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Polyploidy and life-strategy transitions between annuality and perenniality often occur in flowering plants. However, the evolutionary propensities of polyploids and the genetic bases of such transitions remain elusive. We assembled chromosome-level genomes of representative perennial species across the genus Glycine including five diploids and a young allopolyploid, and constructed a Glycine super-pangenome framework by integrating 26 annual soybean genomes. These perennial diploids exhibit greater genome stability and possess fewer centromere repeats than the annuals. Biased subgenomic fractionation occurred in the allopolyploid, primarily by accumulation of small deletions in gene clusters through illegitimate recombination, which was associated with pre-existing local subgenomic differentiation. Two genes annotated to modulate vegetative-reproductive phase transition and lateral shoot outgrowth were postulated as candidates underlying the perenniality-annuality transition. Our study provides insights into polyploid genome evolution and lays a foundation for unleashing genetic potential from the perennial gene pool for soybean improvement.

Background The coronavirus disease 2019 (COVID-19) outbreak has had a widespread and profound impact on people’s mental health. The factors associated with mental symptoms among men diagnosed with infertility, a disease closely related to psychological conditions, remain unclear. The aim of this study is to investigate the risk factors associated with mental symptoms among infertile Chinese men during the pandemic. Results A total of 4,098 eligible participants were recruited in this cross-sectional, nationwide study, including 2,034 (49.6%) with primary infertility and 2,064 (50.4%) with secondary infertility. The prevalence of mental health conditions was 36.3%, 39.6%, and 6.7% for anxiety, depression, and post-pandemic stress, respectively. Sexual dysfunction is associated with a higher risk with adjusted odds ratios (ORs) of 1.40 for anxiety, 1.38 for depression, and 2.32 for stress. Men receiving infertility drug therapy displayed a higher risk for anxiety (adjusted OR, 1.31) and depression (adjusted OR, 1.28) symptoms, while those receiving intrauterine insemination had a lower risk of anxiety (adjusted OR, 0.56) and depression (adjusted OR, 0.55) symptoms. Conclusion The COVID-19 pandemic has had a significant psychological impact on infertile men. Several psychologically vulnerable populations were identified, including individuals with sexual dysfunction, respondents receiving infertility drug therapy, and those experiencing control measures for COVID-19. The findings provide a comprehensive profile of the mental health status of infertile Chinese men during the COVID-19 outbreak and provide potential psychological intervention strategies.

Maize height is determined by the number of nodes and the length of internodes. Node number is driven by intercalary meristem formation and internode length by intercalary cell elongation, respectively. However, mechanisms regulating establishment of nodes and internode growth are unclear. We screened EMS-induced maize mutants and identified a dwarf mutant zm66, linked to a single base change in TERMINAL EAR 1 (ZmTE1). Detailed phenotypic analysis revealed that zm66 (zmte1-2) has shorter internodes and increased node numbers, caused by decreased cell elongation and disordered intercalary meristem formation, respectively. Transcriptome analysis showed that auxin signalling genes are also dysregulated in zmte1-2, as are cell elongation and cell cycle-related genes. This argues that ZmTE1 regulates auxin signalling, cell division, and cell elongation. We found that the ZmWEE1 kinase phosphorylates ZmTE1, thus confining it to the nucleus and probably reducing cell division. In contrast, the ZmPP2Ac-2 phosphatase promotes dephosphorylation and cytoplasmic localization of ZmTE1, as well as cell division. Taken together, ZmTE1, a key regulator of plant height, is responsible for maintaining organized formation of internode meristems and rapid cell elongation. ZmWEE1 and ZmPP2Ac-2 might balance ZmTE1 activity, controlling cell division and elongation to maintain normal maize growth.

Tillering contributes greatly to grain yield in wheat. Investigating the mechanisms of tillering provides a theoretical foundation and genetic resources for the molecular breeding of wheat. The regulation of tillering is a complex molecular process that involves a multitude of factors. Little is known about the molecular mechanisms in the wheat genome, although progress has been made in rice. Here we review the developmental characteristics of tillers and summarize current knowledge of the roles of endogenous and environmental factors in wheat tillering. We propose directions for future studies and advanced technologies to be used for gene identification and functional studies.

