China has a high dependence on soybean imports, yield increase at a faster rate is an urgent problem that need to be solved at present. The application of heterosis is one of the effective ways to significantly increase crop yield. In recent years, the development of an intelligent male sterility system based on recessive nuclear sterile genes has provided a potential solution for rapidly harnessing the heterosis in soybean. However, research on male sterility genes in soybean has been lagged behind. Based on transcriptome data of soybean floral organs in our research group, a soybean stamen-preferentially expressed gene GmFLA22a was identified. It encodes a fasciclin-like arabinogalactan protein with the FAS1 domain, and subcellular localization studies revealed that it may play roles in the endoplasmic reticulum. Take advantage of the gene editing technology, the Gmfla22a mutant was generated in this study. However, there was a significant reduction in the seed-setting rate in the mutant plants at the reproductive growth stage. The pollen viability and germination rate of Gmfla22a mutant plants showed no apparent abnormalities. Histological staining demonstrated that the release of pollen grains in the mutant plants was delayed and incomplete, which may due to the locule wall thickening in the anther development. This could be the reason of the reduced seed-setting rate in Gmfla22a mutants. In summary, our study has preliminarily revealed that GmFLA22a may be involved in regulating soybean male fertility. It provides crucial genetic materials for further uncovering its molecular function and gene resources and theoretical basis for the utilization of heterosis in soybean.
我国大豆对外依赖度高，加速提高大豆产量是目前亟需解决的问题。利用杂种优势是大幅提高作物产量的有效途径之一，近年来基于隐性核不育基因开发的智能雄性不育系统，为快速利用大豆杂种优势提供了可能。但是，大豆雄性不育基因研究相对滞后。本研究基于课题组大豆花器官转录组数据，筛选到在大豆早期花药中优势表达基因GmFLA22a，编码含有FAS1结构域的成束状阿拉伯半乳糖蛋白，亚细胞定位表明其可能在内质网中发挥功能。利用基因编辑技术获得Gmfla22a突变体，突变体植株在营养生长阶段与对照组相比没有明显差异，但在生殖生长阶段表现为结实率显著降低。Gmfla22a突变体花粉活力和花粉萌发率均无明显异常，组织切片并染色观察发现，突变体植株花药室壁增厚，花粉粒释放延迟、不完全，这可能是导致Gmfla22a结实率降低的原因。综上，本研究初步揭示GmFLA22a可能参与调控大豆雄性育性，为深入揭示其分子功能提供重要遗传材料，同时为大豆杂种优势利用提供基因资源和理论依据。.

Cytoplasmic male sterile system (CMS) is one of the important methods for the utilization of heterosisin Brassica napus. The involvement of long non-coding RNAs (lncRNAs) in anther and pollen development in B.napus has been recognized, but there is little data on the involvement of lncRNAs in pollen abortion in different types of rapeseed CMS. The present study compared the cytological, physiological and biochemical characteristics of Nsa CMS (1258A) and Pol CMS (P5A) during pollen abortion, and high-throughput sequencing of flower buds of different sizes before and after pollen abortion. The results showed that insufficient energy supply was an important physiological basis for 1258A and P5A pollen abortion, and 1258A had excessive ROS (reactive oxygen species) accumulation in the stage of pollen abortion. Functional analysis showed that Starch and sucrose metabolism and Sulfur metabolism were significantly enriched before and after pollen abortion in 1258A and P5A, and a large number of genes were down-regulated. In 1258A, 227 lncRNAs had cis-targeting regulation, and 240 cis-target genes of the lncRNAs were identified. In P5A, 116 lncRNAs had cis-targeting regulation, and 101 cis-target genes of the lncRNAs were identified. There were five lncRNAs cis-target genes in 1258A and P5A during pollen abortion, and LOC106445716 encodes β-D-glucopyranosyl abscisate β-glucosidase and could regulate pollen abortion. Taken together, this study, provides a new perspective for lncRNAs to participate in the regulation of Nsa CMS and Pol CMS pollen abortion.

BACKGROUND: Chinese cabbage is one of the most widely grown leafy vegetables in China. Cytoplasmic male sterility (CMS) is a maternally inherited trait that produces abnormal pollen during anther development, which is commonly seen in cruciferous vegetables. However, the molecular mechanism of Chinese cabbage CMS is not clear. In this study, the metabolome and hormone profiles of Chinese cabbage male sterile line (CCR20000) and sterile maintainer line (CCR20001) were analyzed in flower buds during normal stamen development and abnormal stamen development, respectively.
RESULTS: A total of 556 metabolites were detected based on UPLC-MS/MS detection platform and database search, and the changes of hormones such as auxin, cytokinins, abscisic acid, jasmonates, salicylic acid, gibberellin acid and ethylene were analyzed. The results showed that compared with the male fertile line (MF), the male sterile line (MS) significantly decreased the content of flavonoids and phenolamides metabolites in the stamen dysplasia stage, accompanied by a large accumulation of glucosinolate metabolites. Meanwhile, the contents of GA9, GA20, IBA, tZ and other hormones in MS were significantly lower than those in MF strains. Further, by comparing the metabolome changes of MF and MS during stamen dysplasia, it was found that flavonoid metabolites and amino acid metabolites were distinctly different.
CONCLUSIONS: These results suggest that flavonoids, phenolamides and glucosinolate metabolites may be closely related to the sterility of MS strains. This study provides an effective basis for further research on the molecular mechanism of CMS in Chinese cabbage.

