Takuya Suzaki

University of Tsukuba · School of Life and Environmental Sciences

Drought stress is a severe environmental issue that threatens agriculture at a large scale. PHYTOCHROMES (PHYs) are important photoreceptors in plants that control plant growth and development and are involved in plant stress response. The aim of this study was to identify the role of PHYs in the tomato cv. ‘Moneymaker’ under drought conditions. Th...

Root nodule symbiosis is promoted in nitrogen-deficient environments, whereas host plants cease the symbiosis if they can obtain enough nitrogen from their surrounding soil. In Lotus japonicus, recent reports indicate that two NODULE INCEPTION (NIN)-LIKE PROTEIN (NLP) transcription factors, LjNLP1 and LjNLP4, play important roles in the regulation...

During the course of plant evolution, leguminous and a few plants species have established root nodule symbiosis (RNS), one of the nitrogen nutrient acquisition strategies based on mutual interaction between plants and nitrogen-fixing bacteria. In addition to its useful agronomic trait, RNS comprises a unique form of plant lateral organogenesis; de...

Legumes have adaptive mechanisms that regulate nodulation in response to the amount of nitrogen in the soil. In Lotus japonicus, two NODULE INCEPTION (NIN)-LIKE PROTEIN (NLP) transcription factors, LjNLP4 and LjNLP1, play pivotal roles in the negative regulation of nodulation by controlling the expression of symbiotic genes in high nitrate conditio...

Heat stress (HS) is a prevalent negative factor affecting plant growth and development, as it is predominant worldwide and threatens agriculture on a large scale. PHYTOCHROMES (PHYs) are photoreceptors that control plant growth and development, and the stress signaling response partially interferes with their activity. PHYA, B1, and B2 are the most...

Leguminous plants produce nodules for nitrogen fixation; however, nodule production incurs an energy cost. Therefore, as an adaptive strategy, leguminous plants halt root nodule development when sufficient amounts of nitrogen nutrients, such as nitrate, are present in the environment. Although legume NODULE INCEPTION (NIN)-LIKE PROTEIN (NLP) transc...

Legumes utilize a shoot-mediated signaling system to maintain a mutualistic relationship with nitrogen-fixing bacteria in root nodules. In Lotus japonicus, shoot-to-root transfer of microRNA miR2111 that targets TOO MUCH LOVE, a nodulation suppressor in roots, has been proposed to explain the mechanism underlying nodulation control from shoots. How...

Legumes possess the autoregulation of nodulation (AON) pathway which is responsible for maintaining optimal root nodule number. In Lotus japonicus, AON comprises the CLE-HAR1-TML module, which plays an essential role in transmitting signals via root-to-shoot-to-root long-distance signaling. In addition to AON’s principal role of negatively regulati...

Arabidopsis SIZ1 encodes a SUMO E3 ligase to regulate abiotic and biotic stress responses. Among SIZ1 or mammalian PIAS orthologs, plant SIZ1 proteins contain the plant homeodomain (PHD) finger, a C4HC3 zinc finger. Here, we investigated the importance of PHD of Arabidopsis SIZ1. The ProSIZ1::SIZ1(ΔPHD):GFP was unable to complement growth retardati...

Legumes survive in nitrogen-limited soil by forming a symbiosis with rhizobial bacteria. During root nodule symbiosis, legumes strictly control the development of their symbiotic organs, the nodules, in a process known as autoregulation of nodulation (AON). The study of hypernodulation mutants has elucidated the molecular basis of AON. Some hyperno...

Legume-rhizobium symbiosis leads to the formation of nitrogen-fixing root nodules. However, externally applied chemical nitrogen fertilizers (nitrate and ammonia) strongly inhibit nodule formation and nitrogen fixation. Here, we isolated several rhizobial strains exhibiting a superior nodulation and nitrogen fixation with soybean at high nitrate co...

