3^rd International Conference on Plant Science & Physiology May 21-22, 2018 Osaka, Japan

Young Dae Choi has his expertise in soil chemistry. He has been working on plant nutrient and soil fertility management at the National Institute of Crop science in Korea for years. His research interests are the change of soil properties and soil management technology for sustainable upland crop cultivation in converted paddy field. Recent research subjects are assessment of long-term variability of soil environment by change of the usage pattern on paddy field and developing additional nitrogen fertilization method for yield increase in intensive cultivation of soybean at paddy field.

Recently, need of increasing upland crop cultivation in paddy field elevated due to growing importance of activating upland farming and overproduction of rice in South Korea. A yield of soybean decreased according to increase cultivation period in paddy field. The cause was widely known as soil organic matter content and soil nitrogen supply decrease. But paradoxical results existed. And the cause of yield decrease was also assumed that pH decrease according to cation leaching and phosphate availability decrease according to iron oxidation were related to. In order to prevent decreasing yield, it is necessary to identified the root cause. The objective of this study was to research for soil phosphate availability through investigating change of soil phosphorus distribution according to cultivation period of sorghum in paddy field. When converts paddy to upland, oxidation condition lasts and change of soil iron material occurs. Because high phosphorus adsorption coefficient lasted due to change of oxidation state in soil iron but soil organic phosphorus decreased exponentially, it was assumed that soil phosphate availability and crop productivity was limiting factor. This suggests that the limiting factor of soil fertility can be changed from C, N to P and change of soil management practices is required depending on the soil characteristics before cultivating upland crop such as amorphous iron content and phosphorus adsorption coefficient in converted paddy field.

Yang Gyu Ku, he is working in the department of Horticulture Industry, Wonkwang University, Republic of Korea, and it is a Good Agriculture Management Center, Wonkwang University.

Under abnormal climate conditions, due to the climate change, vegetable crops grown in the open field may encounter unfavorable growth conditions, resulting in physiological disruption, which may lead to economic damage. Chinese cabbage grown in the autumn season is confronted with drought conditions in a certain period, especially at an early growth stage after planting. The effects of drought stress on plant growth characteristics as well as carotenoid, free amino acid and proline contents were investigated in Chinese cabbage. The plant material used in this study was “Bool-am No. 3” Chinese cabbage. Chinese cabbage seeds were germinated, and all seedlings were transplanted into plastic containers (22 cm diameter×23 cm high) containing a commercial growth medium, followed by control and drought treatments. The soil water content was measured and maintained at 10% for the drought-stressed plants and at 30% for the control plants, for 3 weeks. The results showed that plant growth parameters were lower in the drought-stressed plants than in the control plants. The carotenoid and proline contents were unaffected in Chinese cabbage by drought treatment. The total free amino acid content tended to decrease in both drought-stressed and control plants over time; however, the decrease was greater in the drought-treated plants than in the control plants over the three week period. Consequently, the total free amino acid content was found to be lower in the drought-stressed plants than in the control plants.

Ick-Hyun Jo has completed his PhD at the age of 34 years from Chungbuk National University and postdoctoral studies from National Institute of Horticultural and Herbal Science (NIHHS) in South Korea. He is the public agricultural research worker, a Rural Development Administration (RDA). He has published more than 48 papers in reputed journals and serving as an editorial board member for Medical Crop Science Journal.

Ginseng is a valuable crop that is grown by long-term cultivation in the same field. As it prefers a cool climate for optimal growth, new sites of cultivation can be adversely affected by rising temperatures due to global warming. Ginseng is sensitive to high temperature induced injury that can affect both quality and yield of the crop. Although selection of ginseng varieties that are resistant to high temperatures is important, it is not possible to use genetic methods for such selection as molecular markers associated with responses to high temperature stress are largely unknown. Here, we used full-length transcripts of ginseng marker genes to identify those involved in photosynthesis rates in ginseng seedlings and, subsequently, monitored their expression in response to a high temperature stress. Initially, the changes in chlorophyll fluorescence induction kinetics (OJIP) and FV/FM values were monitored. The results showed a reduction in photosynthetic efficiency on heat treatment (35°C) starting at 48 h. At 35°C for 48 h, ginseng seedlings showed low photosynthetic efficiency as evidenced by changes in chlorophyll fluorescence induction kinetics (OJIP) and Fv/Fm in comparison to a control plant (25°C). The FV/FM value of the control was 0.768, whereas that of the high-temperature treated plants ranged from 0.501 to 0.718. Transcript levels for 20 heat shock related genes were more strongly expressed in high-temperature treated ginseng leaves compared to 21 Arabidopsis genes expressing after heat stress. Overall, our results identified 5 genes in ginseng showing strongly altered expression levels, KG_ISO_015287, KG_ISO_022801, KG_ISO_038129, KG_ISO_045346, and KG_ISO_093311; these genes will be of value for use as selection markers in breeding strategies to develop high-temperature resistance in ginseng.

Satoru Nakashima is Professor of Physical Geochemistry at Osaka University and has been developing non-destructive evaluation methods of earth, planetary and environmental materials and quantifying their changes with time. In particular, he pioneered spectro-colorimetry of rocks and soils and has been applying it to degradation of rocks. He has recently developed handy spectro-colorimeters in the visible to near infrared wavelength range and now is using them for measuring ripening, aging and degradation processes of plants (vegetables and fruits) and meats. He is aiming at founding a Non-Profit Organization on Earth’s Environmental Health including safety of plants and foods, after his retirement form Osaka University in 2 years. He wishes to collaborate with experts from all over the world to maintain the health of our natural environment.