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.

Spike architecture largely affects grain number embraced, which is an important trait to optimize during wheat breeding process. In this study, we incorporated multi-omic data and investigated the genetic regulation of wheat spike development. We generated transcriptome and epigenome profiles of shoot apex at eight developmental stages and observed that chromatin accessibility and H3K27me3 abundance coordinated with transcriptome alteration for flowering transition. A core transcriptional regulatory network (TRN) that drove the formation of the wheat spike was constructed. Integration of the TRN and genome-wide association analysis (GWAS) led to the identification of 227 transcription factors (TFs) with both known (42) and unknown (185) functions. Multi-layer regulatory module among TaSPL6, TaMADS34 and TaMADS15 identified by TRN was validated experimentally. Of the 85 novel TFs with homozygous mutant lines in TILLING library, 38 showed altered spike architecture or flowering time, including bHLH, MYB, and WRKY. Furthermore, we demonstrated that TaMYB4-A regulates fertile spikelet number likely via regulating hormones homeostasis and signaling, and is downstream of, and repressed by WFZP. The elite allele of TaMYB4-A, with a C-SNP at the WFZP binding site, was selected for balancing spikelet number and fertility during breeding process in China. Collectively, our findings provide high-confidence novel regulators and an efficient strategy for studying the genetic basis of wheat spike development for practical breeding applications.

ObjectiveThe objectives of this study were to compare the efficacy, advantages, and disadvantages of insertable ureteral reimplantation (UC group) and ureteral end-to-side anastomosis (UU group) in the treatment of duplicated kidney and summarize the clinical experience in its diagnosis and treatment.MethodsThe current retrospective study enrolled 20 cases with duplicated kidney in Anhui Provincial Children's Hospital from April 2016 to June 2021, including 11 in the UC group and 9 in the UU group. There were 8 boys and 12 girls, with 12 on the left side and 8 on the right side. Meanwhile, there were three cases with urinary tract infection and nine with urinary incontinence. The rest of them were found by B ultrasound during physical examination. The median age of these patients was 33.5 months. Later, preoperative and postoperative renal pelvis separation, ureteral dilation, operation time, and drainage tube indwelling time were compared between the two groups.ResultsThere were statistically significant differences in operation time (282 ± 50.55 vs. 176 ± 61.92, P = 0.03), drainage time (9.36 ± 5.00 vs. 5.33 ± 1.22, P = 0.02), and hospital stay (22.18 ± 5.40 vs. 14.78 ± 5.33, P = 0.007) between the two groups. In addition, the degree of hydronephrosis (UC: 1.86 ± 0.93 vs. 1.08 ± 0.77, P = 0.00; UU: 1.8 ± 0.95 vs. 0.89 ± 0.60, P = 0.02) and ureteral dilatation (UC: 1.57 ± 0.30 vs. 0.72 ± 0.22, P = 0.00; UU: 1.47 ± 0.50 vs. 0.88 ± 0.22, P = 0.001) were statistically different between the two groups before and after surgery.ConclusionCompared with the UC method, the UU method has the advantages of less trauma, faster recovery, and fewer complications. Double J tube or ureter stent placement is beneficial for finding and protecting the lower ureter intraoperatively, without increasing the difficulty in operation, which can also prevent anastomosis or ureteral orifice stenosis.

Seed size is a major factor determining crop yields that is controlled through the coordinated development of maternal and zygotic tissues. Here, we identified Arabidopsis MATERNAL EFFECT EMBRYO ARREST45 (MEE45) as a B3 transcription factor that controls cell proliferation and maternally regulates seed size through its transcriptional activation of AINTEGUMENTA (ANT) and its downstream control of auxin biosynthesis in the ovule integument. After characterizing reduced seed and organ size phenotypes in mee45 mutants and finding that overexpression of MEE45 causes oversized seeds, we discovered that the MEE45 protein can bind to the promoter region of the ANT locus and positively regulate its transcription. ANT in-turn activates the expression of auxin biosynthetic genes (e.g. YUCCA4) in the ovule integument. Our results thus illustrate mechanisms underlying maternal tissue-mediated regulation of seed size and suggest that MEE45 and its downstream components can be harnessed to develop higher-yielding crop varieties.