Transient protein expression is an effective tool to rapidly unravel novel gene functions, such as transcriptional activity of promoters and sub-cellular localization of proteins. However, transient expression is not applicable to some species and varieties because of insufficient expression levels. We recently developed one of the strongest agroin...

[This corrects the article DOI: 10.1371/journal.pgen.1007865.].

Nitrogen-fixing rhizobia and arbuscular mycorrhizal fungi (AMF) form symbioses with plant roots and these are established by precise regulation of symbiont accommodation within host plant cells. In model legumes such as Lotus japonicus and Medicago truncatula, rhizobia enter into roots through an intracellular invasion system that depends on the fo...

lan nodulation phenotype of later nodulation stages and inoculation of M. loti nodC mutants. (A) The numbers of sites of cortical cell proliferation (CCP) and of nodule primordia (NP), and mature nodules in DR5:GFP-NLS/WT MG-20 and in the DR5:GFP-NLS/lan plants at 45 dai (n = 11 plants). CCP was identified by GFP-NLS signals that were expressed und...

Close-up images showing effect of the lan mutation in early nodule development. (A and B) Nodule primordia formed on 4 dai DR5:GFP-NLS/WT MG-20 (A) and on 11 dai DR5:GFP-NLS/lan (B) roots. (C and D) Merged images of patterns of rhizobial invasion and auxin response of nodule primordia formed on 4 dai DR5:GFP-NLS/WT MG-20 (C) and on 11 dai DR5:GFP-N...

Complementation analysis. (A) Average nodule number in WT and the lan mutant with transgenic roots containing respective constructs at 14 dai (n = 17–22 plants). NP, nodule primrdia. (B-F) Representative transgenic hairy roots of WT MG-20 (B) or lan (C-F) constitutively expressing GUS (B and F), LjLAN (C), AtMED2 (D), LjLANΔC (E) at 14 dai. The det...

Patterns of calcium spiking. Transgenic hairy roots containing the nuclear-localized yellow-chameleon (YC2.60) construct were analyzed. Nod-factor (A and B) or water (C and D) were applied to WT MG-20 (A and C) and lan (B and D) roots. In this experimental condition, Nod factor treatment generated calcium spiking in 14/48 WT MG-20 and 29/104 lan ro...

Exon-intron structure of the LjLAN gene and the site of mutation in the lan mutant. Boxes indicate exons. Initiation codon (ATG) of LjLAN is marked in magenta. Splice (GT) and acceptor (AG) site of intron is marked in blue. Thick arrows indicate locations of primer sets used for RT-PCR analysis in Fig 4A. The position of introns in LjLAN in WT was...

LjLAN expression pattern. (A) RT-PCR analysis of the LjLAN gene. LjUBQ was used as the RNA loading control. The locations of primer sets used for PCR is shown in S5 Fig. cDNA was prepared from total RNAs roots (0), and in inoculated roots at 1, 7 and 14 dai. (B) Real-time RT-PCR analysis of LjLAN in lan and the LORE1-tagged line of lan (Plant ID: 3...

Primers used in this work. (XLS)

Map-based cloning of LjLAN. The lan locus was mapped using F2 population derived from a cross between lan and Gifu B-129 plants. 108 F2 plants that exhibited the nodulation-deficient phenotype were used for this analysis. Arrow indicates the LAN candidate gene (chr3.CM0112.280.r2.d) found in the L. japonicus genomic sequence database. The primers u...

LjLAN is a putative orthologue of AtMED2/29/32. (A) Phylogenetic tree of LjLAN-related proteins. Full-length amino acids sequences were compared and the tree was constructed by neighbor-joining methods. Numbers indicate bootstrap values. (B) Amino acid alignment of the LjLAN-related proteins. The amino acid residues with 100% homology among the pro...

Spatial expression patterns of LjLAN during nodulation. (A-E) GUS staining pattern of WT MG-20 transgenic hairy roots containing the ProLjLAN:GUS plus construct at 4 dai (A-D) and 9 dai (E). Closed and open arrowheads respectively indicate nodulation foci and curled root hair. Arrows indicate lateral roots. Scale bars: 1 mm (A, E); 100 μm (B-D). (T...

