Plant immune receptors such as the rice OsCERK1 protein is crucial for sensing immunogenic signal from pathogenic microbes and activate defenses. The immune activity of these immune receptors, however, must be tightly controlled to ensure normal growth when the pathogen is not present. How plants properly manage the speed of immune activation and stringent control is important for the survival of plants in a complex environment. A recent research discovered an E3 ligase, OsCIE1, that acts as a molecular brake controlling OsCERK1 activation in the absence of the immunogenic signal chitin. OsCIE1 inhibits the kinase activity of OsCERK1 by ubiquitination, thereby negatively regulating immunity. Upon perception of chitin, OsCERK1 phosphorylates OsCIE1 to inhibit the E3 ligase activity, thereby releasing the brake and allowing robust activation of defenses.

Living organisms are often exposed to a wide range of biotic and abiotic stresses that cause severe wounding, leading to partial or complete organ loss. Being sessile, plants have evolved powerful regenerative capabilities to adapt to the environment. Wounding is a prerequisite for plant regeneration, the local wound signals that trigger regenerative responses remained unknown for centuries. A recent study has identified a small peptide, REF1, that regulates local wound responses and regeneration capabilities in plants. The study found that REF1 and its receptor PORK1 can promote plant regeneration by activating WIND1, a master regulator of wound-induced cellular reprogramming in plants. Crucially, exogenous application of the REF1 peptide can improve the regeneration efficiency of several crops to varying degrees. This discovery not only provides a new perspective on the molecular mechanisms of plant injury responses and regene- ration, but also offers potential application strategies for enhancing the regenerative capacity and transformation efficiency of crops.

The numerous flowering genes that have been identified in different plants play a crucial role in determining whether a plant is annual or perennial. However, the evolutionary mechanism by which these flowering genes drive the transition between annual and perennial life history strategies in Brassicaceae plants remains poorly understood. A recent study focused on natural variations in different genera of Brassicaceae. They identified three closely related MADS-box transcription factor genes, namely FLC, FLM, and MAF, and elucidated their molecular mechanisms associated with the transition between annual and perennial behavior. Their findings suggest that the life-history strategy in Brassicaceae plants (i.e., the conversion between perennial, biennial, and annual behavior) is a continuum determined by the dosage of FLC-like MADS-box genes. The study elucidates the evolutionary mechanisms and trajectories underlying the reciprocal conversion of life history strategies from annual to perennial in Brassicaceae, providing a theoretical foundation for breeding perennial rapeseed varieties and offering insights for Brassicaceae crops improved towards perennial grain.

Higher plants usually start from seed germination and re-form seeds after vegetative growth and reproductive development, thus completing the life cycle. Carbohydrates, lipids, proteins, mRNA and other macromolecular substances accumulated in seeds are crucial to maintain the germination potential of seeds, some of mRNA can be preserved for a long time without degradation, known as long-lived mRNA. In rice, long-lived mRNA associated with germination began to be transcribed and accumulated 10 to 20 days after flowering, and some long-lived mRNA associated with dormancy and stress response were transcribed and preserved in cells from 20 days after flowering to seed maturity. There are many kinds of long-lived mRNA, mainly including some protein synthesis mRNA, energy metabolism mRNA, cytoskeleton mRNA and some stress response related mRNA, such as small heat shock protein, LEA (late embryogenesis abundant) family proteins. Transcriptomic analysis found that the promoter regions of many genes contain ABA- or GA-associated cis-acting elements, and there are about 500 differentially expressed long-lived mRNAs in the Arabidopsis atabi5 (ABA-insensitive 5) mutant seeds that differ from the wild type, suggesting that abscisic acid (ABA) and gibberellin (GA) are the key hormones that influence the type of long-lived mRNA. Long-lived mRNAs are usually cross-linked with a single ribosome, RNA binding protein, which exists in cells in the form of P-bodies (PBs) to protect the mRNA from degradation. However, long-lived mRNAs associated with seed dormancy are gradually degraded during seed post-ripening, and the oxidative modification of some specific long-lived mRNAs is also a biological phenomenon to break seed dormancy. During the long-term storage of seeds, the random degradation of long-lived mRNA is directly related to the life and vitality of seeds, and the retained mRNA is translated into protein to help the rapid germination of seeds in the early stage of imbibition. In this paper, the characteristics and functions of long-lived mRNA are reviewed, and some future scientific issues are discussed to provide a reference for further understanding of the molecular mechanisms of seed dormancy, germination and longevity.

