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Results for “Plant Biology”

Search indexed bioRxiv preprints in genomics, neuroscience, cell biology and bioinformatics. Read source abstracts and check manuscript versions; preprints are not peer reviewed.

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At least 73 records · Page 4Linked to original sources

bioRxiv2013

ROS accumulation in cotton ovule epidermal cells is necessary for fiber initiation

Cotton (Gossypium hirsutum) fiber, an extremely elongated and thickened single cell of the seed epidermis, is the worlds most important natural and economical textile fiber. Unlike Arabidopsis leaf trichomes, fiber initials are randomly developed and frequently form in adjacent seed epidermal cells and follow no apparent pattern. Numerous publications suggested cotton fiber development shares a similar mechanism with Arabidopsis leaf trichome development. Here we show that H2O2 accumulation in cotton ovule epidermal cells by NBT staining ovules at different development stages between TM1 and N1n2, a lintless-fuzzless doubled mutant originated from TM1. In contrast, Arabidopsis and cotton leaf trichomes do not show H2O2 content. By adding DPI (H2O2 inhibitor) and SHAM (H2O2 activator) in vitro ovule cultures, we show fiber initiation directly involves with H2O2 accumulation. We propose that the directional accumulation of H2O2 in cotton ovule epidermal cell is the drive for fiber initiation, elongation.

Plant Biology↗

bioRxiv2013

An XA21-Associated Kinase (OsSERK2) regulates immunity mediated by the XA21 and XA3 immune receptors

The rice XA21 immune receptor kinase and the structurally related XA3 receptor, confer immunity to Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of bacterial leaf blight. Here we report the isolation of OsSERK2 (rice somatic embryogenesis receptor kinase 2) and demonstrate that OsSERK2 positively regulates immunity mediated by XA21 and XA3 as well as the rice immune receptor FLS2 (OsFLS2). Rice plants silenced for OsSerk2 display altered morphology and reduced sensitivity to the hormone brassinolide. OsSERK2 interacts with the intracellular domains of each immune receptor in the yeast-two-hybrid system in a kinase activity dependent manner. OsSERK2 undergoes bidirectional trans-phosphorylation with XA21 in vitro and forms a constitutive complex with XA21 in vivo. These results demonstrate an essential role for OsSERK2 in the function of three rice immune receptors and suggest that direct interaction with the rice immune receptors is critical for their function. Taken together, our findings suggest that the mechanism of OsSERK2-meditated regulation of rice XA21, XA3 and FLS2 differs from that of AtSERK3/BAK1-mediated regulation of Arabidopsis FLS2 and EFR.

Plant Biology↗

bioRxiv2013

A conserved oomycete CRN effector targets and modulates tomato TCP14-2 to enhance virulence

Phytophthora spp. secrete vast arrays of effector molecules upon infection. A main class of intracellular effectors are the CRNs. They are translocated into the host cell and specifically localise to the nucleus where they are thought to perturb many different cellular processes. Although CRN proteins have been implicated as effectors, direct evidence of CRN mediated perturbation of host processes has been lacking. Here we show that a conserved CRN effector from P. capsici directly binds to tomato transcription factor SlTCP14-2. Previous studies in Arabidopsis thaliana have revealed that transcription factor TCP14 may be key immune signalling protein, targeted by effectors from divergent species. We extend on our understanding of TCP targeting by pathogen effectors by showing that the P. capsici effector CRN12_997 binds to SlTCP14-2 in plants. SlTCP14-2 over-expression enhances immunity to P. capsici, a phenotypic outcome that can be abolished by co-expression of CRN12_997.\n\nWe show that in the presence of CRN12_997, SlTCP14-2 association with nuclear chromatin is diminished, resulting in altered SlTCP14 subnuclear localisation. These results suggest that CRN12_997 prevents SlTCP14 from positively regulating defence against P. capsici. Our work demonstrates a direct interaction between an oomycete CRN and a host target required for suppression of immunity. Collectively, our results hint at a virulence strategy that is conserved within the oomycetes and may allow engineering of resistance to a wide range of crop pathogens.