AM symbiosis phenotypes of LORE1-tagged lines of lan. (A and B) R. irregularis colonization ratio of hyphae (A) and arbuscules (B) at 21 dai. (n = 6 plants). Error bars indicate SD. (TIF)

The effect of the lan mutation on shoot and root growth. (A) WT MG-20 (left) and lan (right) plants at 14 days after germination (dag). (B and C) shoot (B) and primary root (C) length at 14 dag. Plants were grown in the soil that contained enough nutrients in the absence of rhizobia and AMF. (D and E) Root hairs phenotype of WT MG-20 (D) and lan (E...

Shoot and root growth of LORE1-tagged lines of lan. (A) WT Gifu (left) and 30008618 (right) plants at 14 days after germination (dag). (B and C) shoot (B) and primary root (C) length at 14 dag. Plants were grown in the soil that contained enough nutrients in the absence of rhizobia and AMF. Scale bar: 1 cm. Error bars indicate SD. (TIF)

Model for the position of LjLAN-mediated regulation in root nodule symbiosis. Perception of rhizobia-derived Nod factor by its receptors elicits Nod factor signaling. Consequently, calcium signaling is induced, which is decoded by LjCCaMK. LjCCaMK then activates LjCYCLOPS, which directly induces LjNIN expression. As normal calcium spiking pattern w...

Expression patterns of LjLAN and LjLAN LIKE. (A and B) Real-time RT-PCR analysis of LjLAN (A) and LjLAN LIKE (B) expression in reproductive and vegetative organs. Each cDNA sample was prepared from total RNA derived from the flower, leaf, stem, shoot apex, non-inoculated (-) and 1 dai (+) roots. (C) Real-time RT-PCR analysis of LjLAN expression in...

Nodulation phenotypes of LORE1-tagged lan lines and lan plants created by the CRISPR/Cas9 genome editing system. (A) A schematic diagram of LORE1 insertion site in the LORE1-tagged line of lan (Plant ID: 30008618). (B) Amino acid alignment of several truncated LjLAN used in this study. The amino acids sequence of LjLAN in 30008618 and two lan CRISP...

AM symbiosis phenotypes of lan cyclops double mutant. (A and B) R. irregularis colonization ratio of hyphae (A) and arbuscules (B) at 28 dai. (n = 8 plants). Error bars indicate SD. Columns with the same lower-case letter indicate no significant difference (Tukey’s test, P < 0.05). (TIF)

Legumes can survive in nitrogen-deficient environments by forming root-nodule symbioses with rhizobial bacteria; however, forming nodules consumes energy, and nodule numbers must thus be strictly controlled. Previous studies identified major negative regulators of nodulation in Lotus japonicus, including the small peptides CLAVATA3/ESR (CLE)-RELATE...

The expression of hundreds of genes is induced by low temperatures via a cold signaling pathway. ICE1, a MYC-type transcription factor, plays an important role in the induction of CBF3/DREB1A to control cold-responsive genes and cold tolerance. To elucidate other molecular factors, a yeast 2-hybrid screening was performed. Two MYC-type transcriptio...

Root nodule symbiosis is one of the best-characterized mutualistic relationships between plants-microbes symbiosis, where mainly leguminous species can obtain nitrogen sources fixed by nitrogen-fixing rhizobia through the formation of symbiotic organs root nodules. In order to drive this symbiotic process, plants need to provide carbon sources that...

Nitrogen is an indispensable inorganic nutrient that is required by plants throughout their life. Root nodule symbiosis (RNS) is an important strategy mainly adopted by legumes to enhance nitrogen acquisition, where several key processes required for the establishment of the symbiosis, are pleiotropically controlled by nitrate availability in soil....