Flowering time is a critical point in the life cycle of angiosperm plants. Arabidopsis thaliana of the Brassicaceae is widely distributed around the world, and the natural populations of this species have been found at altitude 4 000 m in the Qinghai-Tibet Plateau. The cold/short summer plateau climate has shaped their flowering time to be moderately early compared with those living in low altitude areas. In this study, we constructed an F₂ mapping population and utilized whole-genome sequencing-based QTL-seq analysis to locate the major effect QTLs in Lhasa population of A. thaliana, and identified a haplotype-specific deletion of 2 307 bp within the first intron of FLC, which is unique to Tibetan A. thaliana. Lhasa population flc^-/- mutant was constructed by CRISPR-Cas9 gene editing technique. The mutant exhibited significantly earlier flowering time than Lhasa. The above findings suggested that the deletion in the first intron of FLC in Tibetan A. thaliana was most likely the major cause for the early flowering phenotype, although it did not cause complete function loss of the FLC. This variation may have facilitated the adaptation of Tibetan A. thaliana to the unique climatic environment of the Qinghai-Tibet Plateau.

Agropyron mongolicum is one of northern China’s most representative perennial forage grasses, showing strong tolerance to cold and drought. In plants, caffeic acid O-methyltransferase (COMT) is a key gene involved in the biosynthesis of lignin and melatonin, and plays an important role in regulating plant growth, biomass quality, and stress tolerance. In this study, through the analysis of the full-length transcriptome data of A. mongolicum, the COMT candidate gene AmCOMT1 was cloned. AmCOMT1 is highly expressed in tissues with high lignin content, such as stem and root, and its expression is induced by a variety of abiotic stresses, including drought and salt. Overexpression of AmCOMT1 in Arabidopsis wild type (Col-0) and mutant (omt1-2) significantly promoted the synthesis of lignin in transgenic Arabidopsis, restoring the lignin content and composition of the mutant to wild type level and the lignin content in Col-0/35S:AmCOMT1 was increased by 11%. In addition, overexpression of AmCOMT1 increased the melatonin content in Col-0/35S:AmCOMT1 transgenic Arabidopsis. Under salt stress conditions, the average root length of this transgenic line increased by 20.3% compared to the wild type, showing higher stress tolerance. In this study, we identified AmCOMT1 from A. mongolicum as a key gene regulating both lignin biosynthesis and melatonin biosynthesis, improving the stress tolerance of transgenic Arabidopsis. Our results highlighted the application potential of AmCOMT1 in genetic improvement of forage grasses through molecular breeding.

INTRODUCTION Nitrogen (N) is one of the most essential nutrients for the plant growth and development, and NH₄⁺-N is the main form of N source. Appropriate amount of NH₄⁺ promotes plant growth and increase crop yield. However, when used as the only N source, NH₄⁺ suppresses the growth and production of crops. Wheat (Triticum aestivum) is the third largest cereal crop in China, and its production has a profound impact on the food production. As the indispensable raw material for foods, wheat is crucial to daily life, so studying NH₄⁺ toxicity and mitigation mechanisms are of great significance for wheat production.

RATIONALE NH₄⁺toxicity is a ubiquitous issue in plants. The mechanisms of how NH₄⁺ causes phytotoxicity are not fully understood. To explore the mechanisms of NO₃^--dependent alleviation of NH₄⁺toxicity in the roots of wheat, both transcriptomic and proteomic approaches were used to investigate the differential expressions of genes and proteins under different nitrogen treatments.

