Latest Accepted Articles

  Special Issue: Cell Signaling
Unraveling salt stress signaling in plants
Author: Yongqing Yang, Yan Guo
Received: January 30, 2018         Accepted: June 8, 2018
Online Date: June 15, 2018
DOI: 10.1111/jipb.12689
                     
      
    

Salt stress is a major environmental factor limiting plant growth and productivity. A better understanding of the mechanisms mediating salt resistance will help researchers design ways to improve crop performance under adverse environmental conditions. Salt stress can lead to ionic stress, osmotic stress, and secondary stresses, particularly oxidative stress, in plants. Therefore, to adapt to salt stress, plants rely on signals and pathways that re©\establish cellular ionic, osmotic, and reactive oxygen species (ROS) homeostasis. Over the past two decades, genetic and biochemical analyses have revealed several core stress signaling pathways that participate in salt resistance. The Salt Overly Sensitive (SOS) signaling pathway plays a key role in maintaining ionic homeostasis, via extruding sodium ions into the apoplast. Mitogen©\activated protein kinase (MAPK) cascades mediate ionic, osmotic, and ROS homeostasis. SnRK2 (sucrose nonfermenting 1©\related protein kinase 2) proteins are involved in maintaining osmotic homeostasis. In this review, we discuss recent progress in identifying the components and pathways involved in the plant's response to salt stress and their regulatory mechanisms. We also review progress in identifying sensors involved in salt©\induced stress signaling in plants.

Abstract (Browse 17)   |   Full Text
The crossroads of receptor©\mediated signaling and endocytosis in plants
Author: Lucas Alves Neubus Claus, Daniel V. Savatin and Eugenia Russinova
Received: February 27, 2018         Accepted: June 5, 2018
Online Date: June 7, 2018
DOI: 10.1111/jipb.12672
                     
      
    

Plants deploy numerous plasma membrane receptors to sense and rapidly react to environmental changes. Correct localization and adequate protein levels of the cell©\surface receptors are critical for signaling activation and modulation of plant development and defense against pathogens. After ligand binding, receptors are internalized for degradation and signaling attenuation. However, one emerging notion is that the ligand©\induced endocytosis of receptor complexes is important for the signaling duration, amplitude, and specificity. Recently, mutants of major endocytosis players, including clathrin and dynamin, have been shown to display defects in activation of a subset of signal transduction pathways, implying that signaling in plants might not be restricted to the plasma membrane only. Here, we summarize the up©\to©\date knowledge of receptor complex endocytosis and its effect on the signaling outcome in the context of plant development and immunity.

Abstract (Browse 17)   |   Full Text
Ethylene©\induced microtubule reorientation is essential for fast inhibition of root elongation in Arabidopsis
Author: Yichuan Wang, Yusi Ji, Ying Fu and Hongwei Guo
Received: February 8, 2018         Accepted: May 9, 2018
Online Date: May 12, 2018
DOI: 10.1111/jipb.12666
                     
      
    

Microtubule reorientation is a long©\standing observation that has been implicated in regulating the inhibitory effect of ethylene on axial elongation of plant cells. However, the signaling mechanism underlying ethylene©\induced microtubule reorientation has remained elusive. Here, we reveal, by live confocal imaging and kinetic root elongation assays, that the time courses of ethylene©\induced microtubule reorientation and root elongation inhibition are highly correlated, and that microtubule reorientation is required for the full responsiveness of root elongation to ethylene treatment. Our genetic analysis demonstrated that the effect of ethylene on microtubule orientation and root elongation is mainly transduced through the canonical linear ethylene signaling pathway. By employing pharmacological and genetic analyses, we demonstrate further that the TIR1/AFBs©\Aux/IAAs©\ARFs auxin signaling pathway, but not the ABP1©\ROP6©\RIC1 auxin signaling branch, is essential for ethylene©\induced microtubule reorientation and root elongation inhibition. Together, these findings offer evidence for the functional significance and elucidate the signaling mechanism for ethylene©\induced microtubule reorientation in fast root elongation inhibition in Arabidopsis.

