Precursor messenger RNA (pre-mRNA) splicing is a critical post-transcriptional regulatory mechanism in gene expression. The precise splicing of pre-mRNAs is essential for plant development and responding to genetic and environmental signals. In plant sexual reproduction, gene expression regulation relies on the accurate processing of pre-mRNAs, which is fundamental for coordinating developmental programs. The alternation of generations in plants involves two key phases: gametophyte development, which produces gametes, and fertilization, which leads to the formation of a diploid sporophyte. Gametophyte and embryo development represent essential processes in plant sexual reproduction. This review focuses on summarizing and analyzing the current evidence regarding the role of pre-mRNA splicing in plant sexual reproduction, with an emphasis on its involvement in gametophyte formation and embryo development. Future challenges in understanding RNA splicing regulation in plant sexual reproduction are also discussed, particularly in modulating splicing factor levels and activities and identifying target mRNAs and non-coding RNAs regulated by these factors. This review provides crucial insights into the molecular mechanisms of plant reproductive development and offers a theoretical basis for improving plant fertility and adaptability via RNA splicing regulation.

Arabidopsis GR1 and NTRA function in pollen tube penetrating the stigma into the transmitting tract during pollination. During pollination, recognition between pollen (tube) and stigma mediates the hydration and germination of pollen, as well as the growth of the pollen tube on the stigma. Arabidopsis glutathione reductase 1 (GR1) and NADPH-dependent thioredoxin reductase A (NTRA) are involved in regulating cell redox hemostasis. Both GR1 and NTRA are expressed in pollen, but their roles in pollen germination and the growth of the pollen tube need further investigation. In this study, we performed pollination experiments and found that the Arabidopsis gr1/ + ntra/– and gr1/– ntra/ + double mutation compromised the transmission of male gametophytes. Pollen morphology and viability of the mutants did not show obvious abnormalities. Additionally, the pollen hydration and germination of the double mutants on solid pollen germination medium were comparable to those of the wild type. However, the pollen tubes with gr1 ntra double mutation were unable to penetrate the stigma and enter the transmitting tract when they grew on the surface of the stigma. Our results indicate that GR1 and NTRA play a role in regulating the interaction between the pollen tube and the stigma during pollination.

Tillering is a critical agronomic trait of wheat (Triticum aestivum L.) that determines the shoot architecture and affects grain yield. TERMINAL FLOWER 1 (TFL1), encoding a phosphatidylethanolamine-binding protein, is implicated in the transition to flowering and shoot architecture in plant development. However, the roles of TFL1 homologs is little known in wheat development. CRISPR/Cas9-mediated targeted mutagenesis was used in this study to generate a set of wheat (Fielder) mutants with single, double or triple-null tatfl1-5 alleles. The wheat tatfl1-5 mutations decreased the tiller number per plant in the vegetative growth stage and the effective tiller number per plant and spikelet number per spike at maturity in the field. RNA-seq analysis showed that the expression of the auxin signaling-related and cytokinin signaling-related genes was significantly changed in the axillary buds of tatfl1-5 mutant seedlings. The results suggested that wheat TaTFL1-5s were implicated in tiller regulation by auxin and cytokinin signaling.

Pollen longevity is critical for plant pollination and hybrid seed production, but few studies have focused on pollen longevity. In this study, we identified an Arabidopsis thaliana gene, Protein associated with lipid droplets (PALD), which is strongly expressed in pollen and critical for the regulation of pollen longevity. PALD was expressed specifically in mature pollen grains and the pollen tube, and its expression was upregulated under dry conditions. PALD encoded a lipid droplet (LD)-associated protein and its N terminus was critical for the LD localization of PALD. The number of LDs and diameter were reduced in pollen grains of the loss-of-function PALD mutants. The viability and germination of the mature pollen grains of the pald mutants were comparable with those of the wild-type, but after the pollen grains were stored under dry conditions, pollen germination and male transmission of the mutant were compromised compared with those of the wild-type. Our study suggests that PALD was required for the maintenance of LD quality in mature pollen grains and regulation of pollen longevity.

