Plants maintain the ability to form lateral appendages throughout their life cycle and form leaves as the principal lateral appendages of the stem. Leaves initiate at the peripheral zone of the shoot apical meristem a...Plants maintain the ability to form lateral appendages throughout their life cycle and form leaves as the principal lateral appendages of the stem. Leaves initiate at the peripheral zone of the shoot apical meristem and then develop into flattened structures. In most plants, the leaf functions as a solar panel, where photosynthesis converts carbon dioxide and water into carbohydrates and oxygen. To produce structures that can optimally fulfill this function, plants precisely control the initiation, shape, and polarity of leaves. Moreover, leaf development is highly flexible but follows common themes with conserved regulatory mechanisms. Leaves may have evolved from lateral branches that are converted into determinate, flattened structures. Many other plant parts, such as floral organs, are considered specialized leaves, and thus leaf development underlies their morphogenesis. Here, we review recent advances in the understanding of how threedimensional leaf forms are established. We focus on how genes, phytohormones, and mechanical properties modulate leaf development, and discuss these factors in the context of leaf initiation, polarity establishment and maintenance, leaf flattening, and intercalary growth.展开更多
Leaf morphogenesis is strictly controlled not only by intrinsic genetic factors, such as transcriptional factors, but also by environmental cues, such as light, water and pathogens. Nevertheless, the molecular mechani...Leaf morphogenesis is strictly controlled not only by intrinsic genetic factors, such as transcriptional factors, but also by environmental cues, such as light, water and pathogens. Nevertheless, the molecular mechanism of how leaf morphogenesis is regulated by genetic programs and environmental cues is far from clear. Numerous series of events demonstrate that plant hormones, mostly small and simple molecules, play crucial roles in plant growth and development, and in responses of plants to environmental cues such as light. With more and more genetics and molecular evidence obtained from the model plant Arabidopsis, several fundamental aspects of leaf morphogenesis including the initiation of leaf primordia, the determination of leaf axes, the regulation of cell division and expansion in leaves have been gradually unveiled. Among these phytohormones, auxin is found to be essential in the regulation of leaf morphogenesis.展开更多
Maca （Lepidium meyenii Walp, 2n = 8x = 64）, belonging to the Brassicaceae family, is an economic plant cultivated in the central Andes sierra in Peru （4000-4500 m）. Considering that the rapid uplift of the central...Maca （Lepidium meyenii Walp, 2n = 8x = 64）, belonging to the Brassicaceae family, is an economic plant cultivated in the central Andes sierra in Peru （4000-4500 m）. Considering that the rapid uplift of the central Andes occurred 5-10 million years ago （Ma）, an evolutionary question arises regarding how plants such as maca acquire high-altitude adaptation within a short geological period. Here, we report the high-quality genome assembly of maca, in which two closely spaced maca-specific whole-genome duplications （WGDs; ~6.7 Ma） were identified. Comparative genomic analysis between maca and closely related Brassicaceae species revealed expansions of maca genes and gene families involved in abiotic stress response, hormone signaling pathway, and secondary metabolite biosynthesis via WGDs. The retention and subsequent functional divergence of many duplicated genes may account for the morphological and physiological changes （i.e., small leaf shape and self-fertility） in maca in a high-altitude environment. In addition, some duplicated maca genes were identified with functions in morphological adaptation （i.e., LEAF CURLING RESPONSIVENESS） and abiotic stress response （i.e., GL YClNE-RICH RNA-BINDING PROTEINS and DNA-DAMAGE-REPAIR/TOLERATION2） under positive selection. Collectively, the maca genome provides use- ful information to understand the important roles of WGDs in the high-altitude adaptation of plants in the Andes.展开更多
