The grass family is one of the largest families in angiosperms and has evolved a characteristic inflorescence morphology, with complex branches and specialized spikelets. The origin and development ...of the highly divergent inflorescence architecture in grasses have recently received much attention. Increasing evidence has revealed that numerous factors, such as transcription factors and plant hormones, play key roles in determining reproductive meristem fate and inflorescence patterning in grasses. Moreover, some molecular switches that have been implicated in specifying inflorescence shapes contribute significantly to grain yields in cereals. Here, we review key genetic and molecular switches recently identified from two model grass species, rice (Oryza sativa) and maize (Zea mays), that regulate inflorescence morphology specification, including meristem identity, meristem size and maintenance, initiation and outgrowth of axillary meristems, and organogenesis. Furthermore, we summarize emerging networks of genes and pathways in grass inflorescence morphogenesis and emphasize their evolutionary divergence in comparison with the model eudicot Arabidopsis thaliana. We also discuss the agricultural application of genes controlling grass inflorescence development.
•We review diverse LRR-RLK signaling pathways in promoting tapetal cell identity.•We summarize redox state in specifying germ cell and tapetum fate.•We address tapetal cell fate control regulated by ...reproductive cells.•We present an emerging regulatory network of transcription factors and miRNAs in early anther development.
Flowering plants form male reproductive cells (microsporocytes) during sporophytic generation, which subsequently differentiate into multicellular male gametes in the gametophytic generation. The tapetum is a somatic helper tissue neighboring microsporocytes and supporting gametogenesis. The mechanism controlling the specification of the tapetum and microsporocyte cell fate within the anther has long been a mystery in biology. Recent investigations have revealed molecular switches and signaling pathways underlying the establishment of somatic and reproductive cells in plants. In this review we discuss common and diversified signaling molecules and regulatory pathways including receptor-like protein kinases, redox status, glycoprotein, transcription factors, hormones and microRNA implicated in the specification of tapetum and microsporocytes in plants.
Nanotechnology has become one of the most promising technologies applied in all areas of science. Metal nanoparticles produced by nanotechnology have received global attention due to their extensive ...applications in the biomedical and physiochemical fields. Recently, synthesizing metal nanoparticles using microorganisms and plants has been extensively studied and has been recognized as a green and efficient way for further exploiting microorganisms as convenient nanofactories. Here, we explore and detail the potential uses of various biological sources for nanoparticle synthesis and the application of those nanoparticles. Furthermore, we highlight recent milestones achieved for the biogenic synthesis of nanoparticles by controlling critical parameters, including the choice of biological source, incubation period, pH, and temperature.
As genomes of many plant species have been sequenced, demand for functional genomics has dramatically accelerated the improvement of other omics including metabolomics. Despite a large amount of ...metabolites still remaining to be identified, metabolomics has contributed significantly not only to the understanding of plant physiology and biology from the view of small chemical molecules that reflect the end point of biological activities, but also in past decades to the attempts to improve plant behavior under both normal and stressed conditions. Hereby, we summarize the current knowledge on the genetic and biochemical mechanisms underlying plant growth, development, and stress responses, focusing further on the contributions of metabolomics to practical applications in crop quality improvement and food safety assessment, as well as plant metabolic engineering. We also highlight the current challenges and future perspectives in this inspiring area, with the aim to stimulate further studies leading to better crop improvement of yield and quality.
Increasing crop production to meet the demands of a growing population depends largely on crop improvement through new plant-breeding techniques (NPBT) such as genome editing. CRISPR/Cas systems are ...NPBTs that enable efficient target-specific gene editing in crops, which is supposed to accelerate crop breeding in a way that is different from genetically modified (GM) technology. Herein, we review the applications of CRISPR/Cas systems in crop breeding focusing on crop domestication, heterosis, haploid induction, and synthetic biology, and summarize the screening methods of CRISPR/Cas-induced mutations in crops. We highlight the importance of molecular characterization of CRISPR/Cas-edited crops, and pay special attentions to emerging highly specific genome-editing tools such as base editors and prime editors. We also discuss future improvements of CRISPR/Cas systems for crop improvement.