Background Pentatricopeptide repeat (PPR) proteins compose a large protein family whose members are involved in both RNA processing in organelles and plant growth. Previous reports have shown that E-subgroup PPR proteins are involved in RNA editing. However, the additional functions and roles of the E-subgroup PPR proteins are unknown. Results In this study, we developed and identified a new maize kernel mutant with arrested embryo and endosperm development, i.e., defective kernel (dek) 55 (dek55). Genetic and molecular evidence suggested that the defective kernels resulted from a mononucleotide alteration (C to T) at + 449 bp within the open reading frame (ORF) of Zm00001d014471 (hereafter referred to as DEK55). DEK55 encodes an E-subgroup PPR protein within the mitochondria. Molecular analyses showed that the editing percentage of 24 RNA editing sites decreased and that of seven RNA editing sites increased in dek55 kernels, the sites of which were distributed across 14 mitochondrial gene transcripts. Moreover, the splicing efficiency of nad1 introns 1 and 4 and nad4 intron 1 significantly decreased in dek55 compared with the wild type (WT). These results indicate that DEK55 plays a crucial role in RNA editing at multiple sites as well as in the splicing of nad1 and nad4 introns. Mutation in the DEK55 gene led to the dysfunction of mitochondrial complex I. Moreover, yeast two-hybrid assays showed that DEK55 interacts with two multiple organellar RNA-editing factors (MORFs), i.e., ZmMORF1 (Zm00001d049043) and ZmMORF8 (Zm00001d048291). Conclusions Our results demonstrated that a mutation in the DEK55 gene affects the mitochondrial function essential for maize kernel development. Our results also provide novel insight into the molecular functions of E-subgroup PPR proteins involved in plant organellar RNA processing.

Cold stress is a major environmental factor affecting the growth, development, and productivity of various crop species. With the current trajectory of global climate change, low temperatures are becoming more frequent and can significantly decrease crop yield. Wheat (Triticum aestivum L.) is the first crop to be domesticated and is the most popular cereal crop in the world. Due to a lack of systematic research on cold response pathways and gene regulatory networks, the underlying molecular mechanisms of cold signal transduction in wheat are poorly understood. This study reviews recent progress in wheat, including the ICE-CBF-COR signaling pathway in cold stress and the effects of cold stress on hormonal pathways, reactive oxygen species (ROS), and epigenetic regulation. This review also highlights outstanding issues that are crucial for understanding the interactions between wheat and low-temperature conditions.

ARF4-regulated shoot regeneration through competing with ARF5 for the interaction with IAA12. Plant possess the ability to regenerate shoot meristem and subsequent the whole individual. This process is the foundation for in vitro propagation and genetic engineering and provides a system for studying fundamental biological questions, such as hormonal signaling. Auxin response factor (ARF) family transcription factors are critical components of auxin signaling pathway that regulate the transcription of target genes. To date, the mechanisms underlying the functions of class-B ARFs which act as transcription repressors remains unclear. In this study, we found that ARF4, the transcriptional repressor, was involved in regulating shoot regeneration. ARF4 interacted with auxin/Indole-3-Acetic-Acid12 (IAA12). The expression signals of ARF4 displayed a dynamic pattern similar with those of ARF5 and IAA12 during shoot meristem formation. Enhanced expression of IAA12 compromised the shoot regeneration capacity. Induced expression of ARF4 complemented the regeneration phenotype of IAA12-overexpression but did not rescued the defects in the arf5 mutant, mp-S319. Further analysis revealed that ARF4 competed with ARF5 for the interaction with IAA12. The results indicate that ARF4-regulated shoot regeneration through cooperating with ARF5 and IAA12. Our findings provided new information for deciphering the function of class-B ARFs.

