Search Results (212)

Background: Male sterility is a critical trait for large-scale hybrid rice seed production, yet the genetic and molecular regulatory networks governing tapetal degradation during anther development remain incompletely understood. This study aimed to clone the causal gene underlying a novel rice non-pollen male sterility mutant and elucidate its role in tapetal development and microsporogenesis. Methods: The nms1 (non-pollen male sterility 1) sterile mutant was screened from the ethyl methanesulfonate (EMS)-mutagenized progeny of the elite indica restorer line Shuhui 498 (R498). Map-based cloning and whole-genome resequencing-assisted bulked segregant analysis were used to identify the causal variant. Gene function was verified via cytological observation, genetic complementation testing, RNA sequencing, and quantitative real-time PCR (qRT-PCR) to profile sterility-associated transcriptional changes. Results: Gene mapping identified a T635A single-nucleotide substitution within OsR498G0305626400.01 on chromosome 3, which encodes a strictosidine synthase-like protein. This nucleotide alteration causes a Val212Glu amino acid change and is associated with delayed tapetal degradation and pollen abortion. Transgenic complementation experiments verified that functional NMS1 restores fertility in nms1 mutant plants. Spatiotemporal expression analysis showed predominant NMS1 expression in late-developing spikelets. Furthermore, combined RNA sequencing and qRT-PCR analyses demonstrated that loss of NMS1 function leads to significant transcriptional dysregulation of key regulators of programmed cell death (PCD) in the tapetum (PTC2, TIP2) and pollen wall biosynthesis genes (TIP3, OsMS2). Conclusions: This study demonstrates that NMS1 plays a crucial role in coordinating tapetal degradation and microspore development in rice. The discovered functional SNP of NMS1 provides a novel theoretical foundation and a valuable sterile genetic resource for hybrid rice breeding. Full article

The induction of staminate flowers in genetically female Cannabis sativa is widely used for feminized seed production, yet its anatomical and ontogenetic basis remains poorly understood. This study examined silver thiosulfate (STS)-induced masculinization in genetically female plants of C. sativa cv. ‘Pasionaria S’ using stereomicroscopy, light microscopy, confocal laser scanning microscopy, pollen viability assays, and open-pollination tests. STS redirected floral sexual identity within the conserved architecture of the female reproductive shoot. Staminate floral meristems were first detected at 7 days post-treatment, while previously initiated pistillate flowers persisted; by 21 days, the reproductive apex was dominated by staminate structures. Induced male flowers corresponded to type II unisexual flowers, with early staminal primordia and no evidence of gynoecial primordia. Three trajectories were identified: fertile male flowers with normal anther development and viable pollen, sterile flowers with collapsed anthers and disrupted microsporogenesis, and occasional mixed flowers with localized androecial expression. Pollen viability reached 54%, and open pollination confirmed seed formation. These results show that STS-induced masculinization is a staged and heterogeneous redirection of floral meristem identity. Full article

Camellia oleifera (Theaceae) is valued for its high seed oil content and economic significance. The use of male sterility is important in plant hybrid breeding. Currently, in-depth research on male sterility in C. oleifera remains limited. Previous studies have primarily focused on breeding characteristics and taxonomy. In this study, we examined normal anther development using paraffin sectioning and identified five distinct types of abnormal anther dehiscence in C. oleifera using scanning electron microscopy (SEM) and light microscopy (LM). We analyzed the morphology of both normal pollen and pseudopollen cells in these abnormal anthers. Notably, among the F1 hybrids of Camellia yuhsienensis × C. oleifera, accession ‘YS-15’ exhibited limited anther dehiscence, whereas accession ‘YS-21’ showed complete indehiscence, significantly impeding pollen release. Quantitative analysis revealed a gradual decline in the number of both normal pollen grains and pseudopollen cells across the five abnormal anther types. The normal pollen count in these anthers was significantly lower than in wild-type counterparts. Specifically, the number of pseudopollen cells gradually decreased among the five F1 hybrid accessions (‘YS-5’, ‘YS-8’, ‘YS-13’, ‘YS-15’, and ‘YS-21’), with no pseudopollen cells detected in the latter two accessions. This study identifies a novel male-sterile germplasm in C. oleifera, providing valuable genetic resources for hybrid breeding and advancing research on male sterility. Full article