RESULTS Compared with 7.5 mmol·L^-1NO₃^- (control), 7.5 mmol·L^-1NH₄⁺treatment inhibited the root growth of wheat seedlings. Transcriptome analysis showed that sole NH₄⁺ treatment upregulated the expressions of genes encoding glycolysis- and fermentation-related enzymes, including pyruvate decarboxylase, alcohol dehydrogenase and lactate dehydrogenase, while downregulated the expressions of genes encoding TCA cycle enzymes and the ATP synthases in the roots compared with control. Expressions of genes encoding the respiratory burst oxidase homologs (Rbohs), alternative oxidase (AOX) and dioxygenases were significantly upregulated, and expression of the PIP-type aquaporin genes were downregulated. The addition of 1 mmol·L^-1NO₃^- to the solution containing 7.5 mmol·L^-1NH₄⁺downregulated the expression of genes encoding glycolysis enzymes, fermentation enzymes, Rbohs, AOX and dioxygenases, and increased the expression of genes encoding the TCA cycle enzymes, the ATP synthases and PIP-type aquaporins. Proteome analysis showed that expressions of glycolysis enzymes, fermentation enzymes and AOX were upregulated, while PIP-type aquaporins were downregulated under sole NH₄⁺conditions compared with the control. The addition of NO₃^- downregulated the expressions of glycolysis enzymes, fermentation enzymes, Rbohs and AOX and upregulated expressions of PIP-type aquaporins.

CONCLUSION In conclusion, sole NH₄⁺ treatment promotes glycolytic and fermentation pathways, inhibits the TCA cycle and energy generation, and ultimately inhibits root growth of wheat seedlings. The inhibition of root growth may be due to the sole NH₄⁺-induced hypoxic stress in the roots. The addition of NO₃^- inhibits the glycolysis and fermentation pathways, promotes the TCA cycle and energy production, significantly alleviates the hypoxia stress and thereby attenuates the inhibitory effect of NH₄⁺ on root growth.

INTRODUCTION Sexual differentiation of plants, as known as dioecy, is the phenomenon of sexually dimorphic traits, which means that the female and male reproductive organs are on different individuals. In agronomic or economic ap- plications, dioecy is not a desired character for various reasons. Therefore, a simple and effective method for distin- guishing female and male individuals is a common goal for the people in many fields. As so far, molecular marker is a gold standard for sex identification genetically. It is necessary to develop a molecular technique to detect sexual systems in the dioecious plants.

RATIONALEIn plants, the origin and evolution of sex chromosomes was independent in many species, therefore sex determination region/chromosome was different among them. Idesia polycarpa is a deciduous tree, making it an attrac- tive model system with which to study sex determination mechanism. We characterized the re-sequence data of female and male individuals from natural population. We used these data to identify the sex determination systems by statistics unique sequences in females and males. To detect the sex chromosome, we analysed the single nucleotide polymor- phisms (SNPs) by genome-wide association study (GWAS).

RESULTSThe information of genome contains the secret code of various traits, so we mined the re-sequenced data of females and males. We calculated the common and unique reads in females and males, compared the unique reads between them, and found that the unique reads of females were much more than that of males. The result suggested that the sex determination system of I. polycarpa was ZW/ZZ. We then identified 30 million high quality SNPs in the population by mapping to the reference genome, calculated the p value of each SNP, drew a Manhattan plot. The result showed the highest peak on the end of 19 chromosome. We analysed the heterozygote of SNPs in this peak, and the result showed that the SNPs were heterozygotic in females, but homozygotic in males. The result confirmed that the sex determination system in I. polycarpa is ZW/ZZ. Further, a cleave amplified polymorphic sequences (CAPS) mo- lecular marker was developed according to the significant SNPs, and was successfully applied to different female and male individuals.

CONCLUSION In the Salicaceae family, there were two kinds of sex determination system, one is XX/XY (females are homogametic XX, and males are heterogametic XY), another is ZW/ZZ (females are heterogametic ZW, and males are homogametic ZZ). At present, most studies on the sex-determining regions and genes in the Salicaceae family are carried out by methods such as genome, transcriptome, and resequencing analyses. Our results showed that the sex determination system in I. polycarpawas ZW/ZZ, and the 19^th chromosome is most likely associated with sex determination. And a CAPS molecular marker was developed, which is a simple and fast method for efficient identification sex at seedling stage. The research provided a useful way to the planting pattern of I. polycarpa.