Cytokinins are a class of phytohormone that participate in the regulation of the plant growth, development, and stress response. In this review, the potential regulating mechanism during plant growth and stress response are discussed. Cytokinins are a class of phytohormone that participate in the regulation of plant growth, physiological activities, and yield. Cytokinins also play a key role in response to abiotic stresses, such as drought, salt and high or low temperature. Through the signal transduction pathway, cytokinins interact with various transcription factors via a series of phosphorylation cascades to regulate cytokinin-target gene expression. In this review, we systematically summarize the biosynthesis and metabolism of cytokinins, cytokinin signaling, and associated gene regulation, and highlight the function of cytokinins during plant development and resistance to abiotic stress. We also focus on the importance of crosstalk between cytokinins and other classes of phytohormones, including auxin, ethylene, strigolactone, and gibberellin. Our aim is to provide a comprehensive overview of recent findings on the mechanisms by which cytokinins act as central regulators of plant development and stress reactions, and highlight topics for future research.

N6-methyladenosine (m6A) is the most common type of eukaryotic mRNA modification. It plays an important role in regulating plant growth and development and stress resistance. m6A modification influences nearly all aspects of RNA metabolism and functionality and has great potential for improving crop quality. However, changing m6A modification levels as a whole may have unpredictable effects, making it impossible to accurately predict the effect of specific m6A modifications on RNA. In this opinion article, the main challenges and possible solutions for exploring m6A modification functions in plant systems are discussed. An m6A editing platform that uses new high-throughput methods to identify m6A modification at single-base resolution, and genome editing for selective editing of specific m6A sites for crop improvement is proposed.

Significance Pluripotent stem cells are critical in both animal and plant development. Unlike higher animals, plants have unique postembryonic development, which continuously produce organs depending on shoot and root meristems. In the shoot meristem, division of the stem cells in the outermost layers provides the cells for all shoot structures. How those meristem cells are tightly controlled attracted intense studies. Genetic and molecular analyses in Arabidopsis have identified the key transcription factors WUSCHEL (WUS) and SHOOTMERISTEMLESS (STM) as the major regulators of pluripotency in the shoot meristem. Here, the results provide solid evidence showing how those two pluripotency factors WUS and STM coordinate to control shoot meristem cells strictly in plants., In the shoot meristem, both WUSCHEL (WUS) and SHOOT MERISTEMLESS (STM), two transcription factors with overlapping spatiotemporal expression patterns, are essential for maintaining stem cells in an undifferentiated state. Despite their importance, it remains unclear how these two pathways are integrated to coordinate stem cell development. Here, we show that the WUS and STM pathways in Arabidopsis thaliana converge through direct interaction between the WUS and STM proteins. STM binds to the promoter of CLAVATA3 (CLV3) and enhances the binding of WUS to the same promoter through the WUS–STM interaction. Both the heterodimerization and simultaneous binding of WUS and STM at two sites on the CLV3 promoter are required to regulate CLV3 expression, which in turn maintains a constant number of stem cells. Furthermore, the expression of STM depends on WUS, and this WUS-activated STM expression enhances the WUS-mediated stem cell activity. Our data provide a framework for understanding how spatial expression patterns within the shoot meristem are translated into regulatory units of stem cell homeostasis.

How somatic cells develop into a whole plant is a central question in plant developmental biology. This powerful ability of plant cells is recognized as their totipotency. Somatic embryogenesis is an excellent example and a good research system for studying plant cell totipotency. However, very little is known about the molecular basis of cell reprogramming from somatic cells to totipotent cells in this process. During somatic embryogenesis from immature zygotic embryos in Arabidopsis, exogenous auxin treatment is required for embryonic callus formation, but removal of exogenous auxin inducing endogenous auxin biosynthesis is essential for somatic embryo (SE) induction. Ectopic expression of specific transcription factor genes, such as “LAFL” and BABY BOOM (BBM), can induce SEs without exogenous growth regulators. Somatic embryogenesis can also be triggered by stress, as well as by disruption of chromatin remodeling, including PRC2-mediated histone methylation, histone deacetylation, and PKL-related chromatin remodeling. It is evident that embryonic identity genes are required and endogenous auxin plays a central role for cell reprogramming during the induction of SEs. Thus, we focus on reviewing the regulation of cell reprogramming for somatic embryogenesis by auxin.

