Trichomes serve as a physical barrier on plant surfaces against many biotic and abiotic stresses, playing an important role in plant growth and development. Genetic diversity is all the different genes contained in all the living species, including individual plants, animals, fungi, and microorganisms. Cell differentiation requires that undifferentiated cells must be chosen before becoming committed to a specified cell. Secreting glandular plant trichome types which accumulate. In this species, trichomes have a typical unicellular structure and their origin from the epidermis comprises three successive phases. Great diversity exists in the morphology ofglandular trichomes at the organ, cellular, and subcellular levels 6. Some of the epidermal cells of most plants grow out in the form of hairs or trichomes.
Narayana 1979 suggested that trichomes can be a diagnostic character in vernonia schreb whereas wagner et al. Horner1, department of genetics, development and cell biology and microscopy and nanoimaging facility, iowa state university, ames, iowa 500111020, u. We report here the identification of ntm1like8 ntl8, a membraneassociated nac transcription factor, as a novel regulator of trichome formation in arabidopsis arabidopsis thaliana. Leaf trichome formation and plant resistance to herbivory.
Plants produce a myriad of taxonomically restricted specialized metabolites. Early development of leaf trichomes is associated with. Wilhelm barthlott, a sabine wiersch, a zdravko colic, a kerstin koch a a neesinstitute for biodiversity of plants, rheinische friedrichwilhelms university of bonn, meckenheimer allee 170, d53115 bonn, germany. The genes controling trichome formation are generally a class of myb transcription factors in arabidopsis 31, whereas a hdzip protein, woolly wo that interacts with cyclin b2, plays an essential role for trichome formation and embryonic development in tomato. Current understanding of trichome development is largely based on studies of mutants of arabidopsis thaliana, which have revealed the importance of over 40 genes that regulate trichome development schwab et al. The current work revealed that myb82 and gl1 can form homodimers or heterodimers at the nterminal r2r3myb domain. The mutations helped to define regulatory processes in trichome development. Mutations in either gene prevent the initiation of most trichomes. Molecular genetic analyses using mutants have demonstrated that the differentiation of trichomes and root hair.
Distinct relationships between glabra2 and single repeat. To explore the morphology, structure and ontogeny of vitis trichomes, we investigated the diversity and distribution of trichomes in 34 species of vitis. One clade includes gl1, atmyb23, ghmyb109 and gamyb2 proteins, all from the rosids. Trichome diversity in the subtribe leiboldiinae vernonieae. Horner1, department of genetics, development and cell biology and microscopy and nanoimaging facility, iowa state university. Trichome, as a protective barrier against natural hazards, plays an indispensable role in resisting ultraviolet radiation, pathogen invasion, herbivores feeding and water excessive transpiration during the process of plant growth and development. The trichome sits on top of a single basal cell, whose diameter is slightly larger than that of the stalk cell fig. Classification of fruit trichomes in cucumber and effects. Jul 19, 2011 trichomes are universal biological structures originating from the aerial epidermis, which serve as an excellent model to study plant differentiation at the cell level. Trichome density and its protective potential against.
Odowd and wilson 1989 hypothesized that such trichomes in leaf domatia function to. The systematic implication of flavonoids secretedby plants. Alongside this investigation, the trichome macrohair density was evaluated in the same plants to determine whether trichome density is associated with plant resistance. Morphology, structure, and ontogeny of trichomes of the.
Two genes that play an essential role in the initiation of trichome development are gl1 and ttg. Two main types of trichomes in vitis are documented. Progress on trichome development regulated by phytohormone. Although the pathway regulating trichome formation in the rosids has been well characterized, only very recently a few genes were identified for trichome initiation in the asterids. Trichome development have provided a best model to explore the mechanisms that underlie the patterned assignment of cell fates during development in plants. A contradictory phenomenon is the observation that overexpression of positive regulators of trichome development, gl1 and myb23, as well as myb82, often cause trichome number reductions larkin et al. Flavonoids are ubiquitous plant aromatic specialized metabolites found in a variety of cell types and organs. The nam, ataf12, and cuc nac are plantspecific transcription factors that regulate multiple aspects of plant growth and development and plant response to environmental stimuli. A genetic regulatory network in the development of. Glandular trichome diversity on leaves of lippia origanoides. Jan 01, 2004 recent studies of trichome differentiation and development. Trichomes also called hairs play wellrecognized roles in defense against insect herbivores, forming a physical barrier that obstructs insect movement and mediating chemical defenses. The view that the induction mechanisms controlling trichome formation in these different species are analogous rather than homologous is supported by the phylogenetic tree of gl1like myb proteins and mixtalike proteins, which shows that they fall into different evolutionary lineages clades figure 3a. In all cases, trichome density and the relative quantities of ultraviolet radiation absorbing phenolic constituents expressed on a leaf area basis declined.