Floral morphogenesis and the development of Cercidiphyllumjaponicum Sieb. et Zucc. were observed by scanning electron microscopy （SEM）. The results showed that the pistillate inflorescences were congested spikes wit...Floral morphogenesis and the development of Cercidiphyllumjaponicum Sieb. et Zucc. were observed by scanning electron microscopy （SEM）. The results showed that the pistillate inflorescences were congested spikes with the flowers arranged opposite. Great differences between the so-called ＂bract＂ and the vegetative leaf were observed both in morphogenesis and morphology. In morphogenesis, the ＂bract＂ primordium is crescent-shaped, truncated at the apex and not conduplicate, has no stipule primordium at the base but does have some inconspicuous teeth in the margin that are not glandular. The leaf primordium is triangular, cycloidal at the apex, conduplicate, has two stipule primordia at the base, has one gland-tooth at the apex occurring at first and some gland-teeth in the margin that occur later. In morphology, the ＂bract＂ is also different to the vegetative leaf in some characteristics that were also illustrated in the present paper. Based on the hypothesis that the bract is more similar to the vegetative leaf than the tepal, we considered that the so-called ＂bract＂ of C.japonicum might be the tepal of the pistillate flower in morphological nature. Therefore, each pistillate flower contains a tepal and a carpel. We did not find any trace of other floral organs in the morphogenesis of the pistillate flower. Therefore we considered that the unicarpellate status of extant Cercidiphyllum might be to highly reduce and advance characteristics that make the extant Cercidiphyllum isolated from both fossil Cercidiphyllum-like plants and its extant affinities.展开更多
An ideal leaf shape is beneficial to the yield of rice.Molecular understanding of the leaf primordia and polarity establishment plays a significant role in exploring the genetic regulatory network of leaf morphogenesi...An ideal leaf shape is beneficial to the yield of rice.Molecular understanding of the leaf primordia and polarity establishment plays a significant role in exploring the genetic regulatory network of leaf morphogenesis.In recent years,researchers have cloned an array of coding genes and a few non-coding small RNAs involved in rice leaf development through regulating the development of leaf primordia,vascular bundles,sclerenchyma cells,bulliform cells,cell walls and epidermis cells.These genes and their interactions play critical roles in rice leaf development through the determination and regulatory role in gene expression,and their coordination with other genetic networks or signal pathways.But the relationship among these genes is poorly defined and the underlying network is still unclear.In this review,we introduced the regulatory pathways of leaf primordium development and leaf polarity establishment,mainly the relationship between cell development mechanism and leaf polarity establishment,focusing on how leaf tissue affects leaf shape.Hopefully,the regulation network reviewed here has immediate implications for future research and genomic design breeding.展开更多
同源异型盒基因KNOX1(class I KNOTTED-like homeobox)广泛存在于植物中,具备调控和维持茎顶端分生组织活性的功能。近年来研究发现,KNOX1基因家族参与植物激素调控和各个器官的形态建成,尤其对植物花和叶的发育有着重要作用。本文介绍...同源异型盒基因KNOX1(class I KNOTTED-like homeobox)广泛存在于植物中,具备调控和维持茎顶端分生组织活性的功能。近年来研究发现,KNOX1基因家族参与植物激素调控和各个器官的形态建成,尤其对植物花和叶的发育有着重要作用。本文介绍了KNOX1的表达模式,与植物激素的调控作用,在花和叶形态建成中的功能,并综述了拟南芥中KNOX1的相互作用因子及其功能,为进一步阐明KNOX1在植物发育中的分子机制提供参考。最后展望了未来KNOX1的研究方向及发展趋势。展开更多
Plants produce a rich diversity of biological forms,and the diversity of leaves is especially notable.Mechanisms of leaf morphogenesis have been studied in the past two decades,with a growing focus on the interactive ...Plants produce a rich diversity of biological forms,and the diversity of leaves is especially notable.Mechanisms of leaf morphogenesis have been studied in the past two decades,with a growing focus on the interactive roles of mechanics in recent years.Growth of plant organs involves feedback by mechanical stress:growth induces stress,and stress affects growth and morphogenesis.Although much attention has been given to potential stress-sensing mechanisms and cellular responses,the mechanical principles guiding morphogenesis have not been well understood.Here we synthesize the overarching roles of mechanics and mechanical stress in multilevel and multiple stages of leaf morphogenesis,encompassing leaf primordium initiation,phyllotaxis and venation patterning,and the establishment of complex mature leaf shapes.Moreover,the roles of mechanics at multiscale levels,from subcellular cytoskeletal molecules to single cells to tissues at the organ scale,are articulated.By highlighting the role of mechanical buckling in the formation of three-dimensional leaf shapes,this review integrates the perspectives of mechanics and biology to provide broader insights into the mechanobiology of leaf morphogenesis.展开更多
基金The work of the authors is funded by the National Basic Research Program of China （973 Program） grant 2014CB943500, the National NaturalScience Foundation of China grants 31430010, 31401232, 31872835, and 3171101408, and partly supported by the open funds of the State Key Laboratory of Plant Physiology and Biochemistry （SKLPPBKF1805）. Y.J. is a Newton Advanced Fellow of the Royal Society.