Plant cells have a powerful capacity in their propagation to adapt to environmental change, given that a single plant cell can give rise to a whole plant via somatic embryogenesis without the need for fertilization. The reprogramming of somatic cells into totipotent cells is a critical step in somatic embryogenesis. This process can be induced by stimuli such as plant hormones, transcriptional regulators and stress. Here, we review current knowledge on how the identity of totipotent cells is determined and the stimuli required for reprogramming of somatic cells into totipotent cells. We highlight key molecular regulators and associated networks that control cell fate transition from somatic to totipotent cells. Finally, we pose several outstanding questions that should be addressed to enhance our understanding of the mechanisms underlying plant cell totipotency.

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 N1 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 TaYTHs in the future.

AGC1-4 kinase plays a crucial role in the regulation of seeds by mediating cell proliferation and embryo development in Arabidopsis. Seed size is a crucial factor to influence final seed yield in plants. However, the molecular mechanisms that set final seed size still need to be investigated. Here, we identified a novel AGC protein kinase AGC1-4, which encodes a serine-threonine kinase, belongs to the AGC VIIIa subfamily. The seeds of agc1-4 mutant were significantly larger than that in the wild type. Overexpression of the AGC1-4 gene reduced seed size. Regulation of AGC1-4 seed size is dependent on embryonic cell number. To further determine AGC1-4 functions in seed size, we analyzed AGC1-4 phosphoproteins using label-free quantitative phosphoproteomics coupled to the transcriptome of agc1-4 using RNA sequencing (RNA-seq). The RNA-seq analysis showed 1611 differentially expressed genes (DEGs), which cover a wide range of functions, such as cell cycle and embryo development. The 262 unique phosphoproteins were detected by phosphoproteomics analysis. The differentially phosphorylated proteins were involved in cell cycle and post-embryo development. Overlay of the RNA-seq and phosphoproteomics results demonstrated AGC1-4 as an important factor that influences seed size by mediating cell proliferation and embryo development. The results in this study provide novel data on the serine-threonine kinase AGC1-4 mediating seed size in Arabidopsis.

Somatic cells of higher plants possess the remarkable ability to regenerate new individuals via reestablishing apical meristems. Reconstitution of shoot meristem is the vital process and is required for application of plant biotechnology. Under

To observe the clinical effect of prostatic artery embolization (PAE) in the treatment of high-risk patients with BPH.Nine high-risk patients with BPH underwent PAE in the Third Affiliated Hospital of Anhui Medical University from January 2016 to June 2018. We followed up the patients and obtained their IPSS, quality of life score (QOL), postvoid residual urine volume (PVR), maximum urinary flow rate (Qmax), prostate volume (PV), hours of undisturbed sleep (HUS), Self-Rating Anxiety Scale score (SAS) and incidence of postoperative complications before and at 6, 12 and 24 months or longer after surgery, followed by comparative analysis of the parameters.Compared with baseline, IPSS, QOL, PVR, Qmax, PV, HUS and SAS were all significantly improved in the patients at 6, 12 and ≥24 months after PAE (P0.05). Only 1 case complained of mild numbness in the buttocks, which was gradually relieved after acupuncture therapy.Prostatic artery embolization is definitely effective for the treatment of high-risk patients with BPH with the bladder volume ≥200 ml, with few postoperative complications, and can be used as an effective therapeutic supplementary for improving the urination symptoms of the patients.

