scholarly journals Molecular framework for TIR1/AFB-Aux/IAA-dependent auxin sensing controlling adventitious rooting in Arabidopsis

2019 ◽  
Author(s):  
Abdellah Lakehal ◽  
Salma Chaabouni ◽  
Emilie Cavel ◽  
Rozenn Le Hir ◽  
Alok Ranjan ◽  
...  
Keyword(s):  
Indole Acetic Acid ◽  
Root Formation ◽  
Adventitious Rooting ◽  
Adventitious Root Formation ◽  
Loss Of Function ◽  
Auxin Response ◽  
Genetic Studies ◽  
Auxin Signalling ◽  
Positive Regulators ◽  
Molecular Framework

ABSTRACTIn Arabidopsis thaliana, canonical auxin-dependent gene regulation is mediated by 23 transcription factors from the AUXIN RESPONSE FACTOR (ARF) family interacting with 29 auxin/indole acetic acid repressors (Aux/IAA), themselves forming coreceptor complexes with one of six TRANSPORT INHIBITOR1/AUXIN-SIGNALLING F-BOX (TIR1/AFB) PROTEINS. Different combinations of co-receptors drive specific sensing outputs, allowing auxin to control a myriad of processes. Considerable efforts have been made to discern the specificity of auxin action. However, owing to a lack of obvious phenotype in single loss-of-function mutants in Aux/IAA genes, most genetic studies have relied on gain-of-function mutants, which are highly pleiotropic. Using loss-of-function mutants, we show that three Aux/IAA proteins interact with ARF6 and/or ARF8, which we have previously shown to be positive regulators of AR formation upstream of jasmonate, and likely repress their activity. We also demonstrate that TIR1 and AFB2 are positive regulators of adventitious root formation and suggest a dual role for TIR1 in the control of JA biosynthesis and conjugation, as revealed by upregulation of several JA biosynthesis genes in the tir1-1 mutant. We propose that in the presence of auxin, TIR1 and AFB2 form specific sensing complexes with IAA6, IAA9 and/or IAA17 that modulate JA homeostasis to control AR initiation.

scholarly journals The Involvement of Ethylene in Calcium-Induced Adventitious Root Formation in Cucumber under Salt Stress

2019 ◽  
Vol 20 (5) ◽  
pp. 1047 ◽  
Author(s):  
Jian Yu ◽  
Lijuan Niu ◽  
Jihua Yu ◽  
Weibiao Liao ◽  
Jianming Xie ◽  
...  
Keyword(s):  
Salt Stress ◽  
Carboxylic Acid ◽  
Adventitious Root ◽  
Root Formation ◽  
Signal Transduction Pathway ◽  
Acc Oxidase ◽  
Adventitious Rooting ◽  
Adventitious Root Formation ◽  
Vital Role ◽  
Endogenous Ethylene

Calcium and ethylene are essential in plant growth and development. In this study, we investigated the effects of calcium and ethylene on adventitious root formation in cucumber explants under salt stress. The results revealed that 10 μM calcium chloride (CaCl2) or 0.1 μM ethrel (ethylene donor) treatment have a maximum biological effect on promoting the adventitious rooting in cucumber under salt stress. Meanwhile, we investigated that removal of ethylene suppressed calcium ion (Ca2+)-induced the formation of adventitious root under salt stress indicated that ethylene participates in this process. Moreover, the application of Ca2+ promoted the activities of 1-aminocyclopropane-l-carboxylic acid synthase (ACS) and ACC Oxidase (ACO), as well as the production of 1-aminocyclopropane-l-carboxylic acid (ACC) and ethylene under salt stress. Furthermore, we discovered that Ca2+ greatly up-regulated the expression level of CsACS3, CsACO1 and CsACO2 under salt stress. Meanwhile, Ca2+ significantly down-regulated CsETR1, CsETR2, CsERS, and CsCTR1, but positively up-regulated the expression of CsEIN2 and CsEIN3 under salt stress; however, the application of Ca2+ chelators or channel inhibitors could obviously reverse the effects of Ca2+ on the expression of the above genes. These results indicated that Ca2+ played a vital role in promoting the adventitious root development in cucumber under salt stress through regulating endogenous ethylene synthesis and activating the ethylene signal transduction pathway.