Abstract (Browse 41)   |   Full Text
Receptor©\like protein kinases: Key regulators controlling root hair development in Arabidopsis thaliana
Author: Zhuoyun Wei and Jia Li
Received: March 14, 2018         Accepted: April 27, 2018
Online Date: May 4, 2018
DOI: 10.1111/jipb.12663
                     
      
    

Root hairs are tubular outgrowths specifically differentiated from epidermal cells in differentiation zone. The formation of root hairs greatly increases the surface area of a root and maximizes its ability to absorb water and inorganic nutrients essential for plant growth and development. Root hair development is strictly regulated by intracellular and intercellular signal communications. Cell surface©\localized receptor©\like protein kinases (RLKs) have been discovered as important components in these cellular processes. In this review, the functions of a number of key RLKs in regulating Arabidopsis root hair development are discussed, especially those involved in root epidermal cell fate determination and root hair tip growth.

Abstract (Browse 35)   |   Full Text
Insights into the regulation of CBF cold signaling in plants
Author: Jingyan Liu, Yiting Shi, and Shuhua Yang
Received: February 18, 2018         Accepted: April 16, 2018
Online Date: April 18, 2018
DOI: 10.1111/jipb.12657
                     
      
    

Cold temperatures, a major abiotic stress, threaten the growth and development of plants worldwide. To cope with this adverse environmental cue, plants from temperate climates have evolved an array of sophisticated mechanisms to acclimate to cold periods, increasing their ability to tolerate freezing stress. Over the last decade, significant progress has been made in determining the molecular mechanisms underpinning cold acclimation following the identification of several pivotal components, including candidates for cold sensors, protein kinases, and transcription factors. With these developments, we have a better understanding of the CBF©\dependent cold©\signaling pathway. In this review, we summarize recent progress made in elucidating the cold©\signaling pathways, especially the CBF©\dependent pathway, and describe the regulatory function of the crucial components of the plant cold signaling. We also discuss the unsolved questions that should be the focus of future work.

Abstract (Browse 44)   |   Full Text
Phosphatidic acid (PA) plays key roles regulating plant development and stress responses
Author: Hong-Yan Yao and Hong-Wei Xue
Received: February 27, 2018         Accepted: April 11, 2018
Online Date: April 16, 2018
DOI: 10.1111/jipb.12655
                     
      
    

Phospholipids, including phosphatidic acid (PA), phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), phosphatidylserine (PS) and phosphoinositides, have emerged as an important class of cellular messenger molecules in various cellular and physiological processes, of which PA attracts much attentions of the researchers. In addition to its effect on stimulating the vesicle trafficking, many studies have demonstrated that PA plays a crucial role in various signaling pathways by binding target proteins and regulating their activity and subcellular localization. Here, we summarize the functional mechanisms and target proteins underlying PA©\mediated regulation of cellular signaling, development, hormonal responses, and stress responses in plants.

Abstract (Browse 63)   |   Full Text
ROS signaling and stomatal movement in plant responses to drought stress and pathogen attack
Author: Junsheng Qi, Chun-Peng Song, Baoshan Wang, Jianmin Zhou, Jaakko Kangasjärvi, Jian-Kang Zhu and Zhizhong Gong
Received: February 20, 2018         Accepted: April 8, 2018
Online Date: April 16, 2018
DOI: 10.1111/jipb.12654
                     
      
    

Stomata, the pores formed by a pair of guard cells, are the main gateways for water transpiration and photosynthetic CO2 exchange, as well as pathogen invasion in land plants. Guard cell movement is regulated by a combination of environmental factors including water status, light, CO2 levels and pathogen attack, as well as endogenous signals such as abscisic acid and apoplastic reactive oxygen species (ROS). Under abiotic and biotic stress conditions, extracellular ROS are mainly produced by plasma membrane©\localized NADPH oxidases, whereas intracellular ROS are produced in multiple organelles. These ROS form a sophisticated cellular signaling network, with the accumulation of apoplastic ROS an early hallmark of stomatal movement. Here, we review recent progress in understanding the molecular mechanisms of the ROS signaling network, primarily during drought stress and pathogen attack. We summarize the roles of apoplastic ROS in regulating stomatal movement, ABA and CO2 signaling, and immunity responses. Finally, we discuss ROS accumulation and communication between organelles and cells. This information provides a conceptual framework for understanding how ROS signaling is integrated with various signaling pathways during plant responses to abiotic and biotic stress stimuli.