Objectives: The objective of the study is to investigate the feasibility and efficacy of urethroplasty with a Buck's fascia integral-covering technique (BFIC) to wrap and restore the normal anatomical structure of the penis in one-stage hypospadias surgery.Methods: One-stage surgeries for hypospadias management were performed using BFIC from January 2016 to September 2020 at four high-volume medical centers in China. The technique integrates Buck's fascia with glans wings to mobilize and wrap the urethra and restore penile anatomical relationships. The clinical data, postoperative follow-up data, and complications were recorded, and the results were analyzed.Results: A total of 1,386 patients were included in the study: 1,260 cases of primary hypospadias and 126 cases of re-operations; distal in 382 cases (27.6%), mid-shaft in 639 (46.1%), proximal in 365 (26.3%); tubularized incised plate (TIP) in 748 cases, inlay-graft in 124, onlay-graft in 49, Mathieu in 28, free-tube graft urethroplasty in 406, and 31 of hybrid procedures. One thousand one hundred forty-two patients (82.4%) were found to have penile curvature (>10°) after artificial erection and all corrected by dorsal plication/s or transection of the urethra plate (UP) simultaneously. The median followed-up time was 27 months (6–62). A total of 143 (10.3%) complications were recorded: 114 (9.0%) in the primary operations and 29 (23%) in the re-operations, 15 (3.9%) in distal hypospadias, 61 (9.5%) in mid-shaft, and 67 (18.4%) in proximal. The complication rate in UP preservation and transection was 10.1 and 10.8%, respectively. Of all case complications, there were 73 (5.2%) of fistula, 10 (0.6%) of dehiscence, 22 (1.6%) of meatal stenosis, 21 (1.5%) of stricture, 6 (0.7%) of diverticulum, and resident curvature in 11 cases (1.2%). The overall complication rate in TIP and free-tube procedure was 9.8 and 9.9%, respectively, and fistula occurred in primary TIP of 33 cases (4.9%).Conclusions: Buck's fascia with the glans can be used as an integral covering technique in one-stage distal to proximal hypospadias and primary or re-operative hypospadias repair. It is safe, feasible, and effective for the repair of hypospadias.

Summary Tillering is a significant agronomic trait in wheat which shapes plant architecture and yield. Strigolactones (SLs) function in inhibiting axillary bud outgrowth. The roles of SLs in the regulation of bud outgrowth have been described in model plant species, including rice and Arabidopsis. However, the role of SLs genes in wheat remains elusive due to the size and complexity of the wheat genomes. In this study, TaD27 genes in wheat, orthologs of rice D27 encoding an enzyme involved in SLs biosynthesis, were identified. TaD27‐RNAi wheat plants had more tillers, and TaD27‐B‐OE wheat plants had fewer tillers. Germination bioassay of Orobanche confirmed the SLs was deficient in TaD27‐RNAi and excessive in TaD27‐B‐OE wheat plants. Moreover, application of exogenous GR24 or TIS108 could mediate the axillary bud outgrowth of TaD27‐RNAi and TaD27‐B‐OE in the hydroponic culture, suggesting that TaD27‐B plays critical roles in regulating wheat tiller number by participating in SLs biosynthesis. Unlike rice D27, plant height was not affected in the transgenic wheat plants. Transcription and gene coexpression network analysis showed that a number of genes are involved in the SLs signalling pathway and axillary bud development. Our results indicate that TaD27‐B is a key factor in the regulation of tiller number in wheat.

Summary Heterosis, or hybrid vigour, is a predominant phenomenon in plant genetics, serving as the basis of crop hybrid breeding, but the causative loci and genes underlying heterosis remain unclear in many crops. Here, we present a large‐scale genetic analysis using 5360 offsprings from three elite maize hybrids, which identifies 628 loci underlying 19 yield‐related traits with relatively high mapping resolutions. Heterotic pattern investigations of the 628 loci show that numerous loci, mostly with complete–incomplete dominance (the major one) or overdominance effects (the secondary one) for heterozygous genotypes and nearly equal proportion of advantageous alleles from both parental lines, are the major causes of strong heterosis in these hybrids. Follow‐up studies for 17 heterotic loci in an independent experiment using 2225 F2 individuals suggest most heterotic effects are roughly stable between environments with a small variation. Candidate gene analysis for one major heterotic locus (ub3) in maize implies that there may exist some common genes contributing to crop heterosis. These results provide a community resource for genetics studies in maize and new implications for heterosis in plants.