Plant Biology↗

bioRxiv2013

DCL1, a Protein that Produces Plant MicroRNA, Coordinates Meristem Activity

Abstract Abstract Introduction Results Discussion Materials and Methods Authors' contributions Funding References The ubiquity and importance of short duplex RNAs, termed microRNA (miRNA), for normal development in higher eukaryotes are becoming increasingly clear. We had previously shown that reduction-of-function mutations in Arabidopsis thaliana DCL1 (DICER-LIKE1) gene, affecting the nucleus-localized protein that produces 19-25 nucleotides long miRNA species from longer double stranded RNA precursors, cause a delay in flowering by prolonging the period of juvenile organ development. Here we show that DCL1 transcription is increased at the critical phase of juvenile to reproductive developmental transition, and that DCL1 protein is localized in meri ...

Plant Biology↗

bioRxiv2014

Effect of alternating red and blue light irradiation generated by light emitting diodes on the growth of leaf lettuce

Because global climate change has made agricultural supply unstable, plant factories are expected to be a safe and stable means of food production. As the light source of a plant factory or controlled greenhouse, the light emitting diode (LED) is expected to solve cost problems and promote plant growth efficiently. In this study, we examined the light condition created by using monochromatic red and blue LEDs, to provide both simultaneous and alternating irradiation to leaf lettuce. The result was that simultaneous red and blue irradiation promoted plant growth more effectively than monochromatic and fluorescent light irradiation. Moreover, alternating red and blue light accelerated plant growth significantly even when the total light intensity per day was the same as with simultaneous irradiation. The fresh weight in altering irradiation was almost two times higher than with fluorescent light and about 1.6 times higher than with simultaneous irradiation. The growth-promoting effect of alternating irradiation of red and blue light was observed in different cultivars. From the results of experiments, we offer a novel plant growth method named \"Shigyo Method\", the core concept of which is the alternating irradiation of red and blue light.

Plant Biology↗

bioRxiv2014

A Genetic Screen Identifies Two Novel Rice Cysteine-rich Receptor-like Kinases That Are Required for the Rice NH1-mediated Immune Response

Over-expression of rice NH1 (NH1ox), the ortholog of Arabidopsis NPR1, confers immunity to bacterial and fungal pathogens and induces the appearance of necrotic lesions due to activation of defense genes at the pre-flowering stage. This lesion-mimic phenotype can be enhanced by the application of benzothiadiazole (BTH). To identify genes regulating these responses, we screened a fast neutron-irradiated NH1ox rice population. We identified one mutant, called sn11 (suppressor of NH1-mediated lesion-mimic 1), which is impaired both in BTH-induced necrotic lesion formation and in the immune response. Using a comparative genome hybridization approach employing rice whole genome tiling array, we identified 11 genes associated with the sn11 phenotype. Transgenic analysis revealed that RNA interference of two of the genes, encoding previously uncharacterized cysteine-rich receptor-like kinases (CRK6 and CRK10), re-created the sn11 phenotype. Elevated expression of CRK10 using an inducible expression system resulted in enhanced immunity. Quantitative PCR revealed that BTH treatment and elevated levels of rice NH1 and its paralog NH3 induced expression of CRK10 and CRK6 RNA. These results indicate that CRK6 and CRK10 are required for the BTH-activated immune response mediated by NH1.

Plant Biology↗

bioRxiv2014

Rice BiP3 regulates immunity mediated by the PRRs XA3 and XA21 but not immunity mediated by the NB-LRR protein, Pi5

Plant innate immunity is mediated by pattern recognition receptors (PRRs) and intracellular NB-LRR (nucleotide-binding domain and leucine-rich repeat) proteins. Overexpression of the endoplasmic reticulum (ER) chaperone, luminal-binding protein 3 (BiP3) compromises resistance to Xanthomonas oryzae pv. oryzae (Xoo) mediated by the rice PRR XA21 (Park et al., PLoS ONE 5(2): e9262). Here we show that BiP3 overexpression also compromises resistance mediated by rice XA3, a PRR that provides broad-spectrum resistance to Xoo. In contrast, BiP3 overexpression has no effect on resistance mediated by rice Pi5, an NB-LRR protein that confers resistance to the fungal pathogen Magnaporthe oryzae (M. oryzae). Our results suggest that rice BiP3 regulates membrane-resident PRR-mediated immunity.