MYB transcription factors (TFs) play essential roles in diverse biological processes, including anther and pollen development, vegetative growth, seed development and germination, and stress responses. However, functional characterization of MYB TFs in maize (Zea mays) lags far behind that in Arabidopsis thaliana and Oryza sativa. In this study, we performed a genome-wide identification of 196 maize MYB TFs, along with phylogenetic analysis and Gene Ontology (GO) annotation. To bridge the knowledge gap, we established an integrated cross-species comparative workflow that systematically maps functionally characterized MYB TFs from Arabidopsis and rice to their maize orthologs. By coupling this homology-based approach with spatiotemporal expression profiling of developing anthers across multiple inbred lines, we prioritized candidate MYB TFs likely involved in anther and pollen development. This integrated strategy provides a useful reference for translating the rich functional knowledge accumulated in model plants to crops with less-characterized genomes. Our study not only establishes a solid foundation for the functional investigation of maize MYB TFs, but also offers promising targets for the mechanistic dissection and molecular breeding application of male sterility in maize. Full article

Hybridization between sugarcane (Saccharum spp.) and its wild relative Erianthus rockii offers a promising route to broadening the narrow genetic base of modern cultivars, but the authenticity and chromosome inheritance patterns of such hybrids remain poorly understood. In this study, we combined molecular marker (tetra-primer ARMS-PCR) and cytogenetic (genomic in situ hybridization, GISH) approaches to verify hybridity and track chromosome transmission in 24 F₁ and 12 BC₁ progeny. The F₁ hybrids exhibited a strict n + n transmission pattern, receiving exactly 15 chromosomes from E. rockii. When F₁ plants were used as the male parent in backcrosses, no BC₁ seeds were obtained due to complete pollen sterility. Remarkably, when F₁ plants served as the female parent, all 12 BC₁ clones retained the entire set of 15 E. rockii chromosomes intact, following an unconventional 2n + n pattern. These findings reveal a strong parent-of-origin effect and, for the first time, demonstrate that the whole E. rockii chromosome complement can be stably transmitted into backcross progeny without loss or recombination. This opens a direct route for introgressing complete wild genomes into sugarcane breeding lines, preserving complex polygenic traits and guiding rational crossing strategies. Full article

Maize hybrid seed production is a core factor in increasing maize yield. It is the key to ensure seed purity to remove tassels from female plants. This paper analyzes the inherent connections between seed production agronomy, biomechanics, computer vision, and intelligent devices at the system engineering level. The paper first elaborates on the role of crop growth models and genetic male sterility techniques in expanding the time window of mechanical operations. Secondly, based on the perception decision execution framework, this paper discusses how the biomechanical characteristics of male spikes directly determine the dynamic parameter design of the male removal actuator; in-depth analysis was conducted on the performance and limitations of deep learning algorithms in handling lighting changes, leaf occlusion, and high-throughput recognition in unstructured field environments. In addition, this paper compares the technical game between the detasseling success rate and leaf damage rate of two mainstream execution paths, cutting and extraction. This review highlights that future research should focus on the development of lightweight intelligent operation platforms and full-life-cycle digital decision-making systems, to realize high-efficiency and low-damage precision detasseling of seed maize. Full article

The SHAGGY-like kinase (SK) gene family regulates diverse developmental and abiotic stress response processes in plants. Although genome-wide analyses of SKs have been conducted in model plants such as Arabidopsis thaliana and rice, their characterization in the economically important crop Brassica rapa remains limited. In this study, we conducted a systematic genome-wide analysis of SK genes in three Brassica species. A total of 18, 16, and 18 SK members were identified in B. rapa, B. nigra, and B. oleracea, respectively, and phylogenetic analysis classified them into four distinct clades. Expression profiling revealed that BrSKβ-1 and BrSKβ-2 were specifically expressed in fertile floral buds, suggesting their critical roles in pollen development. Furthermore, co-expression analysis indicated that both genes were co-expressed with key regulators involved in pollen development, pollen sperm cell differentiation and pollen tube growth. Loss of BrSKβ-2 via CRISPR/Cas9 resulted in 25–65% pollen abnormality and reduced the germination rate of normal-appearing pollen to only 10%, confirming its essential role in male fertility. Together, these findings provide a comprehensive characterization of the SK gene family in Brassica and position BrSKβ-2 as a promising candidate for gene editing-based male sterility systems in B. rapa and related crops. Full article