Effect of polar auxin transport and gibberellins on xylem formation in pine cuttings under adventitious rooting conditions

2020 ◽  
Vol 67 (1-2) ◽  
pp. 27-39 ◽  
Author(s):  
Alberto Pizarro ◽  
Carmen Díaz-Sala
Keyword(s):  
Adventitious Root ◽  
Root Formation ◽  
Auxin Transport ◽  
Adventitious Rooting ◽  
Adventitious Root Formation ◽  
Polar Auxin Transport ◽  
Root Induction ◽  
Xylem Differentiation ◽  
Xylem Formation ◽  
Hypocotyl Cuttings

Maturation-related decline of adventitious root formation is one of the major factors affecting adventitious rooting in forest tree species. We demonstrate that inhibition of polar auxin transport promoted cambium and xylem differentiation in rooting-competent hypocotyl cuttings from Pinus radiata under conditions of adventitious root formation. Treatments with bioactive gibberellins inhibited rooting while at the same time inducing both the differentiation of a continuous ring of cambium and xylem formation. Treatments with inhibitors of gibberellin biosynthesis did not affect the rooting response. The results demonstrate that xylem parenchyma and procambial cells at the xylem poles of rooting-competent hypocotyl cuttings after excision and under conditions of adventitious root induction become adventitious root meristems or xylem, depending on the directional auxin flow. Gibberellin may interact with this pathway, inducing xylem differentiation and inhibiting rooting. We conclude that modifications of auxin flow at the rooting sites, and the priming of cambial cells to differentiate into xylem during tree ageing, may be associated with the maturation-related decline of adventitious root formation.

scholarly journals Multiple AUX/IAA–ARF modules regulate lateral root formation: the role of Arabidopsis SHY2/IAA3-mediated auxin signalling

2012 ◽  
Vol 367 (1595) ◽  
pp. 1461-1468 ◽  
Author(s):  
Tatsuaki Goh ◽  
Hiroyuki Kasahara ◽  
Tetsuro Mimura ◽  
Yuji Kamiya ◽  
Hidehiro Fukaki
Keyword(s):  
Lateral Root ◽  
Target Gene ◽  
Root Formation ◽  
Auxin Response ◽  
Cell Specification ◽  
Asymmetric Cell Divisions ◽  
Auxin Signalling ◽  
Lateral Organ ◽  
Indole 3 Acetic Acid

In Arabidopsis thaliana , lateral root (LR) formation is regulated by multiple auxin/indole-3-acetic acid (Aux/IAA)–AUXIN RESPONSE FACTOR (ARF) modules: (i) the IAA28–ARFs module regulates LR founder cell specification; (ii) the SOLITARY-ROOT (SLR)/IAA14–ARF7–ARF19 module regulates nuclear migration and asymmetric cell divisions of the LR founder cells for LR initiation; and (iii) the BODENLOS/IAA12–MONOPTEROS/ARF5 module also regulates LR initiation and organogenesis. The number of Aux/IAA–ARF modules involved in LR formation remains unknown. In this study, we isolated the shy2-101 mutant, a gain-of-function allele of short hypocotyl2/suppressor of hy2 ( shy2 ) /iaa3 in the Columbia accession. We demonstrated that the shy2-101 mutation not only strongly inhibits LR primordium development and emergence but also significantly increases the number of LR initiation sites with the activation of LATERAL ORGAN BOUNDARIES-DOMAIN16/ASYMMETRIC LEAVES2-LIKE18 , a target gene of the SLR/IAA14–ARF7–ARF19 module. Genetic analysis revealed that enhanced LR initiation in shy2-101 depended on the SLR/IAA14–ARF7–ARF19 module. We also showed that the shy2 roots contain higher levels of endogenous IAA. These observations indicate that the SHY2/IAA3–ARF-signalling module regulates not only LR primordium development and emergence after SLR/IAA14–ARF7–ARF19 module-dependent LR initiation but also inhibits LR initiation by affecting auxin homeostasis, suggesting that multiple Aux/IAA–ARF modules cooperatively regulate the developmental steps during LR formation.