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.

The molecular mechanism of the maintenance and differentiation of plant stem cells is an eternal theme in studies on plant growth and development. Recent advances in single-cell RNA sequencing (scRNA-seq) methods have completely changed the understanding of cell heterogeneity and cell function, allowing research precision to identify the differentiation trajectory of stem cells maintained and differentiated at the cellular level. This review aimed to mainly discuss the novel insights provided by scRNA-seq for the maintenance and initiation of plant stem cells, cell differentiation, cell response to environmental changes, and improvement strategies for scRNA-seq. In addition, it highlighted additional perspectives beyond scRNA-seq, such as spatial transcriptomes, epigenomes, and single-cell multiomics, for a renewed understanding of stem cell maintenance and cell differentiation, thus providing potential targets and theoretical foundations for crop improvement.

The N6-methyladenosine (m6A) modification is the most common internal post-transcriptional modification, with important regulatory effects on RNA export, splicing, stability, and translation. Studies on the m6A modifications in plants have focused on Arabidopsis thaliana growth and development. However, A. thaliana is a salt-sensitive and model plant species. Thus, studies aimed at characterizing the role of the m6A modification in the salt stress responses of highly salt-tolerant crop species are needed. Sweet sorghum is cultivated as an energy and forage crop, which is highly suitable for growth on saline-alkaline land. Exploring the m6A modification in sweet sorghum may be important for elucidating the salt-resistance mechanism of crops. In this study, we mapped the m6A modifications in two sorghum genotypes (salt-tolerant M-81E and salt-sensitive Roma) that differ regarding salt tolerance. The m6A modification in sweet sorghum under salt stress was drastically altered, especially in Roma, where the m6A modification on mRNAs of some salt-resistant related transcripts increased, resulting in enhanced mRNA stability, which in turn was involved in the regulation of salt tolerance in sweet sorghum. Although m6A modifications are important for regulating sweet sorghum salt tolerance, the regulatory activity is limited by the initial m6A modification level. Additionally, in M-81E and Roma, the differences in the m6A modifications were much greater than the differences in gene expression levels and are more sensitive. Our study suggests that the number and extent of m6A modifications on the transcripts of salt-resistance genes may be important factors for determining and assessing the salt tolerance of crops.

Maize is an important crop worldwide, as well as a valuable model with vast genetic diversity. Accurate genome and annotation information for a wide range of inbred lines would provide valuable resources for crop improvement and pan-genome characterization. In this study, we generated a high-quality de novo genome assembly (contig N50 of 15.43 Mb) of the Chinese elite inbred line RP125 using Nanopore long-read sequencing and Hi-C scaffolding, which yield highly contiguous, chromosome-length scaffolds. Global comparison of the RP125 genome with those of B73, W22, and Mo17 revealed a large number of structural variations. To create new germplasm for maize research and crop improvement, we carried out an EMS mutagenesis screen on RP125. In total, we obtained 5818 independent M2 families, with 946 mutants showing heritable phenotypes. Taking advantage of the high-quality RP125 genome, we successfully cloned 10 mutants from the EMS library, including the novel kernel mutant qk1 (quekou: "missing a small part" in Chinese), which exhibited partial loss of endosperm and a starch accumulation defect. QK1 encodes a predicted metal tolerance protein, which is specifically required for Fe transport. Increased accumulation of Fe and reactive oxygen species as well as ferroptosis-like cell death were detected in qk1 endosperm. Our study provides the community with a high-quality genome sequence and a large collection of mutant germplasm.