High-temperature (HT) stress during flowering causes male sterility and yield loss in soybean. MYB transcription factors are key regulators under abiotic stress, yet their function and mechanism in regulating male fertility under HT stress in soybean are not fully understood. In this study, a MYB transcription factor GmMYB21a in soybean was identified. GmMYB21a was induced by HT stress in soybean restorer line and was specifically expressed in pollen. Through overexpression and knockout experiments, we demonstrated that GmMYB21a positively regulated pollen viability and germination under HT stress. Overexpression of GmMYB21a significantly enhanced these traits in restorer line, whereas knockout plants exhibited the opposite effect. Transcriptome sequencing revealed that GmMYB21a overexpression upregulated numerous stress-responsive genes, particularly those involved in flavonoid biosynthesis and sugar metabolism. In addition, molecular experiments confirmed that GmMYB21a bound to the promoter of flavonoid synthesis gene GmCHI2-A and promoted its expression. In summary, our research indicated GmMYB21a enhanced the HT-tolerance of male fertility in soybean restorer line through reactive oxygen species scavenging and flavonoid synthesis. This study aims to elucidate the thermotolerance mechanism in soybean male fertility and identify genetic resources for breeding HT-tolerant restorer lines. Full article

Sugar beet (Beta vulgaris L.) is one of the most important sugar crops and potential energy crops in China. The utilization of its heterosis is crucial for breaking through the bottlenecks in yield and quality, while the fertility identification of binary male-sterile lines is the core link to ensure the purity of hybrid seeds. Due to its indeterminate inflorescence, artificial emasculation of sugar beet is not feasible, which significantly increases the difficulty in hybrid seed production. To rapidly and accurately identify the fertility composition of monogerm binary male-sterile lines of sugar beet, ensure the maternal line purity in sugar beet hybrid seed production, and improve breeding efficiency, this study conducted fertility identification using molecular marker technology with 7 monogerm binary male-sterile line germplasm resources (297 plants) provided by three research institutions in different regions of China. Genomic DNA was extracted from young sugar beet leaves by the CTAB method. The cytoplasmic fertility types were identified using the TR1 primer, and the fertility gene composition at the nuclear Rf1 locus was verified by the s17 molecular marker combined with Hap II and Hind III double digestion. The results showed that in the cytoplasmic fertility identification, the proportion of S-type cytoplasm in Lines 2 to 7 reached 100%, indicating stable sterility without maintainer line contamination; Line 1 had 93.33% S-type cytoplasm, mixed with 6.67% N-type cytoplasm. For the nuclear Rf1 locus identification, 93.27% (277 plants) of the tested materials yielded the target 1800 bp band by PCR amplification, which were preliminarily identified as homozygous recessive type. Among them, Lines 1 to 3 all showed a single 1800 bp band pattern, indicating homozygous and consistent nuclear fertility genotypes; 20 plants (6.73%) in Lines 4 to 7 exhibited a composite 1800/1300 bp band pattern, suggesting the presence of restorer allele contamination in some lines. Genotype analysis based on 35 enzyme-digested verification samples revealed that the 4/4 genotype had the highest proportion. This study realized the rapid and accurate identification of cytoplasmic and nuclear fertility in monogerm binary male-sterile lines of sugar beet through molecular marker technology, clarified the fertility purity status of 7 germplasm resources, and verified the application value of this technology in the fertility identification of sugar beet binary male-sterile lines. These results provide a scientific basis and technical support for controlling maternal line purity and improving breeding efficiency in sugar beet hybrid seed production. Full article