Abstract (Browse 61)   |   Full Text
  Special Issue on Plant Synthetic Biology
On the role of the tricarboxylic acid cycle in plant productivity
Author: Youjun Zhang and Alisdair R. Fernie
Received: June 4, 2018         Accepted: June 18, 2018
Online Date: June 19, 2018
DOI: 10.1111/jipb.12690
                     
      
    

The tricarboxylic acid (TCA) cycle is one of the canonical energy pathways of living systems, as well as being an example of a pathway in which dynamic enzyme assemblies, or metabolons, are well characterized. The role of the enzymes have been the subject of saturated transgenesis approaches, whereby the expression of the constituent enzymes were reduced or knocked out in order to ascertain their in vivo function. Some of the resultant plants exhibited improved photosynthesis and plant growth, under controlled greenhouse conditions. In addition,overexpression of the endogenous genes, or heterologous forms of a number of the enzymes, has been carried out in tomato fruit and the roots of a range of species, and in some instances improvement in fruit yield and postharvest properties and plant performance, under nutrient limitation have been reported, respectively. Given a number of variants, in nature, we discuss possible synthetic approaches involving introducing these variants, or at least a subset of them, into plants. We additionally discuss the likely consequences of introducing synthetic metabolons, wherein certain pairs of reactions are artificially permanently assembled, into plants, and speculate as to future strategies to further improve plant productivity by manipulation of the core metabolic pathway.

Abstract (Browse 7)   |   Full Text
  Invited Expert Review
Expanding roles for pectins in plant development
Author: Adam M. Saffer
Received: March 23, 2018         Accepted: May 2, 2018
Online Date: May 4, 2018
DOI: 10.1111/jipb.12662
                     
      
    

Pectins are complex cell wall polysaccharides important for many aspects of plant development. Recent studies have discovered extensive physical interactions between pectins and other cell wall components, implicating pectins in new molecular functions. Pectins are often localized in spatially restricted patterns, and some of these non©\uniform pectin distributions contribute to multiple aspects of plant development, including the morphogenesis of cells and organs. Furthermore, a growing number of mutants affecting cell wall composition have begun to reveal the distinct contributions of different pectins to plant development. This review discusses the interactions of pectins with other cell wall components, the functions of pectins in controlling cellular morphology, and how non©\uniform pectin composition can be an important determinant of developmental processes.

Abstract (Browse 40)   |   Full Text
  Molecular Physiology
Identification of novel cis©\elements bound by BplMYB46 involved in abiotic stress responses and secondary wall deposition
Author: Huiyan Guo, Liuqiang Wang, Chuanping Yang, Yiming Zhang, Chunrui Zhang, Chao Wang
Received: February 19, 2018         Accepted: June 1, 2018
Online Date: June 7, 2018
DOI: 10.1111/jipb.12671
                     
      
    

Transcription factors (TFs) play vital roles in various biological processes by binding to cis©\acting elements to control expressions of their target genes. The MYB TF BplMYB46, from Betula platyphylla, is involved in abiotic stress responses and secondary wall deposition. In the present study, we used a TF©\centered yeast one©\hybrid technology (TF©\centered Y1H) to identify the cis©\acting elements bound by BplMYB46. We screened a short©\insert random library and identified three cis©\elements bound by BplMYB46: an E©\box (CA(A/T/C)(A/G/C)TG) and two novel motifs, a TC©\box (T(G/A)TCG(C/G)) and a GT©\box (A(G/T)T(A/C)GT(T/G)C). Chromatin immunoprecipitation (ChIP) and effector©\reporter coexpression assays in Nicotiana tabacum confirmed binding of BplMYB46 to the TC©\box, GT©\box, and E©\box motifs in the promoters of the phenylalanine ammonia lyase (PAL), peroxidase (POD), and superoxide dismutase (SOD) genes, which function in abiotic stress tolerance and secondary wall biosynthesis. This finding improves our understanding of potential regulatory mechanisms in the response to abiotic stress and secondary wall deposition of BplMYB46 in B. platyphylla.

