Arabidopsis nac1 transduces auxin signal downstream of tir1 to promote lateral root development qi xie,1 giovanna frugis,2 diana colgan,2 and namhai chua2,3 1laboratory of plant cell biology, institute of molecular agrobiology, national university of singapore, 117604 singapore. Agl21 was highly expressed in root, particularly in the root central cylinder and lateral root primordia. Auxin auxin promotes root initiation, root emergence and primary root elongation. Cleclavata1 signaling pathway modulates lateral root. While lateral root development is a traceable process along the primary root and different stages can be found along this longitudinal axis of time and development, root system architecture is complex and difficult to quantify.
Prh1 mediates arf7lbd dependent auxin signaling to. Here, we use the wellestablished model of lateral root development to directly test the hypothesis that the rate of auxininduced auxiaa turnover sets the pace for auxinregulated developmental events. Lateral root formation is inhibited at high sugar concentrations or high cn ratios malamy and ryan, 2001. Here, the pr1 homolog prh1 was identified as a novel target of both arf7 and. The precise developmental role and molecular regulation of lrp1 in root development remain to be understood. Free fulltext pdf articles from hundreds of disciplines, all in one place mirna164directed cleavage of zmnac1 confers lateral root development in maize zea mays l. The degree of root branching impacts the efficiency of water uptake, acquisition of nutrients and anchorage by plants. Nitrogen is critical for plant growth but must be acquired from the soil in reduced forms such as nitrate. Noncanonical auxin signaling regulates cell division.
Root architecture can be very important in plant productivity. In lateral root development in arabidopsis truyen ngoc quach dr. Hormonal regulation of lateral root development in. Nishizawac,d, nobuhiro tsutsumic, yoshiaki inukaib,e. Understanding the regulation of lateral root development is therefore of vital agronomic importance. Author summary in arabidopsis thaliana auxin response factor7 arf7mediated auxin signaling plays a key role in lateral roots lrs development. The presence of different types of roots in plant species. The development of lateral roots requires multiple mechanisms that act together for accurate.
A gainoffunction mutation in iaa28 suppresses lateral. Monomeric uvr8 inhibits auxin responses in the root. Legumes develop different types of lateral organs from their primary root, lateral roots and nodules, the latter depending on a symbiotic interaction with sinorhizobium meliloti. The branching of roots through progressive formation of lateral roots is a major determinant of root systems archi tecture to assist plants in water uptake. Acc increased auxininduced gene expression in the root apex, but decreased expression in regions where lateral roots form and reduced free iaa in whole roots. Pdf in both radish and arabidopsis, lateral root initiation involves a series of rapid divisions in pericycle cells located on the xylem radius of the. Pdf background the crucial role of roots in plant nutrition, and consequently in plant productivity, is a strong motivation to study the growth and. Plant organ development is important for adaptation to a changing environment. Atmyb93 is a novel negative regulator of lateral root. In soybean, a majority of genotypes increased lr number in response to water.
Genetic and physiological studies have revealed that plant hormones play key roles in lateral root formation. Celltocell communication during lateral root development. Relationship between growth substrate moisture variability and lateral root development. Here, the product of prh1, a pr1 homolog annotated previously as encoding a pathogenresponsive protein, was identified as a target of arf7. Nadph oxidase subunits atrbohd and atrbohf play pivotal roles in regulating growth, development and stress responses in arabidopsis. Within each cavity size, copper root pruning did not affect the general morphology of 1yearold seedlings. Cavity size and copper root pruning affect production and. Of the lateral root dry weight that elongated during the first year after planting, 33% more occurred in the upper 5 cm of soil when seedlings were treated with copper. Auxin regulates aquaporin function to facilitate lateral root.