Maintaining stable male sterility is fundamental for ensuring the genetic purity and productivity of two-line hybrid wheat. However, unexpected heat events during the fertility-sensitive period can induce fertility restoration in photo-thermo-sensitive male sterile (PTMS) lines, posing a major threat to hybrid seed production. In this study, we identified two BS-type PTMS lines, BS166 and BS192, that consistently maintained sterility under heat stress in a seed-production environment, indicating strong heat-tolerant sterility. To uncover the molecular basis underlying this stability, we compared four BS-type PTMS lines exhibiting contrasting heat responses through field assessments, controlled heat treatments, transcriptome sequencing, and weighted gene co-expression network analysis (WGCNA). A total of 19,105 differentially expressed genes were identified, with the bisque4 module showing a significant correlation with seed setting rate. KEGG enrichment analysis revealed that starch and sucrose metabolism, cutin, suberin, and wax biosynthesis, fatty acid biosynthesis, and plant hormone signal transduction pathways were highly associated with heat-tolerant sterility. Core genes within these pathways displayed transcriptional stability in BS166 and BS192 but were strongly induced in heat-sensitive lines. In situ hybridization and RT-qPCR further confirmed tapetum-specific expression of TaBGLU32 and TaLACS1. Based on these findings, we propose a regulatory model explaining how PTMS lines maintain sterility stability under heat stress. Full article

YUCCA belongs to the flavin-containing monooxygenas and catalyzes the rate-limiting step in endogenous auxin biosynthesis, thereby regulating local auxin homeostasis and participating in diverse aspects of plant growth, development, and physiological processes. However, the relationship between the YUCCA genes and male fertility regulation in wheat remains unclear. In this study, we identified 64 TaYUCCA genes through whole-genome analysis and classified them into three clades, each of which is conserved in motif composition and gene structure. A synteny analysis indicated that family expansion was primarily driven by segmental duplication and tandem duplication, and Ka/Ks analysis suggested that all members are under purifying selection. An analysis of the expression patterns showed that the TaYUCCA genes displayed differential expression across various tissues and reproductive developmental stages. In the temperature-sensitive male-sterile wheat line YS3038, TaYUCCA19, TaYUCCA22, and TaYUCCA25 were specifically highly expressed at the uninucleate pollen stage under fertile conditions. The silencing of TaYUCCA19 resulted in abnormal pollen morphology and a significant reduction in the seed set rate, indicating that it is a key gene required for normal pollen development in wheat. Overall, this study systematically characterizes the wheat YUCCA gene family and provides the first functional evidence of TaYUCCA genes in male reproductive development, offering an important foundation for studies on wheat male sterility mechanisms and the exploitation of heterosis. Full article

Although cytoplasmic male sterility (CMS) is well established in eggplant, CMS-based interspecific hybrids with allied species have not yet been reported or studied. In this study, five previously developed CMS-based interspecific F₁ hybrids between eggplant and Solanum aethiopicum Group Aculeatum (=S. integrifolium) and Group Gilo (=S. gilo), together with their parental lines, were morphologically evaluated for 67 seedling, vegetative, floral, and fruit traits, and their heterosis for vegetative growth was studied. Male fertility was assessed based on anther morphology and pollen viability, while female fertility was evaluated through backcrosses to both parents. The hybrids exhibited predominantly intermediate phenotypes and clustered distinctly from parental lines as confirmed by principal component analysis. Remarkable heterosis was observed for most growth-related traits, indicating favorable nuclear–cytoplasmic interactions despite the use of CMS eggplant lines as maternal parents. All hybrids showed complete male sterility, characterized by non-viable pollen and pronounced anther homeotic alterations, the latter indicating CMS-related effects on male fertility. Female fertility was severely reduced, likely due to meiotic irregularities, as evidenced by the failure of most attempted backcrosses. However, successful recovery of BC₁ progeny after backcrossing one CMS-based F₁ hybrid to S. gilo demonstrates partial reproductive compatibility and provides a genetic bridge for CMS introgression into S. gilo. These results indicate that CMS systems are suitable for eggplant interspecific crosses aimed at vigorous rootstock production and CMS cytoplasm introgression into allied germplasm. Full article