Abstract (Browse 23)   |   Full Text
Arabidopsis VQ10 interacts with WRKY8 to modulate basal defense against Botrytis cinerea
Author: Junqiu Chen, Houping Wang, Yang Li, Jinjing Pan, Yanru Hu and Diqiu Yu
Received: March 15, 2018         Accepted: May 3, 2018
Online Date: May 4, 2018
DOI: 10.1111/jipb.12664
                     
      
    

Recent studies in Arabidopsis have revealed that some VQ motif©\containing proteins physically interact with WRKY transcription factors; however, their specific biological functions are still poorly understood. In this study, we confirmed the interaction between VQ10 and WRKY8, and found that VQ10 and WRKY8 formed a complex in the plant cell nucleus. Yeast two©\hybrid analysis showed that the middle region of WRKY8 and the VQ motif of VQ10 are critical for their interaction, and that their interaction promotes the DNA©\binding activity of WRKY8. Further investigation revealed that the VQ10 protein was exclusively localized in the nucleus, and VQ10 was predominantly expressed in siliques. VQ10 expression was strongly responsive to the necrotrophic fungal pathogen Botrytis cinerea and defense©\related hormones. Phenotypic analysis showed that disruption of VQ10 increased mutant plants susceptibility to the fungal pathogen B. cinerea, whereas constitutively©\expressing of VQ10 enhanced transgenic plants resistance to B. cinerea. Consistent with this, expression of the defense©\related PLANT DEFENSIN1.2 (PDF1.2) gene was decreased in vq10 mutant plants after B. cinerea infection but increased in VQ10©\overexpressing transgenic plants. Taken together, our findings provide evidence that VQ10 physically interacts with WRKY8 and positively regulates plant basal resistance against the necrotrophic fungal pathogen B. cinerea.

Abstract (Browse 45)   |   Full Text
  Functional Omics and Systems Biology
A genome©\wide association study of early©\maturation traits in upland cotton based on the CottonSNP80K array
Author: Chengqi Li, Yuanyuan Wang, Nijiang Ai, Yue Li and Jiafeng Song
Received: February 2, 2018         Accepted: May 31, 2018
Online Date: June 7, 2018
DOI: 10.1111/jipb.12673
                     
      
    

Genome©\wide association studies (GWAS) efficiently identify genetic loci controlling traits at a relatively high resolution. In this study, variations in major early©\maturation traits, including seedling period (SP), bud period (BP), flower and boll period (FBP), and growth period (GP), of 169 upland cotton accessions were investigated, and a GWAS of early maturation was performed based on a CottonSNP80K array. A total of 49,650 high©\quality single©\nucleotide polymorphisms (SNPs) were screened, and 29 significant SNPs located on chromosomes A6, A7, A8, D1, D2, and D9, were repeatedly identified as associated with early©\maturation traits, in at least two environments or two algorithms. Of these 29 significant SNPs, 1, 12, 11, and 5 were related to SP, BP, FBP, and GP, respectively. Six peak SNPs, TM47967, TM13732, TM20937, TM28428, TM50283, and TM72552, exhibited phenotypic contributions of ∼10%, which could allow them to be used for marker©\assisted selection. One of these, TM72552, as well as four other SNPs, TM72554, TM72555, TM72558, and TM72559, corresponded to the quantitative trait loci previously reported. In total, 274 candidate genes were identified from the genome sequences of upland cotton and were categorized based on their functional annotations. Finally, our studies identified Gh_D01G0340 and Gh_D01G0341 as potential candidate genes for improving cotton early maturity.