The effects of acc on these transcripts and on lateral root development were still present in the tir1 mutant, suggesting independent signaling networks. Kinetic analysis of auxininduced transcription factor networks controlling lateral root development in arabidopsis thaliana by stacey reavis lundy a thesis submitted to the graduate faculty of wake forest university graduate school of arts and sciences in partial fulfillment of the requirements for the degree of master of science biology. However, their functions in root development are still poorly understood. Interestingly, atmyb93 expression is highly restricted to the few endodermal cells overlying developing lateral root primordia, suggesting that this transcriptional regulator might play a key role in mediating the effect of the endodermis on lateral root development. Melatonin enhances lateral root development in a dosedependent manner and acts synergistically with auxin. Given the fact that lateral root development is considered to be a broad recapitulation of equivalent processes in the primary root, we investigated whether shr plays a role in lrp development and, consequently, on global rsa. Drought stress negatively affects rice productivity due to the lack of water necessary for growth and development. Air lateral root pruning affects longleaf pine seedling root system morphology this article is part of a larger document. Smax1smxl2 regulate root and root hair development. Nov 16, 2014 nadph oxidase atrbohd an d atrbohf negatively modulate lateral root development by changing the peroxidase activity and increasing the local generation of superoxide in primary roots of arabidopsis in an auxinindependent manner. Representative images of ars representing shortest, intermediate, and longest total lr length for each of three moisture regimes control, dry, saturated 10 to 20.
Lateral root formation is a major determinant of root systems architecture. Atmyb93 mutants have faster lateral root developmental progression and enhanced lateral root densities, while atmyb93overexpressing lines display the opposite phenotype. Phytohormones have been shown to function in the control of these organogeneses. Pdf dissecting arabidopsis lateral root development. To investigate the role of melatonin on lateral root development, 4dayold col0 seedlings were grown vertically on half ms medium with various concentrations of melatonin 50 to 500.
Nov 22, 2019 strigolactones sls and their derivatives are plant hormones that have recently been identified as regulators of primary lateral root lr development. The simple organization of the root of arabidopsis thaliana allows the development of lateral root primordia to be characterized histologically. Fine control of aerenchyma and lateral root development through auxiaa and arfdependent auxin signaling takaki yamauchia,b,c,1, akihiro tanakaa, hiroki inahashia, naoko k. Rice wuschelrelated homeobox 3a oswox3a modulates auxin. Here, the pr1 homolog prh1 was identified as a novel target of both arf7 and lbds. In this study, we show that mizukussei1 miz1, which was identified originally as a regulator of hydrotropism, functions as a novel regulator of hormonally mediated lateral root development. Nadph oxidase atrbohd an d atrbohf negatively modulate lateral root development by changing the peroxidase activity and increasing the local generation of superoxide in primary roots of arabidopsis in an auxinindependent manner.
View the article pdf and any associated supplements and figures for a. Lateral root mutants to date, only a handful of mutants have been identified on the basis of their lateral root phenotype in arabidopsis. Interestingly, atmyb93 expression is highly restricted to the few endodermal cells overlying developing lateral root primordia, suggesting that this transcriptional regulator might play a key role in mediating the effect of the. Here we report that agl21, an agl17clade madsbox gene, plays a crucial role in lateral root development. Madsbox transcription factor agl21 regulates lateral root. A shared gene drives lateral root development and root. Nguyen, dissertation supervisor abstract nac cuc, ataf and nam transcription factors have been found to promote lateral root lr numbers in arabidopsis through the auxin signaling pathway. Oct 15, 2019 nevertheless, how auxin regulates cell division pattern during lateral root development remains elusive. Atmyb93 is a novel negative regulator of lateral root development in arabidopsis. However, related signaling pathways have not been identified in legumes. Due to the acropetal development of lateral roots, early stages can be traced back at more distal. Representative images of lr development representing shortest, intermediate, and longest total lr lengths for each of sr, pr, and lg stages are shown in figure 2. Theories concerning the evolutionary origins of legume root nodules range from them being highly modified stems or lateral roots 1 1, 2. We genetically dissected the role of kl and sl signalling in root and root hair development in arabidopsis seedlings and show that most root traits are regulated by kl and not by sl signaling.
There is strong evidence for an involvement of an auxinsignaling pathway in this organogenesis process. Many different factors are involved in the formation of lateral roots. Ethylene inhibits lateral root development, increases iaa. Auxin regulates aquaporin function to facilitate lateral. Previous studies have shown that the formation of root cortical aerenchyma rca can influence the development of lateral roots, which. Understanding root systems to improve, seedling quality. Lateral root primordium1 lrp1, a member of the short internodesstylish shisty family, was identified as an auxin. We report here on the signaling module composed of the clavata3 clv3embryo surrounding region cle peptide and clavata1 clv1 leucinerich repeat receptor kinase, which regulate lateral root lr development in arabidopsis thaliana upon changes in s availability. Our understanding of the mechanisms controlling lateral root development has progressed tremendously in recent years through research in the model plant arabidopsis thaliana arabidopsis. Organization and cell differentiation in lateral roots of. Nitrate regulation of lateral root and root hair development.