scholarly journals Mist Level Influences Vapor Pressure Deficit and Gas Exchange During Rooting of Juvenile Stem Cuttings of Loblolly Pine

HortScience ◽  
2005 ◽  
Vol 40 (5) ◽  
pp. 1448-1456 ◽  
Author(s):  
Anthony V. LeBude ◽  
Barry Goldfarb ◽  
Frank A. Blazich ◽  
John Frampton ◽  
Farrell C. Wise
Keyword(s):  
Vapor Pressure ◽  
Pinus Taeda ◽  
Loblolly Pine ◽  
Vapor Pressure Deficit ◽  
Root Formation ◽  
Net Photosynthesis ◽  
Adventitious Rooting ◽  
Adventitious Root Formation ◽  
Stem Cuttings ◽  
Ambient Conditions

Two experiments were conducted during which juvenile hardwood or softwood stem cuttings of loblolly pine (Pinus taeda L.) were rooted under six mist regimes in a polyethylene-covered greenhouse to investigate the effect of mist level on vapor pressure deficit (VPD) and cutting water potential (Ψcut), and to determine the relationships between these variables and rooting percentage. In addition, net photosynthesis at ambient conditions (Aambient) and stomatal conductance (gs) were measured in stem cuttings during adventitious root formation to determine their relationship to rooting percentage. Hardwood stem cuttings rooted ≥80% when mean daily VPD between 1000 and 1800 hr ranged from 0.60 to 0.85 kPa. Although rooting percentage was related to Ψcut, and Aambient was related to Ψcut, rooting percentage of softwood stem cuttings was not related to Aambient of stem cuttings. Using VPD as a control mechanism for mist application during adventitious rooting of stem cuttings of loblolly pine might increase rooting percentages across a variety of rooting environments.

Chromate induces adventitious root formation via auxin signalling and SOLITARY-ROOT/IAA14 gene function in Arabidopsis thaliana

BioMetals ◽  
2015 ◽  
Vol 28 (2) ◽  
pp. 353-365 ◽  
Author(s):  
José López-Bucio ◽  
Randy Ortiz-Castro ◽  
León Francisco Ruíz-Herrera ◽  
Consuelo Vargas Juárez ◽  
Fátima Hernández-Madrigal ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Gene Function ◽  
Adventitious Root ◽  
Root Formation ◽  
Adventitious Root Formation ◽  
Auxin Signalling

scholarly journals Some Urea Derivatives Positively Affect Adventitious Root Formation: Old Concepts and the State of the Art

Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 321 ◽  
Author(s):  
Ricci Ada ◽  
Rolli Enrico
Keyword(s):  
Adventitious Root ◽  
Root Formation ◽  
Developmental Process ◽  
Adventitious Rooting ◽  
Adventitious Root Formation ◽  
Point Of View ◽  
Urea Derivatives ◽  
Positive Effects ◽  
Differentiated Cells ◽  
Structure Activity

The success of vegetative propagation programmes strongly depends on adventitious rooting, a postembryonic developmental process whereby new roots can be induced from differentiated cells in positions where normally they do not arise. This auxin-dependent organogenesis has been studied at molecular, cellular, and developmental levels, and our knowledge of the process has improved in recent years. However, bioactive compounds that enhance adventitious root formation and possibly reduce undesirable auxinic side effects are still needed to ameliorate this process. From this point of view, our structure–activity relationship studies concerning urea derivatives revealed that some of them, more specifically, the N,N′-bis-(2,3-methylenedioxyphenyl)urea (2,3-MDPU), the N,N′-bis-(3,4-methylenedioxyphenyl)urea (3,4-MDPU), the 1,3-di(benzo[d]oxazol-5-yl)urea (5-BDPU), and the 1,3-di(benzo[d]oxazol-6-yl)urea (6-BDPU), constitute a category of adventitious rooting adjuvants. The results of our studies are presented here, in order either to highlight the positive effects of the supplementation of these urea derivatives, or to better understand the nature of their interaction with auxin.