Pollen tube growth and penetration in female tissues are essential for the transfer of sperm to the embryo sac during plant pollination. Despite its importance during pollination, little is known about the mechanisms that mediate pollen tube growth in female tissues. In this study, we identified an Arabidopsis thaliana pollen/pollen tube-specific gene, SKU5-SIMILAR 13 (SKS13), which was critical for the growth of pollen tubes in the transmitting tract. The SKS13 protein was distributed throughout the cytoplasm and pollen tube walls at the apical region. In comparison with wild-type pollen tubes, those of the sks13 mutants burst more frequently when grown in vitro. Additionally, the growth of sks13 pollen tubes was retarded in the transmitting tract, thereby resulting in decreased male fertility. The accumulation of pectin and cellulose in the cell wall of sks13 pollen tubes was altered, and the content of jasmonic acid (JA) in sks13 pollen was reduced. The pollen tubes treated with an inhibitor of JA biosynthesis grew much more slowly and had an altered distribution of pectin, which is similar to the pollen tube phenotypes of the SKS13 mutation. Our results suggest that SKS13 is essential for pollen tube growth in the transmitting tract by mediating the biosynthesis of JA that modifies the components of pollen tube cell walls.

MAIN CONCLUSION:Arabidopsis AtPRP17, a homolog of yeast splicing factor gene PRP17, is expressed in siliques and embryos and functions in embryo development via regulating embryonic patterning. Yeast splicing factor PRP17/CDC40 is essential for cell growth through involvement in cell cycle regulation. Arabidopsis genome encodes a homolog of PRP17, AtPRP17; however, its function in Arabidopsis development is unknown. This study showed that AtPRP17 was highly expressed in siliques and embryos, and the protein was localized in the nucleus. The loss-of-function mutation of AtPRP17 led to shrunken seeds in Arabidopsis mature siliques. Further analysis revealed that the defective mature seeds of the mutant resulted from abnormal embryos with shriveled cotyledons, unequal cotyledons, swollen and shortened hypocotyls, or shortened radicles. During embryogenesis, mutant embryos showed delayed development and defective patterning of the apical and base domains, such as inhibited cotyledons and disorganized quiescent center cells and columella. Our results suggested that AtPRP17 functions in Arabidopsis embryo development via regulating embryonic patterning.

Plant genomes encode numerous proteins with obscure features (POFs) that lack recognized domains or motifs. However, there is little functional information for POFs even in Arabidopsis because biochemical, physiological, and genetic assay are required for the functional annotations of POFs. Here, we identified a small gene family, the endoplasmic reticulum-localized POF (ERP) family, in Arabidopsis. Phylogenetic analysis revealed that the number of ERP family members was conserved in the plant kingdom, suggesting strong selective pressure was imposed on ERP family during plant evolution. No recognizable domains were identified in the predicted ERP proteins, except for the N-terminal signal peptide. ERPs were found to be widely expressed during Arabidopsis development and showed endoplasmic reticulum localization. It was reported that ERP1 is an inositol-1,4,5-trisphosphate 5-phosphatase (5PTase), but ERP1 could not substitute for At5PTase12 in precocious pollen germination, indicating that ERP1 did not have the similar functions as At5PTase12 in inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] metabolism. Further studies are needed to dissect the functions of ERP family proteins in Arabidopsis development.

In flowering plants, pollen germination on the stigma and pollen tube growth in pistil tissues are critical for sexual plant reproduction, which are involved in the interactions between pollen/pollen tube and pistil tissues. GPI-anchored proteins (GPI-APs) are located on the external surface of the plasma membrane and function in various processes of sexual plant reproduction. The evidences suggest that GPI-APs participate in endosome machinery, Ca 2+ oscillations, the development of the transmitting tract, the maintenance of the integrity of pollen tube, the enhancement of interactions of the receptor-like kinase (RLK) and ligand, and guidance of the growth of pollen tube, and so on. In this review, we will summarize the recent progress on the roles of GPI-APs in the interactions between pollen/pollen tube and pistil tissues during pollination, such as pollen germination on the stigma, pollen tube growth in the transmitting tract, pollen tube guidance to the ovule, and pollen tube reception in the embryo sac. We will also discuss the future outlook of GPI-APs in the interactions between pollen/pollen tube and pistil tissues.