Functional diversity of r3 singlerepeat genes in trichome development article pdf available in development 69. Classification of trichome types within species of the water fern salvinia, and ontogeny of the eggbeater trichomes. The variability of such networks determines the diversity of organ forms and functions in plants and animals 1, 2. The industrial uses of some trichome secretions and their potential as a defense barrier, for example against arthropod pests, has spurred research into the biosynthesis pathways. In addition, the glabrous rice 1glr1, which encodes a wuslike homeobox gene. Trichomes may be unicellular or multicellular and some plants such as arabidopsis thaliana may also have branches, according to the. Ecosystem diversity is all the different habitats, biological communities and.
Glandular trichome diversity on leaves of lippia origanoides and lippia stachyoides verbenaceae. An exposition on trichome development and cell shape with a. Trichome development in arabidopsis thaliana is a wellcharacterized model for the study of plant cell differentiation. Genetic basis for glandular trichome formation in cotton. Specialized trichome cells are useful as a model for. However, little is known on how enhanced trichome density would impinge on leaf photosynthesis, gas exchange and energy balance. An exposition on trichome development and cell shape with. In recent years, new genes related to trichome development in different plants have been isolated, for great strides in the understanding of. Trichome and root hair patterning are governed by a conserved cassette of bhlh and myb factors, the wd40 protein ttg1, and six singlerepeat myb r3 factors that are thought to counteract them. Luiz ricardo dos santos tozin, a shelly favorito carvalho, a silvia rodrigues machado, b tatiane maria rodrigues b. Our knowledge about this developmental process is still limited, but genes controlling glandular trichome initiation and. Trichome diversity in vegetative and reproductive structures of species from the subtribe leiboldiinae vernonieae, asteraceae are described and illustrated.
In advances in botanical research incorporating advances in plant pathology, vol. In recent years, new genes related to trichome development in different plants have been isolated, for great strides in the understanding of molecular mechanisms underlying trichome development and regulation. Functional diversity of r3 singlerepeat genes in trichome. Original article the lanata trichome mutation increases. In keeping with the myriad functions carried out by plants, their component cells display an amazing diversity of shapes and sizes. The eglandular trichomes were further subdivided into unicellular papillae, conical, and filiform and multicellular flagelliform. The genetic, molecular and cellbiological analysis of trichome development has revealed only a few trichome specific processes, as most developmental steps involve the regulation of general. Trichomes are widely distributed on surfaces of different organs in the grape genus vitis and are of taxonomic utility. In recent years, the singlecelled, branched, aerial epidermal tri. Myb82 functions in regulation of trichome development in.
Because trichomes and root hairs are easily accessible, particularly in the model plant, their development has become a wellstudied model of cell differentiation and growth. Trichome metabolites were analyzed by liquid chromatographytime of flightmass spectrometry, revealing the presence of at least 34 structurally diverse acylsucroses and two acylglucoses. The variability of such networks determines the diversity of organ forms and functions in plants and animals 1. Trichomes are one of the most useful anatomical characters to be used in angiosperm taxonomy. Trichomes of tomato and other nightshade family plants produce structurally diverse protective compounds termed acylsugars. Our knowledge about this developmental process is still limited, but genes controlling glandular trichome initiation and morphogenesis have recently been identified.
They may be unicellular or multicellular and occur in various forms. Information about trichomes diversity and distribution of the family caryophyllaceae is rare and the present work is intended to fill this knowledge lacuna. Updates on molecular mechanisms in the development of. A single epidermal cell differentiates into a unicellular trichome. Previous work has compared multiple species differing in trichome. Changes in leaf trichomes and epicuticular flavonoids. The development of type vi glandular trichomes in the. They may be found singly or less frequently in groups. Plant trichomes are outgrowths developed from an epidermal pavement cells of leaves and other organs. In addition, trichomes can act as a mechanosensory switch, transducing mechanical stimuli e. A regulatory gene induces trichome formation and embryo.
Based on scanning electron microscopy, we identified two main trichome types, glandular and eglandular. Diversification of the etc3 gene has occurred at the. This study summarizes molecular mechanisms in trichome development and provides a detailed comparison of the similarities and differences between arabidopsis and cotton, analyses the possible reasons for the discrepancy in identification of regulators, and raises future questions and foci for understanding trichome development in more detail. Studies showed that gl3 can activate frc4 to affect trichome branching 21,49.
