scholarly journals Gene Silencing of Argonaute5 Negatively Affects the Establishment of the Legume-Rhizobia Symbiosis

2017 ◽  
Author(s):  
Maria del Rocio Reyero-Saavedra ◽  
Zhenzhen Qiao ◽  
María del Socorro Sánchez-Correa ◽  
M. Enrique Díaz-Pineda ◽  
Jose L. Reyes ◽  
...  
Keyword(s):  
Common Bean ◽  
Control Plant ◽  
Potato Virus X ◽  
Systemic Resistance ◽  
Nodule Formation ◽  
Preferential Expression ◽  
Nuclear Factor Y ◽  
Microbe Interactions ◽  
Hair Curling ◽  
Root Hair Curling

The establishment of the symbiosis between legumes and nitrogen-fixing rhizobia is finely regulated at the transcriptional, posttranscriptional and posttranslational levels. Argonaute5 (AGO5), a protein involved in RNA silencing, is able to bind both viral RNAs and microRNAs to control plant-microbe interactions and plant physiology. For instance, AGO5 regulates the systemic resistance of Arabidopsis against Potato Virus X as well as the pigmentation of soybean (Glycine max) seeds. Here, we show that AGO5 is also playing a central role in legume nodulation based on its preferential expression in common bean (Phaseolus vulgaris) and soybean roots and nodules. We also report that the expression of AGO5 is induced after 1 hour of inoculation with rhizobia. Down-regulation of AGO5 gene in P. vulgaris and G. max causes diminished root hair curling, reduces nodule formation and interferes with the induction of three critical symbiotic genes: NUCLEAR FACTOR Y-B (NF-YB), NODULE INCEPTION (NIN) and FLOTILIN2 (FLOT2). Our findings provide evidence that the common bean and soybean AGO5 genes play an essential role in the establishment of the symbiosis with rhizobia in determinate legumes.

Rhizobial tRNA-derived small RNAs are signal molecules regulating plant nodulation

Science ◽  
2019 ◽  
Vol 365 (6456) ◽  
pp. 919-922 ◽  
Author(s):  
Bo Ren ◽  
Xutong Wang ◽  
Jingbo Duan ◽  
Jianxin Ma
Keyword(s):  
Small Rna ◽  
Nodule Formation ◽  
Signal Molecules ◽  
Rna Fragments ◽  
Bacterial Small Rna ◽  
Nodule Initiation ◽  
Hair Curling ◽  
Root Hair Curling ◽  
Host Genes ◽  
Short Tandem

Rhizobial infection and root nodule formation in legumes require recognition of signal molecules produced by the bacteria and their hosts. Here, we show that rhizobial transfer RNA (tRNA)-derived small RNA fragments (tRFs) are signal molecules that modulate host nodulation. Three families of rhizobial tRFs were confirmed to regulate host genes associated with nodule initiation and development through hijacking the host RNA-interference machinery that involves ARGONAUTE 1. Silencing individual tRFs with the use of short tandem target mimics or by overexpressing their targets represses root hair curling and nodule formation, whereas repressing these targets with artificial microRNAs identical to the respective tRFs or mutating these targets with CRISPR-Cas9 promotes nodulation. Our findings thus uncover a bacterial small RNA–mediated mechanism for prokaryote-eukaryote interaction and may pave the way for enhancing nodulation efficiency in legumes.

scholarly journals Host Specificity In The Root Hair "Curling Factor" of Rhizobium Spp.

1969 ◽  
Vol 22 (2) ◽  
pp. 413 ◽  
Author(s):  
Phaik Y Yao ◽  
JM Vincent
Keyword(s):  
Medicago Sativa ◽  
Host Specificity ◽  
Root Hair ◽  
Root Zone ◽  
Root Hairs ◽  
Degree Of Deformation ◽  
Medicago Sativa L ◽  
Rhizobium Spp ◽  
Hair Curling ◽  
Root Hair Curling

Thirty-eight cultures of rhizobia and 10 non-rhizobia growing in the root zone of clover (Trifolium glomeratum L.), 5 rhizobia and 3 non-rhizobia in that of lucerne (Medicago sativa L.), and 8 rhizobia in that ofSiratro (Phaseolus atropurpureus DO.) revealed a specific relationship between bacteria and host that determined the kind and degree of deformation of the root hairs.

scholarly journals Specific hypersensitive response-associated recognition of new apoplastic effectors fromCladosporium fulvumin wild tomato

2017 ◽  
Author(s):  
Carl H. Mesarich ◽  
Bilal Ökmen ◽  
Hanna Rovenich ◽  
Scott A. Griffiths ◽  
Changchun Wang ◽  
...  
Keyword(s):  
Hypersensitive Response ◽  
Expression System ◽  
Potato Virus X ◽  
Cladosporium Fulvum ◽  
In Planta ◽  
Antimicrobial Proteins ◽  
Wild Tomato ◽  
Microbe Interactions ◽  
Leaf Apoplast ◽  
Tomato Leaf Mould