Plant Biology↗

bioRxiv2014

Different profile of transcriptome between wheat Yunong 201 and its high-yield mutant Yunong 3114

Wheat is one of the most important crops in the world. With the exponentially increasing population and the need for ever increased food and feed production, an increased yield of wheat grain (as well as rice, maize and other grains) will be critical. Modern technologies are utilized to assist breeding programs. Such as the transcriptome sequencing, which greatly improves our genetic understanding, provides a platform for functional genomics research on crops. Herein, to get an overview of transcriptome characteristics of Yunong 3114, which is screened from the EMS mutagenized population of, a high quality Chinese winter noodle wheat, due to its different plant architecture as well as larger kernel size and higher grain weight, a high-throughput RNA sequencing based on next generation sequencing technology (Illumina) were performed. These unigenes were annotated by Blastx alignment against the NCBI non-redundant (nr), Clusters of orthologous groups (COG), gene orthology (GO), and the Kyoto Encyclopedia of Genesand Genomes (KEGG) databases. The 90.96% of the unigenes matched with protein in the NCBI nr database. Functional analysis identified that changes in several GO categories, including recognition of pollen, apoptotic process, defense response, receptor activity, protein kinase activity, DNA integration and so forth, played crucial roles in the high-yield characteristics of the mutant. Real-time PCR analysis revealed that the recognition of pollen related gene GsSRK is significantly up-regulated in Yunong 3114. In addition, alternative splicing (AS) analysis results indicated that mutation influence AS ratio, especially the retained introns, including the pollen related genes. Furthermore, the digital gene expression spectrum (DGE) profiling data provides comprehensive information at the transcriptional level that facilitates our understanding of the molecular mechanisms of various physiological aspects including development and high-yield of wheat. Together, these studies substantially increase our knowledge of potential genes and pathways for the genetic improvement of wheat and provide new insights into the yield and breeding strategies.

Plant Biology↗

bioRxiv2014

Transgenic expression of the dicotyledonous pattern recognition receptor EFR in rice leads to ligand-dependent activation of defense responses

Plant plasma membrane localized pattern recognition receptors (PRRs) detect extracellular pathogen-associated molecules. PRRs such as Arabidopsis EFR and rice XA21 are taxonomically restricted and are absent from most plant genomes. Here we show that rice plants expressing EFR or the chimeric receptor EFR::XA21, containing the EFR ectodomain and the XA21 intracellular domain, sense both Escherichia coli- and Xanthomonas oryzae pv. oryzae (Xoo)-derived elf18 peptides at sub-nanomolar concentrations. Treatment of EFR and EFR::XA21 rice leaf tissue with elf18 leads to MAP kinase activation, reactive oxygen production and defense gene expression. Although expression of EFR does not lead to robust enhanced resistance to fully virulent Xoo isolates, it does lead to quantitatively enhanced resistance to weakly virulent Xoo isolates. EFR interacts with OsSERK2 and the XA21 binding protein 24 (XB24), two key components of the rice XA21-mediated immune response. Rice-EFR plants silenced for OsSERK2, or overexpressing rice XB24 are compromised in elf18-induced reactive oxygen production and defense gene expression indicating that these proteins are also important for EFR-mediated signaling in transgenic rice. Taken together, our results demonstrate the potential feasibility of enhancing disease resistance in rice and possibly other monocotyledonous crop species by expression of dicotyledonous PRRs. Our results also suggest that Arabidopsis EFR utilizes at least a subset of the known endogenous rice XA21 signaling components.\n\nAuthor SummaryPlants possess multi-layered immune recognition systems. Early in the infection process, plants use receptor proteins to recognize pathogen molecules. Some of these receptors are present in only in a subset of plant species. Transfer of these taxonomically restricted immune receptors between plant species by genetic engineering is a promising approach for boosting the plant immune system. Here we show the successful transfer of an immune receptor from a species in the mustard family, called EFR, to rice. Rice plants expressing EFR are able to sense the bacterial ligand of EFR and elicit an immune response. We show that the EFR receptor is able to use components of the rice immune signaling pathway for its function. Under laboratory conditions, this leads to an enhanced resistance response to two weakly virulent isolates of an economically important bacterial disease of rice.