BACKGROUND: Cytoplasmic male sterility (CMS), which naturally exists in higher plants, is a useful mechanism for analyzing nuclear and mitochondrial genome functions and identifying the role of mitochondrial genes in the plant growth and development. Polima (pol) CMS is the most universally valued male sterility type in oil-seed rape. Previous studies have described the pol CMS restorer gene Rfp and the sterility-inducing gene orf224 in oil-seed rape, located in mitochondria. However, the mechanism of fertility restoration and infertility remains unknown. Moreover, it is still unknown how the fecundity restorer gene interferes with the sterility gene, provokes the sterility gene to lose its function, and leads to fertility restoration.
RESULTS: In this study, we used multi-omics joint analysis to discover candidate genes that interact with the sterility gene orf224 and the restorer gene Rfp of pol CMS to provide theoretical support for the occurrence and restoration mechanisms of sterility. Via multi-omics analysis, we screened 24 differential genes encoding proteins related to RNA editing, respiratory electron transport chain, anther development, energy transport, tapetum development, and oxidative phosphorylation. Using a yeast two-hybrid assay, we obtained a total of seven Rfp interaction proteins, with orf224 protein covering five interaction proteins.
CONCLUSIONS: We propose that Rfp and its interacting protein cleave the transcript of atp6/orf224, causing the infertility gene to lose its function and restore fertility. When Rfp is not cleaved, orf224 poisons the tapetum cells and anther development-related proteins, resulting in pol CMS mitochondrial dysfunction and male infertility. The data from the joint analysis of multiple omics provided information on pol CMS\'s potential molecular mechanism and will help breed B. napus hybrids.

Double pollen fertility neutral genes, San and Sbn, can control pollen sterility in intersubspecific (indica × japonica) rice hybrids, which has excellent potential to increase rice yield. Previous studies showed that polyploidy could increase the interaction of three pollen sterility loci, i.e. Sa, Sb and Sc, which cause pollen sterility in autotetraploid rice hybrids, and hybrid fertility could be improved by double neutral genes, San and Sbn, in autotetraploid rice hybrids. We compared cytological and transcriptome data between autotetraploid and diploid rice hybrid during meiosis and single microspore stages to understand the molecular mechanism of neutral genes for overcoming pollen sterility in autotetraploid rice hybrids, which harbored double neutral genes. Cytological results revealed that the double neutral genes resulted in higher pollen fertility (76.74%) and lower chromosomal abnormalities in autotetraploid hybrid than in parents during metaphase I, metaphase II, anaphase I and anaphase II. Moreover, autotetraploid rice hybrid displayed stronger heterosis than a diploid hybrid. Compared with diploid rice hybrid, a total of 904 and 68 differently expressed genes (DEGs) were identified explicitly in autotetraploid hybrid at meiosis and single microspore stages, respectively. Of these, 133 and 41 genes were detected in higher-parent dominance and transgressive up-regulation dominance, respectively, which were considered autotetraploid potential heterosis genes, including a meiosis-related gene (Os01g0917500, MSP1) and two meiosis specific-genes (Os07g0624900 and Os04g0208600). Gene Ontology (GO) and Kyoto Encyclopedia of Gene and Genomes pathway (KEGG) analysis revealed that DEGs significantly enriched in amino acid metabolism and photosynthesis metabolism. These results indicated that meiosis-specific and meiosis-related genes, and amino acids and photosynthesis metabolism-related genes contribute to higher yield and pollen fertility in autotetraploid rice hybrid. This study provides a theoretical basis for molecular mechanisms of heterosis in autotetraploid rice harboring double neutral genes for pollen fertility.

Stigma exsertion and panicle enclosure of male sterile lines are two key determinants of outcrossing in hybrid rice seed production. Based on 43,394 single nucleotide polymorphism markers, 217 cytoplasmic male sterile lines were assigned into two subpopulations and a mixed-group where the linkage disequilibrium decay distances varied from 975 to 2,690 kb. Genome-wide association studies (GWAS) were performed for stigma exsertion rate (SE), panicle enclosure rate (PE) and seed-setting rate (SSR). A total of 154 significant association signals (P < 0.001) were identified. They were situated in 27 quantitative trait loci (QTLs), including 11 for SE, 6 for PE, and 10 for SSR. It was shown that six of the ten QTLs for SSR were tightly linked to QTLs for SE or/and PE with the expected allelic direction. These QTL clusters could be targeted to improve the outcrossing of female parents in hybrid rice breeding. Our study also indicates that GWAS-base QTL mapping can complement and enhance previous QTL information for understanding the genetic relationship between outcrossing and its related traits.