Legumes and rhizobia establish symbiosis in root nodules. To balance the gains and costs associated with the symbiosis, plants have developed two strategies for adapting to nitrogen availability in the soil: plants can regulate nodule number and/or stop the development or function of nodules. Although the former is accounted for by autoregulation o...

Cold shock triggers an immediate rise in the cytosolic free calcium concentration ([Ca2+]cyt) in Arabidopsis thaliana and this cold-induced elevation of [Ca2+]cyt is inhibited by lanthanum or EGTA. It is suggested that intracellular calcium mainly contributes to the cold-induced [Ca2+]cyt response by entering into the cytosol. Two calcium-permeable...

Parasite infections cause dramatic anatomical and ultrastructural changes in host plants. Cyst nematodes are parasites that invade host roots and induce a specific feeding structure called a syncytium. A syncytium is a large multinucleate cell formed by cell wall dissolution-mediated cell fusion. The soybean cyst nematode (SCN), Heterodera glycines...

Root hairs result from the polar outgrowth of root epidermis cells in vascular plants. Root hair development processes are regulated by intrinsic genetic programs, which are flexibly modulated by environmental conditions, such as nutrient availability. Basic programs for root hair development were present in early land plants. Subsequently, some pl...

Nematode infection of plant roots is a paradigm of host–parasite interactions. Although nematodes can be labeled with fluorescent dyes, migration of the worms into the deep regions of host roots makes them difficult to track. Here we report the use of two fluorescent dyes, FM4-64 and SYBR green I, to intensely label the soybean cyst nematode (SCN)...

A major feature of embryogenesis is the specification of stem cell systems, but in contrast to the situation in most animals, plant stem cells remain quiescent until the postembryonic phase of development. Here, we dissect how light and metabolic signals are integrated to overcome stem cell dormancy at the shoot apical meristem. We show on the one...

Cell-to-cell communication, principally mediated by short- or long-range mobile signals, is involved in many plant developmental processes. In root nodule symbiosis, a mutual relationship between leguminous plants and nitrogen-fixing rhizobia, the mechanism for the autoregulation of nodulation (AON) plays a key role in preventing the production of...

Legumes and a few other plant species can establish a symbiotic relationship with nitrogen-fixing rhizobia, which enables them to survive in a nitrogen-deficient environment. During the course of nodulation, infection with rhizobia induces the dedifferentiation of host cells to form primordia of a symbiotic organ, the nodule, which prepares plants...

Significance Cell–cell communication is a prerequisite of multicellular development and noncell autonomous stem cell induction has been conserved during evolution. Cytoplasmic bridges, called plasmodesmata, which facilitate the exchange of molecules between neighboring cells, are a striking innovation for cell–cell signaling in plants. Here, we sho...

Legumes establish symbiotic associations with nitrogen-fixing bacteria (rhizobia) in root nodules to obtain nitrogen. Legumes control nodule number through long-distance communication between roots and shoots, maintaining the proper symbiotic balance. Rhizobial infection triggers the production of mobile CLE-RS1/2 peptides in Lotus japonicus roots;...

Root nodulation is a unique developmental process that predominantly occurs in leguminous plants. In this process, signaling initiated by symbiotic bacterial infection alters the fate of differentiated cortical cells and causes formation of new organs. Two qualitatively different regulatory events, namely bacterial infection and nodule organogenesi...

Many leguminous plants have a unique ability to reset and alter the fate of differentiated root cortical cells to form new organs of nitrogen-fixing root nodules during legume-Rhizobium symbiosis. Recent genetic studies on the role of cytokinin signaling reveal that activation of cytokinin signaling is crucial to the nodule organogenesis process. H...

Legume-rhizobium symbiosis occurs in specialized root organs called nodules. To establish the symbiosis, two major genetically controlled events, rhizobial infection and organogenesis, must be occur. For a successful symbiosis, it is essential that the two phenomena simultaneously proceed in different root tissues. Although several symbiotic genes...