Abstract (Browse 18)   |   Full Text
Characterization of maize leaf Pyruvate Orthophosphate Dikinase using high throughput sequencing
Author: Yuling Zhang, Rita Giuliani, Youjun Zhang, Yang Zhang, Wagner Luiz Araujo, Baichen Wang, Peng Liu, Qi Sun, Asaph Cousins, Gerald Edwards, Alisdair Fernie, and Thomas P. Brutnell, Pinghua Li
Received: March 18, 2018         Accepted: April 12, 2018
Online Date: April 17, 2018
DOI: 10.1111/jipb.12656
                     
      
    

In C4 photosynthesis, pyruvate orthophosphate dikinase (PPDK) catalyzes the regeneration of phosphoenolpyruvate in the carbon shuttle pathway. Although the biochemical function of PPDK in maize is well characterized, a genetic analysis of PPDK has not been reported. In this study, we utilize the maize transposable elements Mutator and Ds to generate multiple mutant alleles of PPDK. Loss©\of©\function mutants are seedling lethal even when plants were grown under 2% CO2, and they show very low capacity for CO2 assimilation indicating C4 photosynthesis is essential in maize. Using RNA©\seq and GC©\MS technologies, we examined the transcriptional and metabolic responses to a deficiency in PPDK activity. These results indicate loss of PPDK results in down©\regulation of gene expression of enzymes of the C4 cycle, the Calvin cycle, and components of photochemistry. Furthermore, the loss of PPDK did not change Kranz anatomy, indicating that this metabolic defect in the C4 cycle did not impinge on the morphological differentiation of C4 characters. However, sugar metabolism and nitrogen utilization were altered in the mutants. An interaction between light intensity and genotype was also detected from transcriptome profiling, suggesting altered transcriptional and metabolic responses to environmental and endogenous signals in the PPDK mutants.

Abstract (Browse 59)   |   Full Text
  Plant-abiotic Interactions
Arabidopsis SUMO protease ASP1 positively regulates ABA signaling during early seedling development  
Author: Qiongli Wang, Gao-Ping Qu, Xiangxiong Kong, Yan Yan, Jigang Li and Jing Bo Jin
Received: April 8, 2018         Accepted: May 10, 2018
Online Date: May 22, 2018
DOI: 10.1111/jipb.12669
                     
      
    

The small ubiquitin©\related modifier (SUMO) modification plays an important role in the regulation of abscisic acid (ABA) signaling, but the function of the SUMO protease, in ABA signaling, remains largely unknown. Here, we show that the SUMO protease, ASP1 positively regulates ABA signaling. Mutations in ASP1 resulted in an ABA©\insensitive phenotype, during early seedling development. Wild©\type ASP1 successfully rescued, whereas an ASP1 mutant (C577S), defective in SUMO protease activity, failed to rescue, the ABA©\insensitive phenotype of asp1©\1. Expression of ABI5 and MYB30 target genes was attenuated in asp1©\1 and our genetic analyses revealed that ASP1 may function upstream of ABI5 and MYB30. Interestingly, ASP1 accumulated upon ABA treatment, and ABA©\induced accumulation of ABI5 (a positive regulator of ABA signaling) was abolished, whereas ABA©\induced accumulation of MYB30 (a negative regulator of ABA signaling) was increased in asp1©\1. These findings support the hypothesis that increased levels of ASP1, upon ABA treatment, tilt the balance between ABI5 and MYB30 towards ABI5©\mediated ABA signaling.