Flower size is a key factor in plant evolution and speciation, and also an important trait that determines plant ornamental value, so it is of great scientific significance and practical value to study the inheritance law and regulatory mechanism of floral size. To clarify the inheritance law of flower size in petunia, the inbred lines and wild species of Petunia hybrida with different flower sizes were used to make cross combinations and construct genetic populations in this study, including large-flowered line × medium-flowered lines (W × S26 and W × S) and large-flowered line × small-flowered line (W × S6). The results showed that all F₁ generation of W × S26 were large-flowered plants, while the flower size appeared separation in F₂ population with the ratio between large-and medium-flowered individuals of about 3:1, and the segregation ratio between large- and medium-flowered plants was close to 1:1 in the BC₁ backcross population. For the W × S combination, all F₁ individuals were large-flowered, while the flower size appeared separation in the F₂ population, with large- to medium-flowered plants close to 2:1. The F₁ progenies of W × S6 are all medium-flowered plants, while the flower size of the F₂ generation showed evident variation and continuous distribution. Performing mixed major gene plus polygene inheritance model analysis, the optimal models for W × S26 and W × S combination were 1MG-AD and 2MG-EAD, respectively, according to the standard of minimum AIC value. It is reasonable to conclude that the large flower trait of the inbred line W is controlled by a single dominant gene related to the middle flower trait of S26, with additive dominant effect, whereas the large flower of the inbred line W is controlled by two major genes related to the small flower of the inbred lines with equal additive dominant effect. In addition, nine genes that may regulate flower size of petunia were selected based on the transcriptomic analysis of large and small flowers, and their expression levels were detected in the petals of various strains with different flower sizes by qRT-PCR. The results showed that the expression levels of cytokinin receptor gene PhHK and Type-A RRs in response to cytokinin signal were generally higher in large flowers than in medium and small flowers, suggesting that cytokinin signaling pathway may be a key factor involved in regulating the large flower trait in petunia.

In order to establish an in vitro regeneration system for Lunaria annua, its true leaves were used as explants to study the effects of sterilization conditions, combinations and concentrations of plant growth regulator on the induction of callus and on the differentiation of adventitious buds and roots; The effect of rooting methods on the growth of seedlings and young plants was further explored. The results showed that the best disinfection treatment for leaf explants was a combination of 75% alcohol for 45 seconds and 0.1% HgCl₂ solution for 6 minutes. The most suitable medium for induction of callus and differentiation of adventitious buds was MS+0.5 mg∙L^-1 6-BA+2.0 mg∙L^-1 2,4-D. The induction rate of callus reached 93.37% and the differentiation rate of adventitious buds reached 84.08%. The best rooting medium was MS+0.1 mg∙L^-1 NAA, and the time from inoculating leaf explants to obtaining regenerated plants was about 90 days. In this study, a stable regeneration system was established, which laid a foundation for the development and utilization of L. annua resources and digging for functional genes.

An in vitro rapid propagation system using scale buds of Itoh hybrids ‘He Xie’ can overcome the shortcomings of the slow traditional breeding methods and promote the adoption of the excellent Itoh hybrid varieties. In this study, we used the buds of ‘He Xie’ as explants to investigate the effects of various factors including disinfection time, plant growth regulators (PGRs) concentration and root induction time, and different rooted seedling grades on the initiation, proliferation, rooting and domestication of ‘He Xie’ with one-way experimental design. Our results showed: the optimal disinfection time of buds by 2% sodium hypochlorite solution was 12 min, with a contamination rate of 9.09%; the optimal initial culture medium was MS+1.5 mg∙L^-1 6-BA+0.2 mg∙L^-1 GA₃+0.5 mg∙L^-1 AgNO₃; the optimal proliferation culture medium was MS+450 mg∙L^-1 CaCl₂+0.5 mg∙L^-1 6-BA+0.2 mg∙L^-1 IBA+0.2 mg∙L^-1 GA₃+0.5 mg∙L^-1 AgNO₃ with a proliferation rate of 3.3. Rootless seedlings were cultured on root induction medium 1/2MS+1.0 mg∙L^-1 putrescine+2.0 mg∙L^-1 IBA for 8 d at 4°C in dark and then 30 d at room temperature under light, and finally transferred to root formation medium 1/2MS+1.0 g∙L^-1 AC for 20 d, a rooting rate of 66.7% was observed. The rooted seedlings were transplanted on a growing matrix of perlite:vermiculite:charcoal soil=1:1:1 (v/v/v) for 60 d, with the highest transplant survival rate of 52.0% being observed for first-grade rooted seedlings, but most of the second- and third-grade seedlings being dead, suggesting that the quality of rooting is critical for transplant survival.