scholarly journals Changes in Cutting Composition during Early Stages of Adventitious Rooting of Miniature Rose Altered by Inoculation with Arbuscular Mycorrhizal Fungi

2004 ◽  
Vol 129 (5) ◽  
pp. 624-634 ◽  
Author(s):  
C.F. Scagel
Keyword(s):  
Amino Acids ◽  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Adventitious Roots ◽  
Root Formation ◽  
Arbuscular Mycorrhizal ◽  
Adventitious Rooting ◽  
Adventitious Root Formation ◽  
Reducing Sugar ◽  
Amf Inoculation

Many changes in metabolism are known to occur during adventitious root formation, including changes in amino acids, proteins, and carbohydrates. The influence of arbuscular mycorrhizal fungi (AMF) on adventitious rooting of rose was tested by inoculating four cultivars with Glomus intraradices Schenck & Smith. Changes in cutting composition were measured during the initial stages of adventitious root formation. Although there were cultivar-specific differences in response, AMF inoculation generally increased the biomass and number of adventitious roots on cuttings before root colonization was detected. Application of rooting hormone increased this effect. Inoculation with AMF washings also increased the root biomass and number, but only when cuttings were treated with hormone. Changes in cutting composition in response to AMF were detected at 7 to 14 days. Differences in protein concentrations in response to AMF or hormone application were similar, while differences in amino acid and reducing sugar concentrations were not. Concentrations of proteins and amino acids in cuttings at the beginning of the experiment were positively correlated with adventitious rooting, while concentrations of reducing sugars and nonreducing sugars were not correlated with rooting. These results suggests that nitrogen-containing compounds play an important role in adventitious rooting, and that changes in amino acids associated with AMF inoculation were potentially different than those that occurred when cuttings were treated with rooting hormone alone. Carbohydrate concentrations in cuttings were not strongly related to initiation of adventitious roots, but reducing sugar may play a role in regulating part of the response of cuttings to AMF. The response of rose cuttings prior to colonization by G. intraradices suggests that AMF-plant signaling events occurred prior to rooting.

scholarly journals Differential Protein Analysis of Pecan Hardwood Cuttings

HortScience ◽  
2019 ◽  
Vol 54 (9) ◽  
pp. 1551-1557 ◽  
Author(s):  
Fan Cao ◽  
Xinwang Wang ◽  
Zhuangzhuang Liu ◽  
Yongrong Li ◽  
Fangren Peng
Keyword(s):  
Energy Metabolism ◽  
Adventitious Root ◽  
Stress Proteins ◽  
Root Formation ◽  
Signal Transmission ◽  
Adventitious Rooting ◽  
Adventitious Root Formation ◽  
Differentially Expressed Proteins ◽  
Differential Protein ◽  
Related Proteins

Pecan cuttings are difficult for rooting. This study describes the pecan hardwood rooting process based on anatomic characteristics to understand root formation mechanisms of pecan cuttings. The expressed proteins of different periods during the adventitious rooting process of pecan seedling hardwood cuttings were identified and analyzed to evaluate the rooting mechanism. The expressed proteins of pecan cutting seedlings were also compared with other cultivar cuttings during the rooting period. Pecan seedling cuttings were developed at different air and substrate temperatures to induce root formation. Adventitious root formation of pecan hardwood cuttings was described, and the phloem at the base of the prepared cuttings was selected as the sample for the differential protein analysis. The results showed that adventitious root formation of pecan hardwood cuttings was the only product of callus differentiation, which originated from the cells of the cambium or vascular ray parenchyma. Such adventitious root primordia were developed from those calluses that formed the regenerative structure, and the expressed proteins during the adventitious rooting of pecan hardwood cutting were identified and analyzed by matrix-assisted laser desorption ionization–time of flight–mass spectrometry (MALDI-TOF-MS) to evaluate the rooting mechanism. Eight differentially expressed proteins were found in the rooting periods, and 15 differential proteins were found by comparing pecan cutting types, which were analyzed by peptide mass fingerprinting homology. The results show that the primordial cells were differentiated from the meristematic cells. Furthermore, the differentially expressed proteins contained energy metabolism proteins, adversity stress proteins, and signal transmission proteins. The energy metabolism-related proteins were adenosine triphosphate (ATP) synthase, photosynthesis-related proteins, and enolase. The adversity-stress proteins containing heat shock-related proteins and signal transmission proteins were mainly cytochrome enzymes and heme-binding proteins. Adventitious root formation of pecan cultivar hardwood cuttings was difficult. More trials should be performed from the potential aspects of high defensive protection and phloem morphologic structure.