Abstract (Browse 33)   |   Full Text
bHLH104 confers tolerance to cadmium stress in Arabidopsis thaliana
Author: Xiani Yao, Yuerong Cai, Diqiu Yu, Gang Liang
Received: February 10, 2018         Accepted: April 16, 2018
Online Date: April 18, 2018
DOI: 10.1111/jipb.12658
                     
      
    

Cd is a non©\essential heavy metal that is toxic to both plants and animals. Here, we reveal that the transcription factor bHLH104 positively regulates Cd tolerance in Arabidopsis thaliana. We found that Fe deficiency©\responsive genes were induced by Cd treatment, and that their upregulation was suppressed in bhlh104 loss©\of©\function mutants but enhanced upon overexpression of bHLH104. Correspondingly, the bhlh104 mutants displayed sensitivity to Cd stress, whereas plants overexpressing bHLH104 exhibited enhanced Cd tolerance. Further analysis suggested that bHLH104 positively regulates four heavy metal detoxification©\associated genes, IREG2, MTP3, HMA3 and NAS4, which play roles in Cd sequestration and tolerance. The bHLH104 overexpression plants accumulated high levels of Cd in the root but low levels of Cd in the shoot, which might contribute to the Cd tolerance in those lines. The present study thus points to bHLH104 as a potentially useful tool for genetic engineering of plants with enhanced Cd tolerance.

Abstract (Browse 45)   |   Full Text
  Cell and Developmental Biology
Proteome analysis of peroxisomes from dark©\treated senescent Arabidopsis leaves
Author: Ronghui Pan, Sigrun Reumann, Piotr Lisik, Stefanie Tietz, Laura J. Olsen and Jianping Hu
Received: May 8, 2018         Accepted: May 29, 2018
Online Date: June 7, 2018
DOI: 10.1111/jipb.12670
                     
      
    

Peroxisomes compartmentalize a dynamic suite of biochemical reactions and play a central role in plant metabolism, such as the degradation of hydrogen peroxide, metabolism of fatty acids, photorespiration, and the biosynthesis of plant hormones. Plant peroxisomes have been traditionally classified into three major subtypes, and in©\depth mass spectrometry (MS)©\based proteomics has been performed to explore the proteome of the two major subtypes present in green leaves and etiolated seedlings. Here, we carried out a comprehensive proteome analysis of peroxisomes from Arabidopsis leaves given a 48©\h dark treatment. Our goal was to determine the proteome of the third major subtype of plant peroxisomes from senescent leaves, and further catalog the plant peroxisomal proteome. We identified a total of 111 peroxisomal proteins and verified the peroxisomal localization for six new proteins with potential roles in fatty acid metabolism and stress response by in vivo targeting analysis. Metabolic pathways compartmentalized in the three major subtypes of peroxisomes were also compared, which revealed a higher number of proteins involved in the detoxification of reactive oxygen species in peroxisomes from senescent leaves. Our study takes an important step towards mapping the full function of plant peroxisomes.

Abstract (Browse 16)   |   Full Text
Non©\dormant Axillary Bud 1 regulates axillary bud outgrowth in sorghum
Author: Jun Chen, Limin Zhang, Mengjiao Zhu, Lijie Han, Ya Lv, Yishan Liu, Pan Li, Haichun Jing and Hongwei Cai
Received: April 3, 2018         Accepted: May 4, 2018
Online Date: May 8, 2018
DOI: 10.1111/jipb.12665
                     
      
    

Tillering contributes to grain yield and plant architecture and therefore is an agronomically important trait in sorghum (Sorghum bicolor). Here, we identified and functionally characterized a mutant of the Non©\dormant Axillary Bud 1 (NAB1) gene from an ethyl methanesulfonate©\mutagenized sorghum population. The nab1 mutants have increased tillering and reduced plant height. Map©\based cloning revealed that NAB1 encodes a carotenoid©\cleavage dioxygenase 7 (CCD7) orthologous to rice (Oryza sativa) HIGH©\TILLERING DWARF1/DWARF17 and Arabidopsis thaliana MORE AXILLARY BRANCHING 3. NAB1 is primarily expressed in axillary nodes and tiller bases and NAB1 localizes to chloroplasts. The nab1 mutation causes outgrowth of basal axillary buds; removing these non©\dormant basal axillary buds restored the wild©\type phenotype. The tillering of nab1 plants was completely suppressed by exogenous application of the synthetic strigolactone analog GR24. Moreover, the nab1 plants had no detectable strigolactones and displayed stronger polar auxin transport than wild©\type plants. Finally, RNA©\seq showed that the expression of genes involved in multiple processes, including auxin©\related genes, was significantly altered in nab1. These results suggest that NAB1 functions in strigolactone biosynthesis and the regulation of shoot branching via an interaction with auxin transport.