OBJECTIVE: Many aquatic species with stylar polymorphisms have the capacity for clonal and sexual reproduction and are sensitive to the balance of the two reproductive modes when there are a limited number of mating morphs within a population. This study asked how the clonal and sexual reproductive modes perform in populations that contain only a single morph and where fitness gain through sexual reproduction is rare. In clonal aquatic Nymphoides montana, polymorphic populations normally contain two mating morphs in equal frequencies. Populations are sexually fertile and appear to be maintained by pollen transfer between the two partners. However, in a monomorphic population of N. montana where mating opportunities are unavailable, female and male function is impaired and clonality maintains the population. Here, the consequences of intraspecific variation in sexuality were explored between monomorphic and polymorphic N. montana populations in eastern Australia.
METHODS: Comparative measurements of male and female fertility, total dry mass and genotypic diversity using ISSR markers were made between populations with variable sexuality.
CONCLUSIONS: Very few seeds were produced in the monomorphic population under natural and glasshouse conditions due to dysfunctional pollen and ovules. Stigma-anther separation was minimal in the monomorphic population, which may be a consequence of the relaxed selective pressures that regulate the maintenance of sexual function. However, clonal reproduction was favoured at the expense of sexual reproduction in the monomorphic population; this may facilitate the establishment of sterility throughout the population via resource reallocation or pleiotropic effects. The ISSR results showed that the monomorphic population was one large, single genotype, unlike the multi-genotypic fertile polymorphic populations. Evolutionary loss of sex in a clonal population in which a mating morph is absent was evident; under these conditions clonal growth may assure reproduction and expand the population via spreading stolons.

Sterile and reproductive tissues of five brown algae (Sargassum pallidum, Silvetia babingtonii, Fucus evanescens, Saccharina japonica, and Alaria ochotensis) from Russian Far East seas were compared for the content and monosaccharide composition of fucoidans as well as the content of laminarans and alginic acids. It was proved that reproduction has an apparent effect on fucoidan content and its monosaccharide composition. Fucoidan content in fertile tissues was shown to be 1.3-1.5 times as high as in sterile ones. Based on the present and previously reported data, we believe that fucoidan accumulation during the development of reproductive structure is a general trend for brown seaweeds. Reproduction also caused changes in the monosaccharide composition. As a result, fertile plants synthesized fucoidan with less heterogeneous monosaccharide composition in comparison with sterile ones. Structural changes of this polysaccharide are species-specific and perhaps depend on the type of the synthesized polysaccharide. The fertile plants of S. babingtonii yielded the highest fucoidan content [25% dry weight (dw)] among the tested species, whereas the maximum alginic acid content was found for the sterile tissues of S. japonica-up to 43% dw. There was no general trend in alginic acid content variation during sporulation. The alginic acid content was much higher in the sterile tissues of S. japonica in comparison with the fertile ones. On the contrary, the fertile tissues of A. ochotensis contained more alginic acid than the sterile ones.

OBJECTIVE: To have a better utilization of male sterile lines in heterozygotic breeding of Platycodon grandiflorum and provide theoretical basis for Platycodon grandiflorum hyboridization.
METHODS: The pollen viability was detected by the means of aceto carmine dyeing, and the correlation analysis between climate factors of each anther development stage and pollen viability was estimated by Pearson coefficients.
RESULTS: Pollen viability variation range of male-sterile line GP1BC1-12 was 0% - 27%. That of male-sterile line GP12BC4-10 and chifeng germplasm was respectively 1.3% - 17.9% and 75.9% - 98.5%. Further linear regression analysis between climate factors of each anther development stage and pollen viability indicated that the degree of sensitivity varied with different germplasm of Platycodon grandiflorum. Among three germplasm, male sterile line GP12BC4-10 was the most stable one to the climate factors, and the male-sterile line GP1BC1-12 was the most sensitive one.
CONCLUSIONS: Temperature and solar irradiation are the most important climate factors to affect pollen viability in Platycodon grandflorum, and microspore mother cells stage (MMC) is its sensetive stage.

Plant male sterility is a kind of resource of heterosis, which has important value in production. It may be derived from natural mutations, artificial mutations, distant hybridizations, and now through cell engineering and genetic engineering. This paper reviews the progress of strategies in production of plant male sterile lines and their corresponding fertile lines via genetic engineering approach. All strategies can be grouped into \"single component strategy\" and \"two-component strategy\". \"Single component strategy\" produces conditional (reversible) male sterile line, whose fertility can be switched under given condition. Conditional male sterile line has two roles, which are CMS and maintainer line for breeding in practice; \"two-component strategy\" takes advantage of gene interaction and parental hybridization to generate male sterile line. Otherwise, it develops sterile line and restorer line respectively for three-line hybrid system for seed production through gene interaction. This paper discusses the advantages and disadvantages of gene engineering approaches of \"single component strategy\" and \"two-component strategy\" for developing male sterile line and corresponding restorer line, as well as the current status and perspective of these approaches in practice.