ABSTRACTTomato leaf mould disease is caused by the biotrophic fungusCladosporium fulvum. During infection,C. fulvumproduces extracellular small secreted protein (SSP) effectors that function to promote colonization of the leaf apoplast. Resistance to the disease is governed byCfimmune receptor genes that encode receptor-like proteins (RLPs). These RLPs recognize specific SSP effectors to initiate a hypersensitive response (HR) that renders the pathogen avirulent.C. fulvumstrains capable of overcoming one or more of all clonedCfgenes have now emerged. To combat these strains, newCfgenes are required. An effectoromics approach was employed to identify wild tomato accessions carrying newCfgenes. Proteomics and transcriptome sequencing were first used to identify 70 apoplasticin planta-inducedC. fulvumSSPs. Based on sequence homology, 61 of these SSPs were novel or lacked known functional domains. Seven, however, had predicted structural homology to antimicrobial proteins, suggesting a possible role in mediating antagonistic microbe−microbe interactionsin planta. Wild tomato accessions were then screened for HR-associated recognition of 41 SSPs using thePotato virus X-based transient expression system. Nine SSPs were recognized by one or more accessions, suggesting that these plants carry newCfgenes available for incorporation into cultivated tomato.

scholarly journals Calcium/Calmodulin-Mediated Defense Signaling: What Is Looming on the Horizon for AtSR1/CAMTA3-Mediated Signaling in Plant Immunity

2022 ◽  
Vol 12 ◽  
Author(s):  
Peiguo Yuan ◽  
Kiwamu Tanaka ◽  
B. W. Poovaiah
Keyword(s):  
Transcription Factors ◽  
Plant Immunity ◽  
Control Plant ◽  
Plant Cells ◽  
Regulatory Mechanisms ◽  
Early Event ◽  
Gradual Change ◽  
Microbe Interactions ◽  
Immune Related Genes ◽  
Stressful Environments

Calcium (Ca2+) signaling in plant cells is an essential and early event during plant-microbe interactions. The recognition of microbe-derived molecules activates Ca2+ channels or Ca2+ pumps that trigger a transient increase in Ca2+ in the cytoplasm. The Ca2+ binding proteins (such as CBL, CPK, CaM, and CML), known as Ca2+ sensors, relay the Ca2+ signal into down-stream signaling events, e.g., activating transcription factors in the nucleus. For example, CaM and CML decode the Ca2+ signals to the CaM/CML-binding protein, especially CaM-binding transcription factors (AtSRs/CAMTAs), to induce the expressions of immune-related genes. In this review, we discuss the recent breakthroughs in down-stream Ca2+ signaling as a dynamic process, subjected to continuous variation and gradual change. AtSR1/CAMTA3 is a CaM-mediated transcription factor that represses plant immunity in non-stressful environments. Stress-triggered Ca2+ spikes impact the Ca2+-CaM-AtSR1 complex to control plant immune response. We also discuss other regulatory mechanisms in which Ca2+ signaling activates CPKs and MAPKs cascades followed by regulating the function of AtSR1 by changing its stability, phosphorylation status, and subcellular localization during plant defense.

scholarly journals Identification of miRNAs Involved in Bacillus velezensis FZB42-Activated Induced Systemic Resistance in Maize

2019 ◽  
Vol 20 (20) ◽  
pp. 5057 ◽  
Author(s):  
Shanshan Xie ◽  
Hengguo Yu ◽  
Enze Li ◽  
Yu Wang ◽  
Juan Liu ◽  
...  
Keyword(s):  
Defense Response ◽  
Target Genes ◽  
Induced Systemic Resistance ◽  
Systemic Resistance ◽  
Abiotic Stress Response ◽  
Bacillus Velezensis ◽  
Nuclear Factor Y ◽  
Network Analyses ◽  
Cis Element ◽  
Differentially Expressed Mirna

Bacillus velezensis FZB42 is able to activate induced systemic resistance (ISR) to enhance plant defense response against pathogen infections. Though the roles of microRNAs (miRNAs) in Bacillus-triggered ISR have been reported in Arabidopsis, the maize miRNAs responsible for the Bacillus-activated ISR process have not been discovered. To explore the maize miRNAs involved in ISR, maize miRNAs in response to FZB42 (ISR activating), FZB42△sfp△alss (deficient in triggering ISR), and a control for 12 h were sequenced. A total of 146 known miRNAs belonging to 30 miRNA families and 217 novel miRNAs were identified. Four miRNAs specifically repressed in FZB42-treatment were selected as candidate ISR-associated miRNAs. All of them contained at least one defense response-related cis-element, suggesting their potential roles in activating the ISR process. Interestingly, three of the four candidate ISR-associated miRNAs belong to the conserved miR169 family, which has previously been confirmed to play roles in abiotic stress response. Moreover, 52 mRNAs were predicted as potential targets of these candidate ISR-associated miRNAs through TargetFinder software and degradome sequencing. Gene Ontology (GO) and network analyses of target genes showed that these differentially expressed miRNA might participate in the ISR process by regulating nuclear factor Y transcription factor. This study is helpful in better understanding the regulatory roles of maize miRNAs in the Bacillus-activated ISR process.