Abstract (Browse 43)   |   Full Text
Plant glycosylphosphatidylinositol (GPI) anchored proteins at the plasma membrane©\cell wall nexus
Author: Trevor H. Yeats, Antony Bacic and Kim L. Johnson
Received: March 27, 2018         Accepted: April 16, 2018
Online Date: April 18, 2018
DOI: 10.1111/jipb.12659
                     
      
    

Approximately 1% of plant proteins are predicted to be post©\translationally modified with a glycosylphosphatidylinositol (GPI) anchor that tethers the polypeptide to the outer leaflet of the plasma membrane. While the synthesis and structure of GPI anchors is largely conserved across eukaryotes, the repertoire of functional domains present in the GPI©\anchored proteome has diverged substantially. In plants, this includes a large fraction of the GPI©\anchored proteome being further modified with plant©\specific arabinogalactan (AG) O©\glycans. The importance of the GPI©\anchored proteome to plant development is underscored by the fact that GPI biosynthetic null mutants exhibit embryo lethality. Mutations in genes encoding specific GPI©\anchored proteins (GAPs) further supports their contribution to diverse biological processes occurring at the interface of the plasma membrane and cell wall, including signaling, cell wall metabolism, cell wall polymer cross©\linking, and plasmodesmatal transport. Here, we review the literature concerning plant GPI©\anchored proteins in the context of their potential to act as molecular hubs that mediate interactions between the plasma membrane and the cell wall and their potential to transduce the signal into the protoplast and thereby activate signal transduction pathways.

Abstract (Browse 47)   |   Full Text
  Plant-pathogen Interactions
Leaf stage©\associated resistance is correlated with phytohormones in a pathosystem©\dependent manner
Author: You-Ping Xu, Lin-Hui Lv, Ya-Jing Xu, Juan Yang, Jia-Yi Cao and Xin-Zhong Cai
Received: February 13, 2018         Accepted: April 23, 2018
DOI: 10.1111/jipb.12661
                     
      
    

It has been reported in several pathosystems that disease resistance can vary in leaves at different stages. However, how general this leaf stage©\associated resistance is, and the molecular mechanism(s) underlying it, remain largely unknown. Here, we investigated the effect of leaf stage on basal resistance, effector©\triggered immunity (ETI) and nonhost resistance, using eight pathosystems involving the hosts Arabidopsis thaliana, Nicotiana tabacum, and N. benthamiana and the pathogens Sclerotinia sclerotiorum, Pseudomonas syringae pv. tabaci, P. syringae pv tomato DC3000, and Xanthomonas oryzae pv. oryzae (Xoo). We found evidence that leaf stage©\associated resistance exists ubiquitously in plants, but with varying intensity at different stages in diverse pathosystems. Microarray expression profiling assays demonstrated that hundreds of genes involved in defense responses, phytohormone biosynthesis and signaling, and calcium signaling, were differentially expressed between leaves at different stages. The Arabidopsis mutants sid1, sid2©\3, ein2, jar1©\1, aba1 and aao3 lost leaf stage©\associated resistance to S. sclerotiorum, and the mutants aba1 and sid2©\3 were affected in leaf stage©\associated RPS2/AvrRpt2+©\conferred ETI, while only the mutant sid2©\3 influenced leaf stage©\associated nonhost resistance to Xoo. Our results reveal that the phytohormones salicylic acid, ethylene, jasmonic acid and abscisic acid likely play an essential but pathosystem©\dependent role in leaf stage©\associated resistance.