Plant Biology↗

bioRxiv2014

Growth of Primary and Lateral Roots of Vicia faba L. in the Solution of Calcium Sulfate

The presence of calcium sulfate in cultivating solution prevents bacterial contamination, browning/lignification and the death of the roots. There is no need for surface sterilization of seeds. No other ingredients, beside calcium sulfate, are needed for the healthy growth of the primary and lateral roots. There is no need to change the solution for several weeks when up to 60 lateral roots per seed can appear.\n\nA modification of the two-stage growing technique where the seeds are first suspended in moist air over the cultivating solution to grow primary roots, and then, the primary roots are covered with the cultivating solution to grow lateral roots, was used.\n\nThe hypothesis is put forward that primary roots actually need water as a liquid to expel air, as the air is probably preventing the appearance of lateral roots.

Plant Biology↗

bioRxiv2014

Using more than the oldest fossils: Dating Osmundaceae by three Bayesian clock approaches

A major concern in molecular clock dating is how to use information from the fossil record to calibrate genetic distances from DNA sequences. Here we apply three Bayesian dating methods that differ in how calibration is achieved-- node dating(ND) in BEAST, total evidence(TE) dating in MrBayes, and the fossilised birth-death(FBD) in FDPPDiv--to infer divergence times in the Osmundaceae or royal ferns. Osmundaceae have 13 species in four genera, two mainly in the Northern Hemisphere and two in South Africa and Australasia; they are the sister clade to the remaining leptosporangiate ferns. Their fossil record consists of at least 150 species in [~]17 genera and three extinct families. For ND, we used the five oldest fossils, while for TE and FBD dating, which do not require forcing fossils to nodes and thus can use more fossils, we included up to 36 rhizome and frond compression/impression fossils, which for TE dating were scored for 33 morphological characters. We also subsampled 10%, 25%, and 50% of the 36 fossils to assess model sensitivity. FBD-derived divergence dates were generally greater than ages inferred from ND dating; two of seven TE-derived ages agreed with FBD-obtained ages, the others were much younger or much older than ND or FBD ages. We favour the FBD-derived ages because they best match the Osmundales fossil record (including Triassic fossils not used in our study). Under the preferred model, the clade encompassing extant Osmundaceae (and many fossils) dates to the latest Palaeozoic to Early Triassic; divergences of the extant species occurred during the Neogene. Under the assumption of constant speciation and extinction rates, FBD yielded 0.0299 (0.0099-0.0549) and 0.0240 (0.0039-0.0495) for these rates, whereas neontological data yielded 0.0314 and 0.0339. However, FBD estimates of speciation and extinction are sensitive to violations in the assumption of continuous fossil sampling, therefore these estimates should be treated with caution.#

Plant Biology↗

bioRxiv2014

Distinct regulatory modules identified in the promoters of wheat Glu-1 genes suggest different regulatory mechanisms