BACKGROUND:Tiller number is a factor determining panicle number and grain yield in wheat (Triticum aestivum). Auxin plays an important role in the regulation of branch production. PIN-FORMED 1 (PIN1), an auxin efflux carrier, plays a role in the regulation of tiller number in rice (Oryza sativa); however, little is known on the roles of PIN1 in wheat.RESULTS:Nine homologs of TaPIN1 genes were identified in wheat, of which TaPIN1-6 genes showed higher expression in the stem apex and young leaf in wheat, and the TaPIN1-6a protein was localized in the plasma membrane. The down-expression of TaPIN1s increased the tiller number in TaPIN1-RNA interference (TaPIN1-RNAi) transgenic wheat plants, indicating that auxin might mediate the axillary bud production. By contrast, the spikelet number, grain number per panicle, and the 1000-grain weight were decreased in the TaPIN1-RNAi transgenic wheat plants compared with those in the wild type. In summary, a reduction of TaPIN1s expression increased the tiller number and grain yield per plant of wheat.CONCLUSIONS:Phylogenetic analysis and protein structure of nine TaPIN1 proteins were analyzed, and subcellular localization of TaPIN1-6a was located in the plasma membrane. Knock-down expression of TaPIN1 genes increased the tiller number of transgenic wheat lines. Our study suggests that TaPIN1s is required for the regulation of grain yield in wheat.

Noncoding RNA (ncRNA), such as microRNA (miRNAs), long ncRNAs (lncRNAs), and circular RNAs (circRNAs) play roles in plant growth, development, and response to environmental cues via diverse manners. Splicing factors are critical for precursor messenger RNAs (pre-mRNAs) splicing and alternative splicing. Strikingly, over the past few years, an increasing number of studies demonstrated that splicing factors couple splicing to other processes, such as ncRNA biogenesis, nuclear retention, and cytoplasmic export of various RNAs, and even translation. Here, we review the current status of the noncanonical functions of splicing factors in the ncRNAs processing, retention and export of RNAs, and translation in plants.

>Fertilization produces diploid zygote as the initiation of new diploid organism by fusing two haploid gametes (sperm and egg cell). Different from animals, plants in angiosperms produce immobile sperms in pollen/pollen tube (male gametophyte). Whereas, the egg cell is located in the female gametophyte (embryo sac) that consists of two female ga-

Additional file 2. Sequences of YTHs used for the construction of phylogenetic tree.

The male–female interactions in pollination mediate pollen hydration and germination, pollen tube growth and fertilization. Reactive oxygen species (ROS) derived from both male and female tissues play regulatory roles for the communication between the pollen/pollen tube and female tissues at various stages, such as pollen hydration and germination on the stigma, pollen tube growth in the pistil and pollen tube reception in the female gametophyte. In this minireview, we primarily summarize the recent progress on the roles of ROS signaling in male–female interactions during pollination and discuss several ROS-regulated downstream signaling pathways for these interactions. Furthermore, several ROS-involved downstream pathways are outlined, such as Ca2+ signaling, cell wall cytomechanics, the redox modification of CRP, and cell PCD. At the end, we address the roles of ROS in pollen tube guidance and fertilization as future questions that merit study.

