<i>Rj4</i>, a Gene Controlling Nodulation Specificity in Soybeans, Encodes a Thaumatin-Like Protein But Not the One Previously Reported

Tang, Fang; Yang, Shengming; Liu, Jinge; Zhu, Hongyan

doi:10.1104/pp.15.01661

Cited by 112 publications

(78 citation statements)

References 27 publications

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“…Multiple reports have described the generation of somatic mutations using CRISPR/Cas9 in soya bean (Cai et al ., ; Du et al ., ; Jacobs et al ., ; Lowder et al ., ; Michno et al ., ; Tang et al ., ). To date however, few studies have demonstrated whole‐plant soya bean mutagenesis (Cai et al ., ; Li et al ., ).…”

Section: Introductionmentioning

confidence: 97%

CRISPR/Cas9 and TALENs generate heritable mutations for genes involved in small RNA processing of Glycine max and Medicago truncatula

Curtin

Xiong

Michno

et al. 2017

Plant Biotechnology Journal

131

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SummaryProcessing of double‐stranded RNA precursors into small RNAs is an essential regulator of gene expression in plant development and stress response. Small RNA processing requires the combined activity of a functionally diverse group of molecular components. However, in most of the plant species, there are insufficient mutant resources to functionally characterize each encoding gene. Here, mutations in loci encoding protein machinery involved in small RNA processing in soya bean and Medicago truncatula were generated using the CRISPR/Cas9 and TAL‐effector nuclease (TALEN) mutagenesis platforms. An efficient CRISPR/Cas9 reagent was used to create a bi‐allelic double mutant for the two soya bean paralogous Double‐stranded RNA‐binding2 (GmDrb2a and GmDrb2b) genes. These mutations, along with a CRISPR/Cas9‐generated mutation of the M. truncatula Hua enhancer1 (MtHen1) gene, were determined to be germ‐line transmissible. Furthermore, TALENs were used to generate a mutation within the soya bean Dicer‐like2 gene. CRISPR/Cas9 mutagenesis of the soya bean Dicer‐like3 gene and the GmHen1a gene was observed in the T0 generation, but these mutations failed to transmit to the T1 generation. The irregular transmission of induced mutations and the corresponding transgenes was investigated by whole‐genome sequencing to reveal a spectrum of non‐germ‐line‐targeted mutations and multiple transgene insertion events. Finally, a suite of combinatorial mutant plants were generated by combining the previously reported Gmdcl1a, Gmdcl1b and Gmdcl4b mutants with the Gmdrb2ab double mutant. Altogether, this study demonstrates the synergistic use of different genome engineering platforms to generate a collection of useful mutant plant lines for future study of small RNA processing in legume crops.

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Section: Introductionmentioning

confidence: 97%

CRISPR/Cas9 and TALENs generate heritable mutations for genes involved in small RNA processing of Glycine max and Medicago truncatula

Curtin

Xiong

Michno

et al. 2017

Plant Biotechnology Journal

131

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“…Incompatible interactions at initial stages of the association can block bacterial infection and nodule organogenesis. This incompatibility can be caused by failed Nod factor or exopolysaccharide recognition (6)(7)(8)(9) or by induced plant immune responses (9)(10)(11). Symbiotic incompatibility also takes place at later stages of nodule development, resulting in the formation of infected but nonfunctional nodules (12,13).…”

mentioning

confidence: 99%

Microsymbiont discrimination mediated by a host-secreted peptide in Medicago truncatula