High molecular weight glutenin subunits of wheat are economically important seed storage proteins. They are coded by paralog pairs of the Glu-1 gene on each of the three genomes in the hexaploid wheat. Their expressions are under both temporal and spatial control. Many factors have been identified that influence the activity of Glu-1 genes, but the underlying regulatory mechanisms are still unclear. In order to identify motifs and motif clusters responsible for quantitative regulation of Glu-1 gene expressions, promoter profiles and transcription dynamics of the genes were analysed. It was found that promoter motif compositions of homoeolog Glu-1 genes are conserved. Our results demonstrated that while promoter profiles explain the differences of expression between homoeologs and between paralogs, it does not explain the variation of activity between alleles. Interestingly, our analyses revealed that the promoters of Glu-1 genes are divided into six cis-regulatory modules that are either locally overrepresented by binding sites belonging to unique but distinct transcription factor (TF) families or have conserved motif clusters. Moreover, our analyses demonstrated that the varying expression dynamics of TFs across genotypes is likely to be the primary contributor of the allelic variation of Glu-1 gene expressions. Thus, the six putative cis-regulatory modules in the Glu-1 gene promoters bound by the differentially expressed TFs are suggested to play a key role in the quantitative and tissue specific regulation of these genes.

Plant Biology↗

bioRxiv2014

A systematic simulation of the effect of salicylic acid on sphingolipid metabolism

AbstractThe phytohormone salicylic acid (SA) affects plant development and defense responses. Recent studies revealed that SA is also involved in the regulation of sphingolipid metabolism, but the details of this regulation remain to be explored. Here, we use in silico Flux Balance Analysis (FBA) with published microarray data to construct a whole-cell simulation model, including 23 pathways, 259 reactions and 172 metabolites, to predict the alterations in flux of major sphingolipid species after treatment with exogenous SA. This model predicts significant changes in fluxes of certain sphingolipid species after SA treatment, changes that likely trigger downstream physiological and phenotypic effects. To validate the simulation, we used isotopic non-stationary metabolic flux analysis to measure sphingolipid contents and turnover rate in Arabidopsis thaliana seedlings treated with SA or the SA analog benzothiadiazole (BTH). The results show that both SA and BTH affect sphingolipid metabolism by not only concentration of certain species, but also the optimal flux distribution and turnover rate of sphingolipid contents. Our strategy allows us to formally estimate sphingolipid fluxes on a short time scale and gives us a systemic view of the effect of SA on sphingolipid homeostasis.

Plant Biology↗

bioRxiv2014

Phytophthora infestans RXLR-WY effector AVR3a associates with a Dynamin-Related Protein involved in endocytosis of a plant pattern recognition receptor

