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 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.

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 Rhizobial NodL O-Acetyl Transferase and NodS N-Methyl Transferase Functionally Interfere in Production of Modified Nod Factors

2001 ◽  
Vol 183 (11) ◽  
pp. 3408-3416 ◽  
Author(s):  
Isabel M. López-Lara ◽  
Dimitris Kafetzopoulos ◽  
Herman P. Spaink ◽  
Jane E. Thomas-Oates
Keyword(s):  
Nodule Formation ◽  
Signal Molecules ◽  
Nod Factors ◽  
Rhizobium Tropici ◽  
Methyl Transferase ◽  
Mesorhizobium Loti ◽  
Methyl Group ◽  
Rhizobial Species ◽  
Acetyl Group

ABSTRACT The products of the rhizobial nodulation genes are involved in the biosynthesis of lipochitin oligosaccharides (LCOs), which are host-specific signal molecules required for nodule formation. The presence of an O-acetyl group on C-6 of the nonreducingN-acetylglucosamine residue of LCOs is due to the enzymatic activity of NodL. Here we show that transfer of the nodLgene into four rhizobial species that all normally produce LCOs that are not modified on C-6 of the nonreducing terminal residue results in production of LCOs, the majority of which have an acetyl residue substituted on C-6. Surprisingly, in transconjugant strains ofMesorhizobium loti, Rhizobium etli, and Rhizobium tropici carrying nodL, such acetylation of LCOs prevents the endogenous nodS-dependent transfer of theN-methyl group that is found as a substituent of the acylated nitrogen atom. To study this interference betweennodL and nodS, we have cloned thenodS gene of M. loti and used its product in in vitro experiments in combination with purified NodL protein. It has previously been shown that a chitooligosaccharide N deacetylated on the nonreducing terminus (the so-called NodBC metabolite) is the preferred substrate for NodS as well as for NodL. Here we show that the NodBC metabolite, acetylated by NodL, is not used by the NodS protein as a substrate while the NodL protein can acetylate the NodBC metabolite that has been methylated by NodS.

Molecular sieving polymer for DNA/RNA separation in capillary electrophoresis

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744094 ◽  
Author(s):  
Chenchen Liu ◽  
Yoshinori Yamaguchi ◽  
Xiaoming Dou
Keyword(s):  
Capillary Electrophoresis ◽  
Small Rna ◽  
Polymer Concentration ◽  
Migration Time ◽  
Migration Behavior ◽  
Molecular Weights ◽  
Rna Fragments ◽  
Molecular Sieving

In capillary polymer electrophoresis, the property of polymer sieving matrix dominates the migration behavior of DNA/RNA. We investigated the capillary electrophoresis of RNA ranging from 100 nt to 10,000 nt in polyacrylamide (PA) solutions with different molecular weights (Mw) and different concentrations. We observed that the resolution length (RSL) of RNA fragments was improved and the migration time was prolonged, when polymer concentration was increased. The resolution for small RNA fragments ([Formula: see text]1000 nt) was improved with the increase of polymer concentration, whereas the large ones ([Formula: see text]3000 nt) became inseparable. In addition, we estimated the smallest resolvable nucleotide length (Ls) by the plot of RSL against RNA size.

scholarly journals Degradation of Fungal MicroRNAs Triggered by Short Tandem Target Mimics Is via the Small-RNA-Degrading Nuclease

2019 ◽  
Vol 85 (9) ◽  
Author(s):  
Yulong Wang ◽  
Zhangxun Wang ◽  
Wenjing Yang ◽  
Xiangyun Xie ◽  
Haiyan Cheng ◽  
...  
Keyword(s):  
Small Rna ◽  
Target Genes ◽  
Rna Binding ◽  
Fungal Species ◽  
Metarhizium Robertsii ◽  
Content Type ◽  
Rna Molecules ◽  
Significant Difference ◽  
Pol Iii ◽  
Short Tandem

ABSTRACT MicroRNAs (miRNAs) have been recognized as sequence-specific regulators of the genome, transcriptome, and proteome in eukaryotes. However, the functions and working mechanisms of hundreds of fungal miRNA-like (miR-like) RNAs are obscure. Here, we report that a short tandem target mimic (STTM) triggered the degradation of several fungal miR-like RNAs in two different fungal species, Metarhizium robertsii and Aspergillus flavus, and that small-RNA-degrading nucleases (SDNs) were indispensable for such degradation. STTMs were most effective when the fungal polymerase II (Pol II) promoter was used for their expression, while the Pol III promoter was less effective. The length of the STTM spacer, approximately 48 to 96 nucleotides, and the number of miR-like RNA binding sites, from 2 to 4 copies, showed no significant difference in the degradation of miR-like RNAs. STTMs modulated the miR-like RNA expression levels in at least two different fungal species, which further impacted fungal asexual growth and sporulation. Further analysis showed that the degraded miR-like RNAs in STTM mutants led to the upregulation of potential target genes involved in fungal development and conidial production, which result in different phenotypes in these mutants. The STTM technology developed in this study is an effective and powerful tool for the functional dissection of fungal miR-like RNAs. IMPORTANCE The development and application of STTM technology to block miR-like RNAs in M. robertsii and A. flavus may allow for efficient generation of miR-like RNA mutants in various fungi, providing a powerful tool for functional genomics of small RNA molecules in fungi.

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
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