Yang

Wang

Fedorova

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

107

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The legume-rhizobial symbiosis results in the formation of root nodules that provide an ecological niche for nitrogen-fixing bacteria. However, plant-bacteria genotypic interactions can lead to wide variation in nitrogen fixation efficiency, and it is not uncommon that a bacterial strain forms functional (Fix + ) nodules on one plant genotype but nonfunctional (Fix − ) nodules on another. Host genetic control of this specificity is unknown. We herein report the cloning of the Medicago truncatula NFS1 gene that regulates the fixation-level incompatibility with the microsymbiont Sinorhizobium meliloti Rm41. We show that NFS1 encodes a nodulespecific cysteine-rich (NCR) peptide. In contrast to the known role of NCR peptides as effectors of endosymbionts' differentiation to nitrogen-fixing bacteroids, we demonstrate that specific NCRs control discrimination against incompatible microsymbionts. NFS1 provokes bacterial cell death and early nodule senescence in an allele-specific and rhizobial strain-specific manner, and its function is dependent on host genetic background.legumes | nodulation | nitrogen fixation specificity | symbiosis persistence | NCR peptides P lants of the legume family can supply their own nitrogen needs through symbioses with nitrogen-fixing soil bacteria called rhizobia. This symbiotic interaction commences when the host perceives rhizobial lipo-chitooligosaccharides known as nodulation (Nod) factors and initiates development of nodule primordia that become infected by the rhizobia (1). Infection of most legumes, including the model legume Medicago truncatula, starts in root hairs and involves formation of plant-made tubular structures known as infection threads (2). Infection threads direct bacteria to these primordia, where the rhizobia are released into the cytoplasm of host cells. During this process, the bacteria become surrounded by a host membrane, and these membrane compartments containing rhizobium are named symbiosomes. Subsequently, the rhizobia differentiate into nitrogen-fixing bacteroids (3).The legume-rhizobial symbiosis shows a high level of specificity, occurring at both species and genotypic levels (4, 5). Incompatible interactions at initial stages of the association can block bacterial infection and nodule organogenesis. This incompatibility can be caused by failed Nod factor or exopolysaccharide recognition (6-9) or by induced plant immune responses (9-11). Symbiotic incompatibility also takes place at later stages of nodule development, resulting in the formation of infected but nonfunctional nodules (12,13). This latter situation is well-documented in the Medicago-Sinorhizobium symbiosis, in which the bacteria undergo terminal differentiation (14). We previously screened a core collection of Medicago accessions using multiple Sinorhizobium meliloti strains, evaluating many host-strain combinations (13). In that experiment, ∼40% of the plant-strain combinations produced small, white infected nodules that were defective in nitrogen fixation (Fix − ) whereas only ∼2% resulte...

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“…In addition to Nod factors, rhizobia also use secreted effectors or microbe-associated molecular patterns (MAMPs) such as surface polysaccharides to facilitate their invasion of the host (7,8). Therefore, effector-or MAMP-triggered plant immunity mediated by intracellular nucleotide binding/leucine-rich repeat receptors or plasma membrane-localized pattern recognition receptors also plays an important role in determining host range of rhizobia (9,10).…”

mentioning

confidence: 99%

Host-secreted antimicrobial peptide enforces symbiotic selectivity in Medicago truncatula

Wang

Yang

Liu

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

114

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Legumes engage in root nodule symbioses with nitrogen-fixing soil bacteria known as rhizobia. In nodule cells, bacteria are enclosed in membrane-bound vesicles called symbiosomes and differentiate into bacteroids that are capable of converting atmospheric nitrogen into ammonia. Bacteroid differentiation and prolonged intracellular survival are essential for development of functional nodules. However, in the Medicago truncatula-Sinorhizobium meliloti symbiosis, incompatibility between symbiotic partners frequently occurs, leading to the formation of infected nodules defective in nitrogen fixation (Fix − ). Here, we report the identification and cloning of the M. truncatula NFS2 gene that regulates this type of specificity pertaining to S. meliloti strain Rm41. We demonstrate that NFS2 encodes a nodule-specific cysteine-rich (NCR) peptide that acts to promote bacterial lysis after differentiation. The negative role of NFS2 in symbiosis is contingent on host genetic background and can be counteracted by other genes encoded by the host. This work extends the paradigm of NCR function to include the negative regulation of symbiotic persistence in host-strain interactions. Our data suggest that NCR peptides are host determinants of symbiotic specificity in M. truncatula and possibly in closely related legumes that form indeterminate nodules in which bacterial symbionts undergo terminal differentiation.legumes | rhizobial symbiosis | nitrogen fixation | symbiotic specificity | NCR peptides

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Rj4, a Gene Controlling Nodulation Specificity in Soybeans, Encodes a Thaumatin-Like Protein But Not the One Previously Reported

Cited by 112 publications

References 27 publications

CRISPR/Cas9 and TALENs generate heritable mutations for genes involved in small RNA processing of Glycine max and Medicago truncatula

CRISPR/Cas9 and TALENs generate heritable mutations for genes involved in small RNA processing of Glycine max and Medicago truncatula

Microsymbiont discrimination mediated by a host-secreted peptide in Medicago truncatula

Host-secreted antimicrobial peptide enforces symbiotic selectivity in Medicago truncatula

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