12:10 - 12:40 Registration

12:40 - 12:45 Welcome speech

Dr. Yasuyuki Kubo

Dean of Faculty of Agriculture, Setsunan University

12:45 - 13:00 Opening remarks from organizer

Dr. Shigeyuki Tanaka

Setsunan University

13:00 - 13:50 Keynote: Plant root endophyte

Disentangling programmed cell death (PCD) in plant root-fungal interactions

Dr. Alga Zuccaro

University of Cologne, Germany

Programmed cell death (PCD) in plants is a fundamental cellular process that can be triggered during developmental programs and by biotic and abiotic stresses. An active cell death process is integral to Arabidopsis root cap differentiation. Acquisition of cell death competence depends on the root cap-specific transcription factor ANAC033/SOMBRERO (SMB3). Cell death is followed by cell-autonomous corpse clearing involving the senescence-associated nuclease BFN1. Based on the observation that the beneficial fungal root endophyte Serendipita indica down-regulates BFN1 at the onset of the host-cell death colonization phase, we analysed the role of SMB3 and BFN1 in fungal root colonization. Due to the absence of a functional plant nuclease, knock-out mutation of bfn1 or smb3 results in accumulation of host cell corpses and enhanced intra- and extra-radical fungal colonization. These results emphasize the importance of root cap differentiation in plant-microbe interactions and lead to the proposition of a mechanism by which S. indica manipulates developmental programmed cell death (dPCD) in Arabidopsis roots by down-regulating the nuclease BFN1 to enhance fungal colonization through an excess of nutrients in the form of uncleared cell corpses.

13:50 – 15:00 Session 1: Genomics and evolution

Visual integrative omics of fungi

Dr. Shingo Miyauchi

Okinawa Institute of Science and Technology Graduate University, Japan

The era of integrative omics has come. Over 2,000 fungal genomes have become available on MycoCosm since the US Department of Energy Joint Genome Institute (JGI) began the 1000 Fungal Genomes Project. Using this resource, recent international collaborative efforts have revealed genomic trends of mycorrhizal fungi. However, there are challenges for analyzing data from high throughput technologies due to the large size and highly dimensional nature. Data visualization can be one of the ways to tackle the difficulty. We have been developing creative analytical tools focusing on dimension reduction using machine leaning and data visualization, which together facilitate biological interpretation. Our visual omics platform enables the integration of different omics data and the generation of publication quality graphics (https://www.researchgate.net/project/Visual-integrative-omics-platform). Our innovative methods help biologists analyze big data from high-throughput technologies. The tools have been a driver of fungal genomics research, which have contributed to 22 publications in the last seven years.

How the plant genome activates brand-new gene sequences: A fundamental mechanism for horizontal-gene transfer and evolution.

Dr. Junichi Obokata

Setsunan University, Japan

Horizontal gene transfer can occur between phylogenetically distant organisms, such as prokaryotes and eukaryotes. In these cases, how do translocated gene sequences acquire transcriptional activity, although a large difference lies between the transcription machinery of their original and new host genomes? To investigate the transcriptional activation process of horizontally transferred coding-sequences in the plant genome, we randomly introduced promoterless reporter sequences into the genome of cultured Arabidopsis thaliana cells and performed a genome-wide "transgene localization vs. expression" scan. From this survey, we found that the transcriptional activation of the inserts occurs all over the genome independently of the sequence context and chromatin landscape. Chromatin remodeling that affords transcription initiation was induced in response to the insertion events of the coding sequence, and quite new transcription start sites (TSS) emerged about 100 bp upstream of the coding sequences. We termed this new type of transcriptional activation phenomenon as de novo transcription. This remodeling state of the chromatin was inherited to the next generation, as has been demonstrated by studies in transgenic plants. In this talk, I introduce our findings and characteristics of de novo transcription and refer to its possible relevance in horizontal gene transfer and eukaryotic genome evolution.

15:00 – 15:30 Coffee break

15:30 – 16:40 Session 2: Plant disease and defense responses

Front line of plant defense-Apoplastic Immunity

Dr. Lay-sun Ma

Academia sinica, Taiwan

Cell-surface receptors and hydrolytic enzymes/defense molecules safeguard plant apoplasts to prevent the invasion of pathogenic microbes. Adapted pathogens have developed diverse counterattack strategies to breach the front line of plant defense. One of the strategies is to convert cell wall component chitin to chitosan to evade plant perception and disarm chitin-triggered immune responses. However, whether plants have evolved factors to counteract this evasion mechanism remains obscure. Using the maize-Ustilago maydis pathosystem as our model system, we discovered a maize secretory DUF-26 domain-containing protein (AFP1) modulates fungal cell surface chitin level. AFP1 binds to multiple sites on the cell surface of U. maydis to inhibit the budding and growth of sporidial cells, prevent spore germination, and eventually impair fungal viability in a pH-dependent manner. The findings that mannose-binding defective mutant of AFP1 loses the binding ability, and the deletion of O-mannosyltransferase 4 (pmt4) affects AFP1 binding to Δpmt4 cells, and such reduced binding correlates with reduced antifungal activity, suggesting that the targets of AFP1 are mannosylated proteins. Here, we will discuss how maize AFP1 modulates chitin metabolism to inhibit the growth of fungal cells.