Arbuscular mycorrhizal symbiosis (AMS) and root nodule symbiosis (RNS) are mutualistic plant-microbe interactions that confer nutritional benefits to both partners. Leguminous plants possess a common genetic system for intracellular symbiosis with AM fungi and with rhizobia. Here we show that CERBERUS and NSP1, which respectively encode an E3 ubiqu...

The phytohormones cytokinin and auxin are essential for the control of diverse aspects of cell proliferation and differentiation processes in plants. Although both phytohormones have been suggested to play key roles in the regulation of root nodule development, only recently, significant progress has been made in the elucidation of the molecular ge...

The interaction of legumes with N2-fixing bacteria collectively called rhizobia results in root nodule development. The number of nodules formed is tightly restricted through the systemic negative feedback control by the host called autoregulation of nodulation (AON). Here, we report the characterization and gene identification of TOO MUCH LOVE (TM...

Leguminous plants develop root nodules in symbiosis with soil rhizobia. Nodule formation occurs following rhizobial infection of the host root that induces dedifferentiation of some cortical cells and the initiation of a new developmental program to form nodule primordia. In a recent study, we identified a novel gene, TRICOT (TCO), that acts as a p...

During the course of evolution, mainly leguminous plants have acquired the ability to form de novo structures called root nodules. Recent studies on the autoregulation and hormonal controls of nodulation have identified key mechanisms and also indicated a possible link to other developmental processes, such as the formation of the shoot apical meri...

In leguminous plants, rhizobial infection of the epidermis triggers proliferation of cortical cells to form a nodule primordium. Recent studies have demonstrated that two classic phytohormones, cytokinin and auxin, have important functions in nodulation. The identification of these functions in Lotus japonicus was facilitated by use of the spontane...

Nodulation is a form of de novo organogenesis that occurs mainly in legumes. During early nodule development, the host plant root is infected by rhizobia that induce dedifferentiation of some cortical cells, which then proliferate to form the symbiotic root nodule primordium. Two classic phytohormones, cytokinin and auxin, play essential roles in d...

Despite the independent evolution of multicellularity in plants and animals, the basic organization of their stem cell niches is remarkably similar. Here, we report the genome-wide regulatory potential of WUSCHEL, the key transcription factor for stem cell maintenance in the shoot apical meristem of the reference plant Arabidopsis thaliana. WUSCHEL...

Establishment of adaxial-abaxial polarity is essential for lateral organ development. The mechanisms underlying the polarity establishment in the stamen remain unclear, whereas those in the leaf are well understood. Here, we investigated a rod-like lemma (rol) mutant of rice (Oryza sativa), in which the development of the stamen and lemma is severe...

The mechanism of floral organ specification is principally conserved in angiosperms, as demonstrated by the ABC model. By contrast, mechanisms that regulate the development of organs or structures specific to a group of species remain unclear. Grasses have unique inflorescence units, comprising spikelets and florets. In the genus Oryza (rice), the...

Accessions of wild rice species and African domesticated rice and their FOS1 haplotypes. (0.01 MB PDF)

Sequences of the FOS1 gene and FOS1 protein. (A) Nucleotides sequence corresponding to the coding region of the indica FOS1 gene. The nucleotide substituted in japonica is indicated in red. (B) Amino acid sequence of the indica FOS1 protein. The amino acid substituted in japonica is indicated in red. Amino acids in the putative active CLE peptide a...

Nucleotide changes or indels in FOS1 haplotypes. The FNP is located at the 69th position. Haplotype C is used as a reference. Synonymous substitution is indicated with light blue and nonsynonymous substitution with pink. Twelve nucleotides are deleted at positions 85–96 without a frameshift in haplotype H. Positions 358–393 correspond to the CLE do...

FON2 and FOS1 redundantly restrict stem cell proliferation in the FM in indica but not in japonica. See text for details. (0.00 MB PDF)

Accessions in WRC and their FOS1 haplotypes. (0.02 MB PDF)

Accessions in JRC and their FOSI haplotypes. (0.01 MB PDF)

Primers use in this study. (0.03 MB PDF)