Perception of pathogen associated molecular patterns (PAMPs) by cell surface localized pattern recognition receptors (PPRs), activates plant basal defense responses in a process known as PAMP/PRR-triggered immunity (PTI). In turn, pathogens deploy effector proteins that interfere with different steps in PTI signaling. However, our knowledge of PTI suppression by filamentous plant pathogens, i.e. fungi and oomycetes, remains fragmentary. Previous work revealed that BAK1/SERK3, a regulatory receptor of several PRRs, contributes to basal immunity against the Irish potato famine pathogen Phytophthora infestans. Moreover BAK1/SERK3 is required for the cell death induced by P. infestans elicitin INF1, a protein with characteristics of PAMPs. The P. infestans host-translocated RXLR-WY effector AVR3a is known to supress INF1-mediated defense by binding the E3 ligase CMPG1. In contrast, AVR3aKl-Y147del, a deletion mutant of the C-terminal tyrosine of AVR3a, fails to bind CMPG1 and suppress INF1 cell death. Here we studied the extent to which AVR3a and its variants perturb additional BAK1/SERK3 dependent PTI responses using the plant PRR FLAGELLIN SENSING 2 (FLS2). We found that all tested variants of AVR3a, including AVR3aKl-Y147del, suppress early defense responses triggered by the bacterial flagellin-derived peptide flg22 and reduce internalization of activated FLS2 from the plasma membrane without disturbing its nonactivated localization. Consistent with this effect of AVR3a on FLS2 endocytosis, we discovered that AVR3a associates with the Dynamin-Related Protein DRP2, a plant GTPase implicated in receptor-mediated endocytosis. Interestingly, DRP2 is required for ligand-induced FLS2 internalization but does not affect internalization of the growth receptor BRASSINOSTEROID INSENSITIVE 1 (BRI1). Furthermore, overexpression of DRP2 suppressed accumulation of reactive oxygen species triggered by PAMP treatment. We conclude that AVR3a associates with a key cellular trafficking and membrane-remodeling complex involved in immune receptor-mediated endocytosis and signaling. AVR3a is a multifunctional effector that can suppress BAK1/SERK3 mediated immunity through at least two different pathways.\n\nAUTHOR SUMMARYPlants have a basal layer of immunity to mount defense responses against invading pathogens; in turn, pathogens deploy effector proteins to subvert plant immunity and manipulate host processes to enable parasitic infection. The Irish potato famine pathogen Phytophthora infestans has a large set of effectors that target multiple host cellular sites. The best-characterized P. infestans effector AVR3a supports enhanced infection and suppresses the cell death induced by the P. infestans protein INF1-elicitin. Previous work demonstrated that the plant immunity co-receptor BAK1/SERK3 contributes to basal immunity to P. infestans and that the RXLR-WY effector of P. infestans suppresses BAK1/SERK3-mediated immunity by binding the E3 ligase protein CMPG1. Here we show that AVR3a suppresses additional defense responses mediated by BAK1/SERK3 independently of CMPG1. AVR3a reduces the endocytosis of the plant receptor FLS2, which recognizes the flagellin-derived peptide flg22 in a BAK1/SERK3 dependent manner. Furthermore, we demonstrate that AVR3a associates with the Dynamin-Related Protein DRP2, a plant GTPase involved in receptor-mediated endocytosis that is required for FLS2 internalization. Our work revealed that AVR3a is a multifunctional effector that perturbs cellular trafficking initiated at the cell periphery by at least two mechanisms, and that this effector associates with a key cellular trafficking and membrane-remodeling complex involved in immune receptor-mediated endocytosis and signaling.

Plant Biology↗

bioRxiv2015

Identification of an Arabidopsis Aminotransferase that Facilitates Tryptophan and Auxin Homeostasis

IAA plays a critical role in regulating numerous aspects of plant growth and development. While there is much genetic support for tryptophan-dependent (Trp-D) IAA synthesis pathways, there is little genetic evidence for tryptophan-independent (Trp-I) IAA synthesis pathways. Using Arabidopsis, we identified two mutant alleles of ISS1 (Indole Severe Sensitive) that display indole-dependent IAA overproduction phenotypes including leaf epinasty and adventitious rooting. Stable isotope labeling showed that iss1, but not WT, uses primarily Trp-I IAA synthesis when grown on indolesupplemented medium. In contrast, both iss1 and WT use primarily Trp-D IAA synthesis when grown on unsupplemented medium. iss1 seedlings produce 8-fold higher levels of IAA when grown on indole and surprisingly have a 174-fold increase in Trp. These findings indicate that the iss1 mutants increase in Trp-I IAA synthesis is due to a loss of Trp catabolism. ISS1 was identified as At1g80360, a predicted aromatic aminotransferase, and in vitro and in vivo analysis confirmed this activity. At1g80360 was previously shown to primarily carry out the conversion of indole-3-pyruvic acid to Trp as an IAA homeostatic mechanism in young seedlings. Our results suggest that in addition to this activity, in more mature plants ISS1 has a role in Trp catabolism and possibly in the metabolism of other aromatic amino acids. We postulate that this loss of Trp catabolism impacts the use of Trp-D and/or Trp-I IAA synthesis pathways.