As a new technology for targeted genome editing, clustered regularly interspaced short palindromic repeat (CRISPR) and CRISPR-associated protein (Cas) have the advantages of easy operation, high editing efficiency, and support for multi-target editing, thus showing wide application prospects in plant genetic breeding. However, the process in plants relies mainly on Agrobacterium- or particle bombardment-mediated genetic transformation, which is time-consuming as well as species- and varieties-dependent. Virus-mediated plant genome editing has attracted extensive atten- tion because of its no requirement of genetic transformation and plant regeneration. In this review, we introduce the working principle and advantages of virus-mediated CRISPR/Cas plant genome editing technology, systematically sum- marize the current application status of this technology in the field of plant genome editing, and focus on discussing the problems and challenges of this technology system, aiming to provide reference for further research and development in this field.

Flavonoids are polyphenols compounds produced during the secondary metabolism of plants, which are widely present in plants and have various functions. Flavonoids biosynthesis takes place at the cytosolic side of the en- doplasmic reticulum (ER), but accumulation of various flavonoids is observed in the vacuole. Efficient transport and ac- cumulation systems are therefore required to transfer flavonoids from the ER into the vacuole. Certain researches for the transport of flavonoids has been done for decades. Current research results showed that: there are three transport mechanisms in plants, including glutathione S-transferase (GST), membrane transporters, and vesicle trafficking. Here, we reviewed the three transport mechanisms and advances of plant flavonoids transport in recent years. The functional cooperation of three distinct but nonexclusive mechanisms were summarized. While the biosynthesis of the flavonoids is well characterized across species, the research on flavonoids transport and accumulation is still relatively insufficient. For better understand the flavonoids transport and accumulation mechanism in plant, the relationship between flavonoids modification and transport, flavonoids transport substrate specificity and preference, and transcriptional regulation of flavonoids transport remain deeply unexplored.

Organisms have evolved different photoreceptors to adapt to the ever-changing conditions of the external light environment. Phytochromes (phys) are one of the classic plant photoreceptors, mainly perceiving red and far-red light. Phytochromes detect red and far-red light through the light conversion between the dark-adapted Pr state and the light-activated Pfr state. All plant phytochromes have a conserved N-terminal photoreceptor region and a C-terminal regulatory region. The N-terminal includes NTE, PAS, GAF, and PHY subdomains, while C-terminal includes two PAS domains and a histidine kinase-related domain (HKRD). In order to understand how the structure of photochromes controls its function, many function-deficient photochrome derivatives and amino acid point mutants have been obtained and studied. The N-terminal domain plays important roles in the spectral properties, light signal perception and light signal transduction of phyB. The C-terminal domain is essential for dimerization and nuclear localization of photochrome. This paper mainly reviews point mutations of amino acid in various subdomains of phyB in Arabidopsis thaliana and their effects on the function of phyB, in order to have a better understanding of the structure and functional regulation of phyB. It lays a foundation for obtaining crops with desired agronomic characteristics through gene editing.

Pteridophytes (lycophytes and ferns) are the second most diverse lineage of vascular plants on the earth. These plants share several morphological and physiological traits with other vascular and sporophyte plants, and play a vital role in the evolutionary progression of land plants from simple to complex forms. Pteridophytes exhibit many unique biological processes different from other plant groups, and play a key role in the study of plant genome evolution, organ development, reproductive phenomena, and adaptation to changing environment. The advancement and implementation of modern sequencing technology has greatly accelerated the sequencing and assembly of plant genomes, and greatly promoted the exploration gene function of pteridophytes. To gain an enhanced comprehension of the present interesting fields and noteworthy development in functional genomics research of pteridophytes, this article provides a thorough overview of the functional investigation of pteridophyte genes from various perspectives. It mainly focuses on the development of organs, reproductive processes, adaptability to the environment, and the synthesis of secondary metabolites. It presents a systematic exploration of the functions of multiple genes, highlighting the practical implementation of gene function research in clarifying the unique biological processes specific to pteridophytes. In addition, this article puts forward several recommendations on how to expedite the research on gene function of pteridophytes, and to take advantage of function studies in exploring the biological characteristics of terrestrial plants and expanding the application scope of pteridophytes.