Rhizobium nodulation genes involved in root hair curling (Hac) are functionally conserved

1985 ◽  
Vol 4 (2-3) ◽  
pp. 147-160 ◽  
Author(s):  
M. A. Djordjevic ◽  
P. R. Schofield ◽  
R. W. Ridge ◽  
N. A. Morrison ◽  
B. J. Bassam ◽  
...  
Keyword(s):  
Root Hair ◽  
Nodulation Genes ◽  
Hair Curling ◽  
Root Hair Curling ◽  
Rhizobium Nodulation

scholarly journals Annotation, phylogeny and expression analysis of the nuclear factor Y gene families in common bean (Phaseolus vulgaris)

2015 ◽  
Vol 5 ◽  
Author(s):  
Carolina Rípodas ◽  
Mélisse Castaingts ◽  
Joaquín Clúa ◽  
Flavio Blanco ◽  
María Eugenia Zanetti
Keyword(s):  
Phaseolus Vulgaris ◽  
Common Bean ◽  
Expression Analysis ◽  
Gene Families ◽  
Nuclear Factor ◽  
Nuclear Factor Y

scholarly journals Lotus japonicus NF-YA1 Plays an Essential Role During Nodule Differentiation and Targets Members of the SHI/STY Gene Family

2016 ◽  
Vol 29 (12) ◽  
pp. 950-964 ◽  
Author(s):  
Md Shakhawat Hossain ◽  
Arina Shrestha ◽  
Sihui Zhong ◽  
Mandana Miri ◽  
Ryan S. Austin ◽  
...  
Keyword(s):  
Gene Family ◽  
Lotus Japonicus ◽  
Cortical Cell ◽  
Plant Evolution ◽  
Nodule Formation ◽  
Functional Diversification ◽  
Nuclear Factor Y ◽  
Functional Analyses ◽  
Transcription Factor Gene Family ◽  
Selection Of

Legume plants engage in intimate relationships with rhizobial bacteria to form nitrogen-fixing nodules, root-derived organs that accommodate the microsymbiont. Members of the Nuclear Factor Y (NF-Y) gene family, which have undergone significant expansion and functional diversification during plant evolution, are essential for this symbiotic liaison. Acting in a partially redundant manner, NF-Y proteins were shown, previously, to regulate bacterial infection, including selection of a superior rhizobial strain, and to mediate nodule structure formation. However, the exact mechanism by which these transcriptional factors exert their symbiotic functions has remained elusive. By carrying out detailed functional analyses of Lotus japonicus mutants, we demonstrate that LjNF-YA1 becomes indispensable downstream from the initial cortical cell divisions but prior to nodule differentiation, including cell enlargement and vascular bundle formation. Three affiliates of the SHORT INTERNODES/STYLISH transcription factor gene family, called STY1, STY2, and STY3, are demonstrated to be among likely direct targets of LjNF-YA1, and our results point to their involvement in nodule formation.

Commonality of root nodulation signals and nitrogen assimilation in tropical grain legumes belonging to the tribe Phaseoleae.

2000 ◽  
Vol 27 (10) ◽  
pp. 885 ◽  
Author(s):  
Felix D. Dakora
Keyword(s):  
Common Bean ◽  
Root Exudate ◽  
Metabolic Response ◽  
Pigeon Pea ◽  
Grain Legumes ◽  
Bambara Groundnut ◽  
Nodule Formation ◽  
Macrotyloma Geocarpum ◽  
Glycine Max L ◽  
The Tropics

The tribe Phaseoleae (family Leguminosae) is home to many of the annual food legumes cultivated in the tropics. Cowpea (Vigna unguiculata (L.) Walp.), Bambara groundnut (Vigna subterranea (L.) Verdc.), Kersting’s bean (Macrotyloma geocarpum L.), mung bean (Vigna radiata (L.) Wilczek) and common bean (Phaseolus vulgaris L.), all belonging to subtribe Phaseolinae, and together with soybean (Glycine max (L.) Merr., subtribe Glycininae) and pigeon pea (Cajanus cajan L., subtribe Cajaninae), are important members of the tribe Phaseoleae. These legumes are unique in their use of identical root chemical molecules to induce the expression of nodulation genes in their respective homologous microsymbionts during nodule formation. Of those studied so far, common bean, soybean, Bambara groundnut, Kersting’s bean and cowpea all use the isoflavones daidzein, genistein and coumestrol as root exudate signals to induce the expression of nod genes in their rhizobial partners. Additionally, members of the Phaseoleae tribe are easily recognised on the basis of their tropical biogeographic origin, broad host nodulation habit, route of Rhizobium entry into roots, chemotaxonomy and use of a common isoflavone biosynthetic pathway, determinate nodulation phenotype and internal nodule anatomy, xylem composition and transportable solutes of fixed N, site of NO3– reduction and metabolic response of N2-fed plants to NO3– supply. These shared traits and their potential application for agriculture are discussed in this review.

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