Differential growth of Spartina densiflora populations under saline flooding is related to adventitious root formation and innate root ion regulation

2016 ◽  
Vol 43 (1) ◽  
pp. 52 ◽  
Author(s):  
Carla E. Di Bella ◽  
Agustín A. Grimoldi ◽  
María S. Rossi Lopardo ◽  
Francisco J. Escaray ◽  
Edmundo L. Ploschuk ◽  
...  
Keyword(s):  
Salt Marshes ◽  
Adventitious Root ◽  
Root Formation ◽  
Adventitious Rooting ◽  
Adventitious Root Formation ◽  
Superior Performance ◽  
Differential Growth ◽  
Ion Regulation ◽  
Aerenchyma Formation ◽  
Spartina Densiflora

Global change anticipates scenarios of sea level rise that would provoke long lasting floods, especially in lowland areas of salt marshes. Our aim was to evaluate the morpho-physiological adjustment ability to deal with continuous saline flooding of Spartina densiflora Brogn. plants from lowlands and uplands along a subtle topographical gradient (0.2 m differential altitude). Plants from both origins were subjected to continuous saline flooding (300 mM NaCl) for 35 days. Responses associated to adventitious rooting, aerenchyma formation, concentration of Na+, K+ and Cl– in roots and shoots tissues, tillering and growth were assessed. Root responses differentiated populations given that lowland plants showed higher ability for adventitious root formation and innate superior root ion regulation than upland plants. High constitutive K+ concentration plus high Na+ exclusion in root tissues led to significant low values of Na+ : K+ ratios in lowland plants. Better root functioning was, in turn, related with more consistent shoot performance as lowland plants maintained plant tiller number and shoot relative growth rate unaltered while upland plants decreased both parameters by 35 and 18%, respectively, when in saline flooding. The superior performance of lowland plants indicates that locally adapted populations can be promoted in salt marsh habitats with subtle differences at topographic level.

scholarly journals What Makes Adventitious Roots?

Plants ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 240 ◽  
Author(s):  
Gonin ◽  
Bergougnoux ◽  
Nguyen ◽  
Gantet ◽  
Champion
Keyword(s):  
Root System ◽  
Adventitious Root ◽  
Adventitious Roots ◽  
Root Formation ◽  
Primary Root ◽  
Adventitious Rooting ◽  
Adventitious Root Formation ◽  
Terrestrial Environment ◽  
Root Types ◽  
Embryonic Root

The spermatophyte root system is composed of a primary root that develops from an embryonically formed root meristem, and of different post-embryonic root types: lateral and adventitious roots. Adventitious roots, arising from the stem of the plants, are the main component of the mature root system of many plants. Their development can also be induced in response to adverse environmental conditions or stresses. Here, in this review, we report on the morphological and functional diversity of adventitious roots and their origin. The hormonal and molecular regulation of the constitutive and inducible adventitious root initiation and development is discussed. Recent data confirmed the crucial role of the auxin/cytokinin balance in adventitious rooting. Nevertheless, other hormones must be considered. At the genetic level, adventitious root formation integrates the transduction of external signals, as well as a core auxin-regulated developmental pathway that is shared with lateral root formation. The knowledge acquired from adventitious root development opens new perspectives to improve micropropagation by cutting in recalcitrant species, root system architecture of crops such as cereals, and to understand how plants adapted during evolution to the terrestrial environment by producing different post-embryonic root types.

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