively reflecting flesh mechanical properties (SNP_24399345), water content (SNP_8667563), and cell size (SNP_15566229). Comprehensive analysis of these markers identified CC-CC-TT as an effective identifier of soft flesh individuals; while GG-TC-TT and GG-CC-TT combinations better represented individuals with harder flesh. The Crunchy subclass could be discerned by combinations of GG-TC-TC, GG-TC-CC, GG-TT-TC, and GG-TT-CC. These findings furnish effective molecular markers for the genetic enhancement of apple crispness, bearing significant implications for the cultivation of novel apple varieties.

Supplementary information: The online version contains supplementary material available at 10.1007/s11032-024-01509-1.

Bud endodormancy in deciduous fruit trees is an adaptive trait evolved by selection for the capacity to survive unfavorable environmental conditions. Deciduous trees require a certain amount of winter chill named chilling requirement (CR) to promote bud endodormancy release. In recent decades, global warming has endangered the chill accumulation in deciduous fruit trees. Developing low-CR cultivars is a practical way to neutralize the effect of climate changes on the cultivation and distribution of deciduous fruit trees. In this review, we focus on the effect of chilling accumulation on bud endodormancy release and the genetic mechanisms underlying the chilling requirement in deciduous fruit trees. Additionally, we put forth a regulatory model for bud endodormancy and provide prospective directions for future research in deciduous fruit trees.