Systems favoring cross-pollination, such as male sterility and female flowering type, are of great importance in the development of new hybrid cultivars and their seed production. The advantages of male sterility are expressed in the production of cheaper and competitive seeds. The presence of this characteristic in watermelon is not common, and in some cases, it is accompanied by negative manifestations. A collection of 150 watermelon genotypes was tested at the Maritsa Vegetable Crops Research Institute, Bulgaria, over the past nine years to search for a genetic source of male sterility. The results revealed that two mutations were found. The first mutation was in a plant of the Asar variety, which formed completely degenerated structures in the place of male and female flowers that were completely sterile. The other mutation affected male flowers, female flowers, and leaf shape. Male flowers produced a small amount of pollen. Female flowers were formed, but they were sterile and aborted at an early stage. The genotype can be propagated by pollination of the normal plants, which in the next generation segregate into mutant—25% and normal—75%. The gene source is phenotyped according to the main characteristics of the fruits and the vegetation period. The mutation found cannot be directly used in a breeding program, but it is of interest for studying this important trait. The success of detecting flowers that are sterile depends on the number of watermelon plants, which, for the conditions of the experiment, amounted to a minimum of 4492 plants at a probability level of P₃—0.95. Full article

Thermosensitive genic male sterility (TGMS) lines are vital for two-line hybrid breeding. However, the molecular mechanism in the reverse TGMS line 05ms in eggplant remains unclear. Weighted gene co-expression network analysis (WGCNA) of RNA-seq data revealed modules correlated with fertility conversion enriched in carbohydrate metabolism, lipid metabolism, and mRNA surveillance pathways. Hub genes within these modules were predominantly associated with sugar-related processes, fatty acid metabolism, and nucleotide processing. BSA-seq defined candidate genomic intervals. Integrated analysis of BSA-seq intervals and transcriptomic data identified a candidate gene, SmHTH, with consistently lower expression in 05ms compared to S63. Its homologs exhibited temperature-induced expression, possibly compensating for SmHTH deficiency under high temperatures to restore fertility. The homologs co-expressed with three transcription factors are likely intricately linked to this response. We propose a compensatory model demonstrating that low SmHTH expression at low temperatures disrupts key metabolic pathways, causing male sterility. Conversely, elevated expression of homologous genes and transcription factors (TFs) at higher temperatures compensates for the loss of SmHTH function, thereby restoring fertility. The findings of this research not only deepen the theoretical understanding of plant male sterility mechanisms but also provide valuable resources for developing stress-resilient vegetable varieties through modern breeding techniques. Full article

In modern agriculture, heterotic hybrids produced from hybridization of inbred lines, have shown superiority over open-pollinated and pure line varieties due to their morphological homogeneity, synchronized maturity, and yield performance. The worldwide use of heterosis in plant breeding programs has become possible due to the discovery of cytoplasmic male sterility (CMS), a phenomenon that prevents a plant from producing viable pollen. The CMS-Rf genetic systems are commonly used to produce hybrid seeds. Species from primary, secondary, and tertiary gene pools serve as sources of sterility-inducing cytoplasm in different crop plants. In this review, information on the main genetic factors that induce sterility and restore pollen fertility in F₁ hybrids of economically important cereal (rice, sorghum, maize, rye, wheat, pearl millet) and oilseed (sunflower, rapeseeds, mustard) crops are discussed. The genetic data indicate the location of putatively orthologous candidate Rf genes on syntenic chromosomes in evolutionarily related species. The cytological features of male gametophyte development associated with pollen abortion in lines with CMS are highlighted. The problem of heterotic grouping and selecting parental forms based on genetic distance is discussed. The present knowledge on the genetic resources of different cereal and oilseed crops is highly related to the availability of genomic data. Broadening the CMS source pool and the search for new pollen fertility restoration genes are relevant to avoid cytoplasm unification. Knowledge of the cytoembryological features of CMS manifestation in cereals and oilseed crops is of great importance for understanding the genetic control and practical use of this phenomenon. Utilization of wild species’ genetic resources for these purposes and applying modern techniques of the targeted genome and gene changes at the molecular, genomic, cytological and organismal levels are promising. Full article