Pdf dissecting arabidopsis lateral root development tom. Dubrovsky and forde 2011 suggested a set of methods to analyze lateral root development quantitatively in arabidopsis. Sep 16, 2012 we profiled aquaporin gene expression during lateral root development at high temporal resolution that is, at every stage of lateral root development by microdissecting root bends every 6 h pgi. Arabidopsis nac1 transduces auxin signal downstream of. Sos3 mediates lateral root development under low salt stress.
Noncanonical auxin signaling regulates cell division pattern. Pdf the developmental plasticity of the root system represents a key adaptive trait enabling plants to cope with abiotic stresses such as. B numbers n 15 plants and diameters n 37 nodules of nodules formed under conditions supplemented with kno 3 15 dai. Putting the brakes on lateral root development 24 july 2019, by talia ogliore lateral roots branch out horizontally like fingers. Strigolactones sls and their derivatives are plant hormones that have recently been identified as regulators of primary lateral root lr development. Root systems can display variable architectures that contribute to survival strategies of plants. Lateral root and root hair development response to external nitrate. The phytohormone auxin fulfils multiple roles throughout lr development. Lateral root formation in plants involves the stimulation of mature pericycle cells to proliferate and redifferentiate to create a new organ. Air lateral root pruning affects longleaf pine seedling root system morphology. Characterization of lateral root development at the onset. We have divided the process of lateral root development into 8 stages defined by specific anatomical. Atrbohd and atrbohf negatively regulate lateral root.
The molecular and cellular basis of lateral root formation has been most extensively studied in the. These results suggest that regulation of proteins that mediate auxin transport creates local auxin maxima, which specify the location of lateral root development. A shared gene drives lateral root development and root nodule. The wuschel related homeobox protein wox7 regulates the sugar.
We cloned and characterized the expression of medicago. Atnac2 also promoted or inhibited downstream gene expressions. Lateral root development lrd in arabidopsis thaliana, lateral root initiation lri is hallmarked by coordinated asymmetric divisions in adjacent xylem pole pericycle cells. Here, we report that auxin activates mitogenactivated protein kinase mapk signaling via transmembrane kinases tmks to control cell division pattern during lateral root development. Prh1 mediates arf7lbd dependent auxin signaling to regulate. Uvr8 inhibits lateral root development via regulation of myb73myb77. The development of lateral roots in arabidopsis thaliana is strongly dependent on signaling directed by the auxin response factor7 arf7, which in turn activates lateral organ boundaries domain lbd transcription factors lbd16, 18, 29 and 33. Interplay of auxin and cytokinin in lateral root development mdpi. The wuschel related homeobox protein wox7 regulates the. Our understanding of the mechanisms controlling lateral root development has progressed tremendously in recent years through research in. Sos3 mediates lateral root development under low salt. Melatonin acts synergistically with auxin to promote lateral.
This branching of roots also contributes to water uptake, and facilitates the extraction of nutrients required for the growth and development of the plant. Nevertheless, how auxin regulates cell division pattern during lateral root development remains elusive. B light, uvr8 localizes to the nucleus and inhibits the dna. We profiled aquaporin gene expression during lateral root development at high temporal resolution that is, at every stage of lateral root development by microdissecting root. We identify atmyb93 as an interaction partner of the lateral root promoting arabidillo proteins. This branching of roots also contributes to water uptake, and facilitates the extraction of nutrients required for the growth and development of the plant many different factors are involved in the formation of lateral roots. The response of root architecture to phosphate p deficiency is critical in plant growth and development. Introduction the root system facilitates nutrient and water uptake and is consequently important for. A shared gene drives lateral root development and root nodule symbiosis pathways in lotus takashi soyano1,2,3,yoshikazu shimoda4, masayoshi kawaguchi1,2, makoto hayashi3,4 legumes develop root nodules in symbiosis with nitrogenfi xing rhizobial bacteria.