Nitrogen is an essential macronutrient for plants and regulates many aspects of plant growth and development. Nitrate is one of the major forms of nitrogen in plants. However, the role of nitrate uptake and allocation in seed development is not fully understood. Here, we identified the maize (Zea mays) small-kernel mutant zmnpf7.9 and characterized the candidate gene, ZmNPF7.9, which was the same gene as nitrate transport 1.5 (NRT1.5) in maize. This gene is specifically expressed in the basal endosperm transfer layer cells of maize endosperm. Dysfunction of ZmNPF7.9 resulted in delayed endosperm development, abnormal starch deposition and decreased hundred-grain weight. Functional analysis of cRNA-injected Xenopus oocytes showed that ZmNPF7.9 is a low-affinity, pH-dependent bidirectional nitrate transporter. Moreover, the amount of nitrate in mature seeds of the zmnpf7.9 mutant was reduced. These suggest that ZmNPF7.9 is involved in delivering nitrate from maternal tissues to the developing endosperm. Moreover, most of the key genes associated with glycolysis/gluconeogenesis, carbon fixation, carbon metabolism and biosynthesis of amino acids pathways in the zmnpf7.9 mutant were significantly down-regulated. Thus, our results demonstrate that ZmNPF7.9 plays a specific role in seed development and grain weight by regulating nutrition transport and metabolism, which might provide useful information for maize genetic improvement.

Background: Pentatricopeptide repeat (PPR) proteins form a large protein family that participates in RNA processing in organelles and plant growth. Previous reports regard E-subgroup PPR proteins as editing factors for RNA editing. However, additional functions and roles of the E-subgroup PPR proteins remain to be investigated.Results: In this study, we developed and identified a new maize kernel mutant with arrested embryo and endosperm development, i.e., defective kernel 55 (dek55). Genetic and molecular evidence suggested that the defective kernels was a result of a mononucleotide alteration (C to T) at +449 bp in the open reading frame (ORF) of Zm00001d014471 (hereafter referred to as DEK55). DEK55 encodes an E-subgroup PPR protein within mitochondria. Molecular analyses showed that the editing ratio of 24 RNA editing sites was decreased and that of seven RNA editing sites was increased in dek55 mutant kernels, which were distributed in 14 mitochondrial gene transcripts. Meanwhile, the splicing efficiency of the nad1 introns 1 and 4 and nad4 intron 1 was significantly decreased in dek55 compared with that of wild-type (WT). These results indicate that DEK55 plays a crucial role in RNA editing at multiple sites as well as in the splicing of nad1 and nad4 introns. Mutation in the DEK55 gene led to the dysfunction of mitochondrial complex I. Yeast two-hybrid assays showed that the DEK55 interacts with two multiple organellar RNA editing factors (MORFs), i.e., ZmMORF1 (Zm00001d049043) and ZmMORF8 (Zm00001d048291), respectively.Conclusions: Our results demonstrated that a mutation in the DEK55 gene affects the mitochondrial function essential for maize kernel development. Our results also provide novel insight into the molecular functions of the E-subgroup PPR proteins in plant organellar RNA processing.

Cytokinins are a class of phytohormone that participate in the regulation of the plant growth, development, and stress response. In this review, the potential regulating mechanism during plant growth and stress response are discussed. Cytokinins are a class of phytohormone that participate in the regulation of plant growth, physiological activities, and yield. Cytokinins also play a key role in response to abiotic stresses, such as drought, salt and high or low temperature. Through the signal transduction pathway, cytokinins interact with various transcription factors via a series of phosphorylation cascades to regulate cytokinin-target gene expression. In this review, we systematically summarize the biosynthesis and metabolism of cytokinins, cytokinin signaling, and associated gene regulation, and highlight the function of cytokinins during plant development and resistance to abiotic stress. We also focus on the importance of crosstalk between cytokinins and other classes of phytohormones, including auxin, ethylene, strigolactone, and gibberellin. Our aim is to provide a comprehensive overview of recent findings on the mechanisms by which cytokinins act as central regulators of plant development and stress reactions, and highlight topics for future research.