文摘Plants maintain the ability to form lateral appendages throughout their life cycle and form leaves as the principal lateral appendages of the stem. Leaves initiate at the peripheral zone of the shoot apical meristem and then develop into flattened structures. In most plants, the leaf functions as a solar panel, where photosynthesis converts carbon dioxide and water into carbohydrates and oxygen. To produce structures that can optimally fulfill this function, plants precisely control the initiation, shape, and polarity of leaves. Moreover, leaf development is highly flexible but follows common themes with conserved regulatory mechanisms. Leaves may have evolved from lateral branches that are converted into determinate, flattened structures. Many other plant parts, such as floral organs, are considered specialized leaves, and thus leaf development underlies their morphogenesis. Here, we review recent advances in the understanding of how threedimensional leaf forms are established. We focus on how genes, phytohormones, and mechanical properties modulate leaf development, and discuss these factors in the context of leaf initiation, polarity establishment and maintenance, leaf flattening, and intercalary growth.
基金Publication of this paper is supported by the National Natural Science Foundation of China （30624808） and Science Publication Foundation of the Chinese Academy of Sciences.Acknowledgements We thank Xianhui Hou （Peking University） for helpful suggestions and valuable discussions.
文摘Leaf morphogenesis is strictly controlled not only by intrinsic genetic factors, such as transcriptional factors, but also by environmental cues, such as light, water and pathogens. Nevertheless, the molecular mechanism of how leaf morphogenesis is regulated by genetic programs and environmental cues is far from clear. Numerous series of events demonstrate that plant hormones, mostly small and simple molecules, play crucial roles in plant growth and development, and in responses of plants to environmental cues such as light. With more and more genetics and molecular evidence obtained from the model plant Arabidopsis, several fundamental aspects of leaf morphogenesis including the initiation of leaf primordia, the determination of leaf axes, the regulation of cell division and expansion in leaves have been gradually unveiled. Among these phytohormones, auxin is found to be essential in the regulation of leaf morphogenesis.
文摘Maca （Lepidium meyenii Walp, 2n = 8x = 64）, belonging to the Brassicaceae family, is an economic plant cultivated in the central Andes sierra in Peru （4000-4500 m）. Considering that the rapid uplift of the central Andes occurred 5-10 million years ago （Ma）, an evolutionary question arises regarding how plants such as maca acquire high-altitude adaptation within a short geological period. Here, we report the high-quality genome assembly of maca, in which two closely spaced maca-specific whole-genome duplications （WGDs; ~6.7 Ma） were identified. Comparative genomic analysis between maca and closely related Brassicaceae species revealed expansions of maca genes and gene families involved in abiotic stress response, hormone signaling pathway, and secondary metabolite biosynthesis via WGDs. The retention and subsequent functional divergence of many duplicated genes may account for the morphological and physiological changes （i.e., small leaf shape and self-fertility） in maca in a high-altitude environment. In addition, some duplicated maca genes were identified with functions in morphological adaptation （i.e., LEAF CURLING RESPONSIVENESS） and abiotic stress response （i.e., GL YClNE-RICH RNA-BINDING PROTEINS and DNA-DAMAGE-REPAIR/TOLERATION2） under positive selection. Collectively, the maca genome provides use- ful information to understand the important roles of WGDs in the high-altitude adaptation of plants in the Andes.
基金the National Natural Science Foundation of China(30640013).