In general, root foraging is triggered by an uneven distribution. The sugar responsiveness of the wox7 promoter suggests that wox7 regulate lateral root formation in a sugardependent manner. The embryonic primary root arises via a stereotypic cell lineage, whereas lateral roots arise postembryonically from a differentiated tis sue, the pericycle. Lateral root formation involving cell division in both. A gainoffunction mutation in iaa28 suppresses lateral root development. Here, the product of prh1, a pr1 homolog annotated previously as encoding a pathogenresponsive protein, was identified as a. Atnac2, a transcription factor downstream of ethylene and. Lateral root formation in plants involves the stimulation of mature pericycle cells to. Similar to many developmental processes, it is strongly regulated by the plant hormone auxin. Lateral roots extend horizontally from the primary root radicle and serve to anchor the plant securely into the soil. Wox7 regulates the sugar response of lateral root development. We did this by generating transgenic plants expressing degradation rate variants of iaa14, a crucial determinant of lateral root initiation. Plant science a shared gene drives lateral root development and root nodule symbiosis pathways in lotus takashi soyano1,2,3,yoshikazu shimoda4, masayoshi kawaguchi1,2, makoto hayashi3,4 legumes develop root nodules in symbiosis with nitrogenfi xing rhizobial bacteria.
Further analysis to examine local auxin accumulation in these root cells in nal23 is necessary to. The lateral organ boundaries domain lbd transcription factors lbd16, lbd18 and lbd29 act downstream of arf7mediated auxin signaling to control lrs formation. A lateral root densities and primary root length n 15 plants of wild type, als18a, and nfya15 nfyb11 14dayold. A strigolactone signal inhibits secondary lateral root. Root branching through lateral root formation is an important component of the adaptability of the root system to its environment. Very little is known about how lateral root placement is regulated and about the signals and mechanisms that direct lateral root formation. Relationship between lateral root development and adventitious root stage. The main hormones intrinsic stimuli and respective pathways responsible for root architecture development include. Cytokinins cytokinins regulate root apical meristem size and promote lateral root elongation. Lateral root formation and the multiple roles of auxin journal of.
Nishizawac,d, nobuhiro tsutsumic, yoshiaki inukaib,e, and mikio nakazonoa,f,1 agraduate school of bioagricultural sciences, nagoya university, nagoya, 4648601 aichi, japan. Often this occurs through biological fixation whereby nitrogenfixing bacteria, such as rhizobia, live symbiotically in root nodules of legumes. The model plant arabidopsis thaliana possesses a tap root system, in which the primary root and lateral roots lrs are major architectural determinants. We report that shr is indeed a key regulator, controlling primary, lateral, and anchor. Air lateral root pruning affects longleaf pine seedling. Auxin signaling modulates lateral root primordium1 lrp1. Pdf lateral root formation is a major determinant of root systems architecture. There is evidence that auxin is synthesised by the nitrogen. Nac1 mediates auxin signaling to promote lateral root development.
However, whether sls mediate secondary lr production in rice oryza sativa l. While lateral root development is a traceable process along the primary root and different stages can be found along this longitudinal axis of time and development, root system architecture is complex and dif. The root systems of higher plants have evolved to be highly plastic, capable of recognizing and colonizing fertile soils. Ars classified as srs had 53% and 85% greater mean lr count than prs and lgs, respectively. The lateral root lr is a main component of both the tap. Auxin is a key regulator of plant root growth in response to p deficiency, but the. Mutations like alf4 and sur1 either abolish or exhibit an overproliferation of lateral roots, respectively 8,5,9. Lateral root formation and development play vital roles in driving plant root system architecture. Pdf formation of lateral roots is a two stage process researchgate. These results indicate that atnac2 may be a transcription factor incorporating the environmental and endogenous stimuli into the process of plant lateral root development. Introduction the root system facilitates nutrient and water uptake and is consequently important for plant growth and reproduction. The degree of root branching impacts the efficiency of water. We identify atmyb93 as an interaction partner of the lateralrootpromoting arabidillo proteins. The importance of studies on root morphology and development is discussed to improve seedling growth.
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