Background N6-Methyladenosine (m6A) is the most widespread RNA modification that plays roles in the regulation of genes and genome stability. YT521-B homology (YTH) domain-containing RNA-binding proteins are important RNA binding proteins that affect the fate of m6A-containing RNA by binding m6A. Little is known about the YTH genes in common wheat ( Triticum aestivum L.), one of the most important crops for humans. Results A total of 39 TaYTH genes were identified in common wheat, which are comprised of 13 homologous triads, and could be mapped in 18 out of the 21 chromosomes. A phylogenetic analysis revealed that the TaYTHs could be divided into two groups: YTHDF (TaDF) and YTHDC (TaDC). The TaYTHs in the same group share similar motif distributions and domain organizations, which indicates functional similarity between the closely related TaYTHs. The TaDF proteins share only one domain, which is the YTH domain. In contrast, the TaDCs possess three C3H1-type zinc finger repeats at their N-termini in addition to their central YTH domain. In TaDFs, the predicated aromatic cage pocket that binds the methylysine residue of m6A is composed of tryptophan, tryptophan, and tryptophan (WWW). In contrast, the aromatic cage pocket in the TaDCs is composed of tryptophan, tryptophan, and tyrosine (WWY). In addition to the general aspartic acid or asparagine residue used to form a hydrogen bond with N 1 of m6A, histidine might be utilized in some TaDFb proteins. An analysis of the expression using both online RNA-Seq data and quantitative real-time PCR verification revealed that the TaDFa and TaDFb genes are highly expressed in various tissues/organs compared with that of TaDFcs and TaDCs . In addition, the expression of the TaYTH genes is changed in response to various abiotic stresses. Conclusions In this study, we identified 39 TaYTH genes from common wheat. The phylogenetic structure, chromosome distribution, and patterns of expression of these genes and their protein structures were analyzed. Our results provide a foundation for the functional analysis of TaYTH s in the future.

植物解剖学实验作为植物学课程教学的重要组成部分,不仅能够巩固植物学理论知识,锻炼学生的观察和操作能力,也有利于培养学生的实践创新能力和严谨的科学态度.重点从学生课堂表现的评价、实验报告的绘制和考核形式等方面探讨了植物解剖学实验教学的改革措施,为提高教学质量提供指导.

Additional file 6. Sequences of animal YTHDC1s and plant YTHDCs.

植物学野外实习是植物学课程教学的重要环节,不仅有助于学生学习物种分类的基本原理并掌握标本采集制作方法,还能巩固植物学理论知识.为提高教学质量,重点从掌握理论知识,加强现代技术应用,合理推进教学进程和优化考核方式等方面探讨了野外实习教学模式的改进措施,为提升野外实习效果提供指导.

The inflorescence architecture of grass crops affects the number of kernels and final grain yield. Great progress has been made in genetic analysis of rice inflorescence development in the past decades. However, the advances in wheat largely lag behind those in rice due to the repetitive and polyploid genomes of wheat. In view of the similar branching patterns and developmental characteristics between rice and wheat, the studies on inflorescence architecture in rice will facilitate related studies in wheat in the future. Here, we review the developmental regulation of inflorescences in rice and wheat and highlight several pathways that potentially regulate the inflorescence architecture of wheat.

植物学是农业院校生物科学类专业及植物生产类专业的一门重要的专业基础课.植物学实验是植物学课程体系的一部分,是课堂教学内容的延伸,是农业院校重要的实践教学课程.本研究从合并课堂学时、丰富实验内容、调整实验课成绩考核办法等方面入手,对植物学实验课程进行了改革和探索.实践证明,教学改革调动了学生学习的积极性和主动性,学生实验课成绩明显提高,锻炼了学生的实验技能及科研创新能力,加深了植物学课堂理论知识学习效果.

凝胶迁移实验(EMSA-Electrophoretic Mobility Shift Assay)是一种研究蛋白质与核酸相互作用的常用实验技术.在凝胶迁移率实验的教学工作中,由于受实验材料的影响,尤其是EMSA探针浓度的变化,对实验结果的影响很大.为进一步提高实验教学效果,将探针浓度对实验结果的影响进行了比较.通过设置一系列浓度梯度实验,发现采用浓度为5nmol的探针实验效果最好,改进后的实验效果更加明显.