文摘Floral morphogenesis and the development of Cercidiphyllumjaponicum Sieb. et Zucc. were observed by scanning electron microscopy （SEM）. The results showed that the pistillate inflorescences were congested spikes with the flowers arranged opposite. Great differences between the so-called ＂bract＂ and the vegetative leaf were observed both in morphogenesis and morphology. In morphogenesis, the ＂bract＂ primordium is crescent-shaped, truncated at the apex and not conduplicate, has no stipule primordium at the base but does have some inconspicuous teeth in the margin that are not glandular. The leaf primordium is triangular, cycloidal at the apex, conduplicate, has two stipule primordia at the base, has one gland-tooth at the apex occurring at first and some gland-teeth in the margin that occur later. In morphology, the ＂bract＂ is also different to the vegetative leaf in some characteristics that were also illustrated in the present paper. Based on the hypothesis that the bract is more similar to the vegetative leaf than the tepal, we considered that the so-called ＂bract＂ of C.japonicum might be the tepal of the pistillate flower in morphological nature. Therefore, each pistillate flower contains a tepal and a carpel. We did not find any trace of other floral organs in the morphogenesis of the pistillate flower. Therefore we considered that the unicarpellate status of extant Cercidiphyllum might be to highly reduce and advance characteristics that make the extant Cercidiphyllum isolated from both fossil Cercidiphyllum-like plants and its extant affinities.
基金This work was supported by grants from the National Natural Science Foundation of China(Grant Nos.31861143006,31901483 and 31770195)National Key Research and Development Program of China(Grant No.2016YFDO101801)Zhejiang Provincial‘Ten Thousand Talent Program’(Grant No.2018R52025).
文摘An ideal leaf shape is beneficial to the yield of rice.Molecular understanding of the leaf primordia and polarity establishment plays a significant role in exploring the genetic regulatory network of leaf morphogenesis.In recent years,researchers have cloned an array of coding genes and a few non-coding small RNAs involved in rice leaf development through regulating the development of leaf primordia,vascular bundles,sclerenchyma cells,bulliform cells,cell walls and epidermis cells.These genes and their interactions play critical roles in rice leaf development through the determination and regulatory role in gene expression,and their coordination with other genetic networks or signal pathways.But the relationship among these genes is poorly defined and the underlying network is still unclear.In this review,we introduced the regulatory pathways of leaf primordium development and leaf polarity establishment,mainly the relationship between cell development mechanism and leaf polarity establishment,focusing on how leaf tissue affects leaf shape.Hopefully,the regulation network reviewed here has immediate implications for future research and genomic design breeding.
文摘同源异型盒基因KNOX1(class I KNOTTED-like homeobox)广泛存在于植物中,具备调控和维持茎顶端分生组织活性的功能。近年来研究发现,KNOX1基因家族参与植物激素调控和各个器官的形态建成,尤其对植物花和叶的发育有着重要作用。本文介绍了KNOX1的表达模式,与植物激素的调控作用,在花和叶形态建成中的功能,并综述了拟南芥中KNOX1的相互作用因子及其功能,为进一步阐明KNOX1在植物发育中的分子机制提供参考。最后展望了未来KNOX1的研究方向及发展趋势。
基金support from Nanyang Technological University(grant no.M4082428)K.J.H.and C.H.acknowledge support from Nanyang Technological University under its Accelerating Creativity and Excellence(ACE)grant(grant no.NTU-ACE2020-07)+2 种基金supported by the Center for Engineering Mechano Biology,an National Science Foundation(NSF)Science and Technology Center,under grant agreement No.CMMI:15-48571supported by the U.S.Department of Energy(grant no.DE-FG2-84ER13179)support from the Ministry of Education-Singapore,under its Academic Research Fund Tier 1(RT11/20 and RG32/20).
文摘Plants produce a rich diversity of biological forms,and the diversity of leaves is especially notable.Mechanisms of leaf morphogenesis have been studied in the past two decades,with a growing focus on the interactive roles of mechanics in recent years.Growth of plant organs involves feedback by mechanical stress:growth induces stress,and stress affects growth and morphogenesis.Although much attention has been given to potential stress-sensing mechanisms and cellular responses,the mechanical principles guiding morphogenesis have not been well understood.Here we synthesize the overarching roles of mechanics and mechanical stress in multilevel and multiple stages of leaf morphogenesis,encompassing leaf primordium initiation,phyllotaxis and venation patterning,and the establishment of complex mature leaf shapes.Moreover,the roles of mechanics at multiscale levels,from subcellular cytoskeletal molecules to single cells to tissues at the organ scale,are articulated.By highlighting the role of mechanical buckling in the formation of three-dimensional leaf shapes,this review integrates the perspectives of mechanics and biology to provide broader insights into the mechanobiology of leaf morphogenesis.