Plant Biology↗

bioRxiv2015

In plants, decapping prevents RDR6-dependent production of small interfering RNAs from endogenous mRNAs

Cytoplasmic degradation of endogenous RNAs is an integral part of RNA quality control (RQC) and often relies on the removal of the 5' cap structure and their subsequent 5 to 3 degradation in cytoplasmic processing (P-)bodies. In parallel, many eukaryotes degrade exogenous and selected endogenous RNAs through post-transcriptional gene silencing (PTGS). In plants, PTGS depends on small interfering (si)RNAs produced after the conversion of single-stranded RNAs to double-stranded RNAs by the cellular RNA DEPENDENT RNA POLYMERASE 6 (RDR6) in cytoplasmic siRNA-bodies. PTGS and RQC compete for transgene-derived RNAs, but it is unknown whether this competition also occurs for endogenous transcripts. We show that the lethality of decapping mutants is suppressed by impairing RDR6 activity. We establish that upon decapping impairment hundreds of endogenous mRNAs give rise to a new class of rqc-siRNAs, that over-accumulate when RQC processes are impaired, a subset of which depending on RDR6 for their production. We observe that P- and siRNA-bodies often are dynamically juxtaposed, potentially allowing for crosstalk of the two machineries. Our results suggest that the decapping of endogenous RNA limits their entry into the PTGS pathway. We anticipate that the rqc-siRNAs identified in decapping mutants represent a subset of a larger ensemble of endogenous siRNAs.

Plant Biology↗

bioRxiv2015

Natural Variants of ELF3 Affect Thermomorphogenesis by Transcriptionally Modulating PIF4-Dependent Auxin Response Genes

Perception and transduction of temperature changes result in altered growth enabling plants to adapt to increased ambient temperature. While PHYTOCHROME-INTERACTING FACTOR4 (PIF4) has been identified as a major ambient temperature signaling hub, its upstream regulation seems complex and is poorly understood. Here, we exploited natural variation for thermo-responsive growth in Arabidopsis thaliana using quantitative trait locus (QTL) analysis. We identified GIRAFFE2.1, a major QTL explaining ~18% of the phenotypic variation for temperature-induced hypocotyl elongation in the Bay-0 x Sha recombinant inbred line population. Transgenic complementation demonstrated that allelic variation in the circadian clock regulator EARLY FLOWERING3 (ELF3) is underlying this QTL. The source of variation could be allocated to a single nucleotide polymorphism in the ELF3 coding region, resulting in differential expression of PIF4 and its target genes, likely causing the observed natural variation in thermo-responsive growth. In combination with other recent studies, this work establishes the role of ELF3 in the ambient temperature signaling network. Natural variation of ELF3-mediated gating of PIF4 expression during nightly growing periods seems to be affected by a coding sequence quantitative trait nucleotide that confers a selective advantage in certain environments. In addition, natural ELF3 alleles seem to differentially integrate temperature and photoperiod cues to induce architectural changes. Thus, ELF3 emerges as an essential coordinator of growth and development in response to diverse environmental cues and implicates ELF3 as an important target of adaptation.

Plant Biology↗

bioRxiv2015

The NLR helper protein NRC3 but not NRC1 is required for Pto-mediated cell death in Nicotiana benthamiana

Intracellular immune receptors of the nucleotide-binding leucine-rich repeat (NB-LRR or NLR) proteins often function in pairs, with \"helper\" proteins required for the activity of \"sensors\" that mediate pathogen recognition. The NLR helper NRC1 (NB-LRR protein required for HR-associated cell death 1) has been described as a signalling hub required for the cell death mediated by both cell surface and intracellular immune receptors in the model plant Nicotiana benthamiana. However, this work predates the availability of the N. benthamiana genome and whether NRC1 is indeed required for the reported phenotypes has not been confirmed. Here, we investigated the NRC family of solanaceous plants using a combination of genome annotation, phylogenetics, gene silencing and genetic complementation experiments. We discovered that a paralog of NRC1, we termed NRC3, is required for the hypersensitive cell death triggered by the disease resistance protein Pto but not Rx and Mi-1.2. NRC3 may also contribute to the hypersensitive cell death triggered by the receptor-like protein Cf-4. Our results highlight the importance of applying genetic complementation to validate gene function in RNA silencing experiments.

Plant Biology↗