Abstract (Browse 34)   |   Full Text
  New Technology
Multiplex gene editing in rice with simplified CRISPR©\Cpf1 and CRISPR©\Cas9 systems
Author: Mugui Wang, Yanfei Mao, Yuming Lu, Zhidan Wang, Xiaoping Tao and Jian-Kang Zhu
Received: March 23, 2018         Accepted: May 10, 2018
Online Date: May 15, 2018
DOI: 10.1111/jipb.12667
                     
      
    

We developed simplified single transcriptional unit (SSTU) CRISPR systems for multiplex gene editing in rice using FnCpf1, LbCpf1 or Cas9, in which the nuclease and its crRNA array are co©\expressed from a single Pol II promoter, without any additional processing machinery. Our SSTU systems are easy to construct and effective in mediating multiplex genome editing.

 

Abstract (Browse 36)   |   Full Text
  Molecular Ecology and Evolution
Tecia solanivora infestation increases tuber starch accumulation inPastusa Suprema potatoes
Author: Pavan Kumar, Etzel Garrido, Kun Zhao, Yi Zheng, Saleh Alseekh, Erandi Vargas-Ortiz, Alisdair R. Fernie, Zhangjun Fei, Katja Poveda and Georg Jander
Received: May 4, 2018         Accepted: June 7, 2018
Online Date: June 11, 2018
DOI: 10.1111/jipb.12675
                     
      
    

In response to infestation with larvae of the Guatemalan tuber moth (Tecia solanivora), some Solanum tuberosum (potato) varieties exhibit an overcompensation response, whereby the total dry mass of uninfested tubers is increased. Here, we describe early responses, within the first few days, of T. solanivora feeding, in the Colombian potato variety Pastusa Suprema. Non©\targeted metabolite profiling showed significant secondary metabolism changes in T. solanivora©\infested tubers, but not in uninfested systemic tubers. In contrast, changes in primary metabolism were greater in uninfested systemic tubers than in the infested tubers, with a notable 80% decline in systemic tuber sucrose levels within one day of T. solanivora infestation. This suggested either decreased sucrose transport from the leaves or increased sink strength, i.e. more rapid sucrose to starch conversion in the tubers. Increased, sucrose synthesis was indicated by higher rubicso activase and lower starch synthase gene expression in the leaves of infested plants. Elevated sink strength was demonstrated by 45% more total starch deposition in systemic tubers of T. solanivora©\infested plants compared to uninfested control plants. Thus, rather than investing in increased defense of uninfested tubers, Pastusa Suprema promotes deposition of photoassimilates in the form of starch as a response to T. solanivora infestation.

Abstract (Browse 9)   |   Full Text
Maintenance of species boundaries in three sympatric Ligularia (Senecioneae, Asteraceae) species
Author: Ningning Zhang, Yongpeng Ma, Ryan A. Folk, Jiaojun Yu, Yuezhi Pan and Xun Gong
Received: April 10, 2018         Accepted: May 31, 2018
Online Date: June 7, 2018
DOI: 10.1111/jipb.12674
                     
      
    

The key process in speciation concerns the formation and maintenance of reproductive isolating barriers between diverging lineages. Although species boundaries are frequently investigated between two species across many taxa, reproductive isolating barriers among multiple species (>2) that would represent the most common phenomenon in the nature, remain to be clarified. Here, we use double digest restriction©\site associated DNA (ddRAD) sequencing to examine patterns of hybridization at a sympatric site where three Ligularia species grow together and verify whether those patterns contribute to the maintenance of boundaries among species. The results based on the RAD SNP datasets indicated hybridization L. cyathiceps × L. duciformis and L. duciformis × L. yunnanensis were both restricted to F1s plus a few first©\generation backcrosses and no gene introgression were identified, giving rise to strong reproductive isolation among hybridizing species. Moreover, hybrid swarm simulation, using HYBRIDLAB, indicated the RAD SNP datasets had sufficient discriminatory power for accurate hybrid detection. We conclude that parental species show strong reproductive isolation and they still maintain species boundaries, which may be the key mechanism to maintain species diversity of Ligualria in the eastern Qinghai©\Tibetan Plateau and adjacent areas. Moreover, this study highlights the effectiveness of RAD sequencing in hybridization studies.

Abstract (Browse 24)   |   Full Text

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Online ISSN: 1744-7909 Print ISSN: 1672-9072 CN: 11-5067/Q