Friend or foe? : The battle between "good and bad" fungi in the rhizosphere

Dr. Yuichiro Iida

Setsunan University, Japan

The soil-borne pathogen Fusarium oxysporum is a facultative fungus that causes economically important losses in a wide range of crops. Intraspecific variants of the fungus, called formae speciales (f. sp.), cause wilting symptoms (Fusarium wilt disease) on over 100 plant species. Hyphae of F. oxysporum penetrate the roots and invade the vascular system during the infection. Certain nonpathogenic strains of F. oxysporum are known to protect crops against pathogenic F. oxysporum. Their main modes of action vary and depends on the strain. To elucidate the molecular basis for biocontrol by nonpathogenic F. oxysporum against pathogenic F. oxysporum, we generated mutants that lost pathogenicity and assessed the biocontrol activity of pretreatment of plants with these nonpathogenic strains against the parental strain. We found that the biocontrol activity of nonpathogenic strains that grow epiphytically on the root surface mainly depends on their extensive colonization of the root surface and outcompeting pathogens for nutrients. Since nonpathogenic strains never compete with themselves for nutrients, and nutrient competition occurs only against strains that are pathogenic to plants, nonpathogenic strains might recognize pathogenic strains via virulence factors such as effector proteins or secondary metabolites secreted from pathogenic strains in rhizosphere.

16:40 – 17:50 Session 3: Plant growth and physiology

Molecular Physiological Characterization of Salinity Tolerance in Rice for Sustainable Agriculture

Dr. Akihiro Ueda

Hiroshima University, Japan

Excess accumulation of salts in soils causes salinity stress, which adversely affects crop production. Salinity stress occurs mainly in arid and semi-arid regions by poor precipitation and in coastal regions by intrusion of sea water. According to the FAO report, 20% of cultivated area are affected by high salinity and this area is increasing year by year because reclamation of salinized fields is quite difficult. As high salinity is known as a multicomponent stress, crop plants suffer from dehydration (osmotic stress) and disruption of ion homeostasis (ionic stress) under salinity stress. Long term salinity stress also leads to accumulation of reactive oxygen species in plant cells (oxidative stress). Alkaline salts accumulation raises soil pH and affects availability of essential nutrients in soils (nutrient stress). To overcome salinity stress, our group has been focusing on understanding physiological responses of crop plants to high salinity. Screening of divergent rice collections identified some tolerant varieties and revealing the mechanisms of salinity tolerance in rice would provide useful insight into developing salinity tolerant rice varieties.

Does a large amount of mineral nutrients secure crop production? -Molecular mechanisms of manganese toxicity in crop plants-

Dr. Daisuke Takagi

Setsunan University, Japan

Terrestrial plants require 14 mineral elements for their growth and reproduction. To maintain crop production, chemical fertilizers are constantly applied to agricultural soil. Owing to chemical fertilizers, crop production is actually increasing in the world. However, the applied mineral elements are not entirely utilized for crop production in some crop fields. Therefore, crop production could unconsciously deposit mineral elements in the soil. Excess amounts of essential mineral nutrients cause toxic effects on crop plants. This phenomenon is termed mineral toxicity. As well as a physiological response to mineral deficiency, crop plants show diverse responses to mineral toxicity depending on each mineral element. Recently, we investigated the effects of manganese toxicity in rice plants, and we found that the CO2 assimilation rate was lowered by stomatal closure, and both carbon anabolic and catabolic activities were decreased under excessive manganese application conditions. In addition to stomatal dysfunction, we found that the leaf IAA concentration was significantly decreased and auxin-responsive gene expressions also showed IAA-deficient responses in leaves under excess manganese conditions. For deeper interpretations of the molecular mechanisms of manganese toxicity, we continue to study the physiological effects of excess Mn on crop plants. Here, I discuss a strategy how to breed tolerant crops to excessive manganese based on our recent advances.

17:50-17:55 Closing remarks

18:15- Mixer