Phosphate is an essential macro-element for plant growth accumulated in the topsoil. The improvement of phosphate uptake efficiency via manually manipulating root system architecture is of vital ...agronomic importance. This review discusses the molecular mechanisms of root patterning in response to external phosphate availability, which could be applied on the alleviation of phosphate-starvation stress. During the long time evolution, plants have formed sophisticated mechanisms to adapt to environmental phosphate conditions. In terms of root systems, plants would adjust their root system architecture via the regulation of the length of primary root, the length/density of lateral root and root hair and crown root growth angle to cope with different phosphate conditions. Finally, plants develop shallow or deep root system in low or high phosphate conditions, respectively. The plasticity of root system architecture responds to the local phosphate concentrations and this response was regulated by actin filaments, post-translational modification and phytohormones such as auxin, ethylene and cytokinin. This review summarizes the recent progress of adaptive response to external phosphate with focus on integrated physiological, cellular and molecular signaling transduction in rice and
.
The pollen wall is a specialized extracellular cell wall matrix that surrounds male gametophytes and plays an essential role in plant reproduction. Uncovering the mechanisms that control the ...synthesis and polymerization of the precursors of pollen wall components has been a major research focus in plant biology. We review current knowledge on the genetic and biochemical mechanisms underlying pollen wall development in eudicot model Arabidopsis thaliana and monocot model rice (Oryza sativa), focusing on the genes involved in the biosynthesis, transport, and assembly of various precursors of pollen wall components. The conserved and divergent aspects of the genes involved as well as their regulation are addressed. Current challenges and future perspectives are also highlighted.
Pollen wall development exhibits conserved and diversified features.
Genes associated with pollen wall development are coordinately regulated.
The synthesis of exine and anther cutin may share common pathways in rice.
Microsporogenesis and male gametogenesis are essential for the alternating life cycle of flowering plants between diploid sporophyte and haploid gametophyte generations. Rice （Oryza sativa） is the ...world＇s major staple food, and manipulation of pollen fertility is particularly important for the demands to increase rice grain yield. Towards a better understanding of the mechanisms controlling rice male reproductive development, we describe here the cytological changes of anther development through 14 stages, including cell division, differentiation and degeneration of somatic tissues consisting of four concentric cell layers surrounding and supporting reproductive cells as they form mature pollen grains through meiosis and mitosis. Furthermore, we compare the morphological difference of anthers and pollen grains in both monocot rice and eudicot Arabidopsis thaliana. Additionally, we describe the key genes identified to date critical for rice anther development and pollen formation.
Medicinal plants are essential for improving human health, and around 75% of the population in developing countries relies mainly on herb-based medicines for health care. As the king of herb plants, ...ginseng has been used for nearly 5000years in the oriental and recently in western medicines. Among the compounds studied in ginseng plants, ginsenosides have been shown to have multiple medical effects such as anti-oxidative, anti-aging, anti-cancer, adaptogenic and other health-improving activities. Ginsenosides belong to a group of triterpene saponins (also called ginseng saponins) that are found almost exclusively in Panax species and accumulated especially in the plant roots. In this review, we update the conserved and diversified pathway/enzyme biosynthesizing ginsenosides which have been presented. Particularly, we highlight recent milestone works on functional characterization of key genes dedicated to the production of ginsenosides, and their application in engineering plants and yeast cells for large-scale production of ginsenosides.
Key message
Several QTLs and genes responsible for seed dormancy were detected and SNP candidates were shown to cause changes in seed germination.
Seed dormancy is a key agricultural trait to prevent ...pre-harvest sprouting in crop plants such as rice (
Oryza sativa
L.), wheat (
Triticum aestivum
), and barley (
Hordeum vulgare
L.). However, our knowledge of seed dormancy is hampered by the complexities of studying a trait that changes over time after seed harvest, and is complicated by interactions between phytohormones, seed coat components and the environment. Here, we have conducted a genome-wide association study using a panel of 311 natural accessions of cultivated rice, examining a total of 519,158 single nucleotide polymorphisms (SNPs). Eight quantitative trait loci (QTLs) were found to associate with seed dormancy in the whole panel and five in the
Japonica
and
Indica
subpanel; expression of candidate genes within 100 kb of each QTL was examined in two published, germination-specific transcriptomic datasets. Ten candidate genes, differentially expressed within the first four days post-imbibition, were identified. Five of these genes had previously been associated with awn length, heading date, yield, and spikelet length phenotypes. Two candidates were validated using Quantitative Reverse Transcription (qRT)-PCR. In addition, previously identified genes involved in hormone signaling during germination were found to be differentially expressed between a
japonica
and an
indica
line; SNPs in the promoter of
Os9BGlu33
were associated with germination index, with qRT-PCR validation. Collectively, our results are useful for future characterization of seed dormancy mechanism and crop improvement, and suggest haplotypes for further analysis that may be of use to boost PHS resistance in rice.
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