Trichome development in arabidopsis thaliana has become a wellstudied model system because of the availability of several mutants with defects in the initiation and development of these structures. To understand the processes of development and evolution of living organisms, the gene regulatory networks, or grns have to be taken into account. The identification of genes controlling glandular trichome development is of high interest to understand how plants produce specialized metabolites. The results in this report support the hypothesis that trichomes develop earlier which leads or facilities more resistance against chewing damage by s. A large number of mutations that affect trichome development were identified in several mutagenesis screens 5,6. This diversity is expressed between species but also within species or even individual plants. Advances in botanical research vol 31, pages 11 2000. A genetic regulatory network in the development of trichomes. Research open access the evolution of gene regulatory. Molecular mechanism and physiological function of trichome. Trichome diversity and development article in advances in botanical research 31. Finally, the process is amenable to genetic analysis because many mutations that affect trichome differentiation do not alter other aspects of plant development. Thiswill be followed bysections whichconsider ourpresent.
Allelespecific interactions between ttg and gl1 during. The genetic network regulating trichome development has been. The industrial uses of some trichome secretions and their potential as a defense barrier, for example against arthropod pests, has spurred research into the biosynthesis pathways that lead to these specialized metabolites. The fruit trichomes or fruit spines of cucumber, cucumis sativus l. The gl1 gene encodes a myb related transcription factor.
The genetic, molecular and cellbiological analysis of trichome development has revealed only a few trichomespecific processes, as most developmental steps involve the regulation of general. But the presence of furrows at earlier stages of development. Trichome density and the capacity of leaf hairs to protect underlying tissues against ultravioletb radiation damage were assessed during leaf development in three tree species. Methylated flavonoids are detected in secreting glandular trichomes of various solanum species, including the cultivated tomato solanum lycopersicum. In this work we focus on the singlerepeat r3 factor etc3 and show that its major role is in the regulation of trichome density in a redundant manner. Glandular trichome morphology and development glandular trichome morphology has been described in a large number of plant species and this abundant literature highlights their tremendous diversity of shape and size 12. In this study, acylsugar diversity was assessed for 80 accessions of the wild tomato species solanum habrochaites from throughout the andes mountains. Oct 25, 2019 tomato, with its eight distinct types of trichomes, is particularly well suited to study not only the presence and development of different types of trichomes, but also complex traits such as trichome density and the diversity of different trichomes on different tissues or organs, such as the stem and the adaxial and abaxial sides of leaves.
The development of plants, like all multicellular eukaryotes, lies on the appropriate differentiation of distinct cell types. This could also indicate that trichome formation is constitutive and is not induced by the presence of associated mites that usually occupy the chambers of open domatia. They vary considerably in morphology, location, ability to secrete and mode of secretion, and different types of trichome can be produced by the same plant. Trichomes originate from epidermal cells and can be classified as either glandular or nonglandular. The function and structural diversity of trichomes are intimately related, a relationship that this is explored in this thesis. Striking natural diversity in glandular trichome acylsugar. This work intends to illustrate nonglandular leaf trichome diversity in lychnophorinae and discuss this diversity in the light of the subtribes taxonomy. Trichomes are unicellular or multicellular appendages that originate from cells of the aerial epidermis. This diversityand our ability to correlate genotype with phenotypemakes the evolution of these ecologically and medicinally important compounds interesting and experimentally tractable. Species diversity is all the different species, as well as the differences within and between different species. Trichomes and chemical composition of the volatile oil of. Functional diversity of r3 singlerepeat genes in trichome development katja wester 1, simona digiuni 1, florian geier 2, jens timmer 3, christian fleck and martin hulskamp 1, trichome and root hair patterning are governed by a conserved cassette of bhlh and myb factors, the wd40 protein ttg1, and six. In recent years, many scientists have shifted the focus on plant developmental biology from the organization.
What types of regulatory networks are involved in defining the form of a trichome is visited as well, setting the stage for deeper studies into arabidopsis trichome development. The dynamic genetichormonal regulatory network controlling. This diversity occurs in plants which are lowerlevel accumulators trichome development on soybean and related glycine gynoecia r. Trichomes and root hairs differentiate from epidermal cells in the aerial tissues and roots, respectively. Therefore, gl2 and single myb transcription factors have opposing roles in trichome and root hair development. Classification of trichome types within species of the. Harnessing plant trichome biochemistry for the production of. Second, this differentiation occurs in a nonrandom pattern on the plant surface. Cucumber fruit trichomes could be classified into eight types. Unlike trichome density, the total number of glandular trichomes per leaf did not change during leaf development in any of the birch taxa studied f 5,30 23, p 0065, although it varied significantly among taxa f 2,6 157, p 0004 and between leaf sides depending on. Ntl8 regulates trichome formation in arabidopsis by. Tomato, with its eight distinct types of trichomes, is particularly well suited to study not only the presence and development of different types of trichomes, but also complex traits such as trichome density and the diversity of different trichomes on different tissues or organs, such as the stem and the adaxial and abaxial sides of leaves.
1401 1210 1333 1183 488 1193 386 798 1033 1457 1 28 1470 419 114 797 357 244 540 291 920 1654 636 1468 1111 600 1213 586 442 1226 760 210