Ripening, aging and degradation processes of foods are essential for evaluating conditions and safety of foods. The timing of harvesting vegetables/fruits is often empirical depending on farmers’ experiences. After the harvest, some show further ripening before aging and degradation. Despite some data on high temperature (> 50oC) behavior of foods during drying and cooking conditions, changes with time of foods at environmental temperatures around 25oC have not been studied quantitatively. In this study, a handy visible – near infrared spectrometer (PRISMO MIRAGE) have been developed and applied to monitor color and spectral changes with time of some vegetables and fruits either under natural outdoor conditions (Ripening : 5-35oC) or in containers (Aging/Degradation: 15-35oC). Changes with time in a* color values (reddishness) and in peak heights at 675 nm in visible spectra are analyzed for determining the first order decrease rates of a* and chlorophylls, respectively. These rate constants are plotted in Figure 1 together with some literature data on food drying processes. Decrease rates of a* color value during the final degradation of tomato at around 20oC appears to be on the linear trend from those for drying of green peas at 70-100oC (Figure 1). The decrease rates of lycopene/carotenoid for tomato pure during drying are also on the similar trend. Increase rates of a* value during ripening (green to red) of bell pepper at 30oC are also close to these trends. Decrease rates of chlorophylls by 675 nm peak heights for the same ripening processes of bell pepper is slower than the a* increase rates but close to the extrapolation of chlorophyll decrease rates during bell pepper drying at 40-70oC. The chlorophyll decrease rates are considered to control some of the ripening and degradation processes of vegetables and fruits.

Ms. Tee Yei Kheng is a research officer in Malaysian Cocoa Board since 2013 and currently, she is also a PhD candidate in Universiti Putra Malaysia (UPM). She has the research interests in plant physiology and precision agriculture. Ms. Tee is also the Head of Project for a research funding under 11th Malaysian Plan (2016-2020) with 10 research projects have been carried out to study the effects of climate changes on cocoa productivity. Despite that, she has the interests in applying Geographical Information System (GIS) and spectral reflectance of cocoa in response to nutrient deficiency and plant stress through precision cocoa management which grant her another research funding under 11th Malaysian Plan for 5 years (2016-2020). She was the first Borlaug Fellow from Malaysia in 2015 to join The Norman E. Borlaug International Agricultural Science and Technology Fellowship Program. This program was supported by WCF and the U.S. Department of Agriculture Foreign Agricultural Service.

The detection of pigments in cacao pods together with colourless flavonoids serves as a useful indicator for pod maturity using a fast and non-destructive multiparametric fluorescence sensor. In this study, the contents of anthocyanin, flavonol, chlorophyll and nitrogen balance of five cacao genotypes (DESA1, KKM22, KKM25, MCBC1 and PBC221) were determined monthly (1-5 months) after flower pollination. There were significant differences (P≤0.05) observed between the interaction of five different cacao clones and pod development periods in flavonol, chlorophyll and nitrogen balance contents. As pods developed, anthocyanin and flavonol accumulated while the content of chlorophyll decreased only when pod matured with nitrogen balance showed a decreasing trend in cacao pods. Among these clones, as expected, natural red appearance in cacao pods of DESA1 showed significantly highest index of anthocyanin (0.637), following by KKM22 (0.255). In addition, there was no significant difference observed in KKM25, MCBC1 and PBC221 for anthocyanin content. During pod development, MCBC1 showed the least content in flavonol (P≤0.05) and the chlorophyll contents in KKM22 and MCBC1 were lower compared to other clones. UPLC-QTOF analysis showed that major components found at the cacao peel extracts of the pods consisted of flavonoid and procyanidin which are commonly found in cacao beans. Besides phenolic compounds, the presence of methyl xanthine (theobromine and caffeine) was found in cacao peel. As a conclusion, non-destructive fluorescence-based indices can be used to measure the pigments and flavonoids in cacao which can provide valuable non-destructive indicators for cacao pod maturity across different cacao cultivars.

Qianyu Jin has his expertise in rice high yield, mechanized cultivation technology and nitrogen utilization. Recently, he studies the rice productivity and economic benefit of triple cropping systems in paddy field in northern Zhejiang plain, and also investigates the mechanisms of drought resistance in different rice varieties and specific expression of QTL for related agronomic characters under water Stress.

N can be easily transported from old organs to developing organs for reutilization. N remobilization between organs is important for high nitrogen use efficiency (NUE) at whole-plant level. Two hybrid rice cultivars japonica ‘Yongyou 538’ and indica ‘Zhongzheyou 1’ were hydroponically cultivated at low N (LN, 0.71 mM) and sufficient N (SN, 2.86 mM). The imposition of water stress, which was induced by 100 g•L-1 PEG 6000, resulted in an increase of NUE in ‘Yongyou 538’, but a reduction in ‘Zhongzheyou 1’. Water stress reduced nitrate and ammonium uptake and accumulation in ‘Yongyou 538’; whereas nitrate and ammonium uptake in ‘Zhongzheyou 1’ was not significantly affected. Contrary to ‘Yongyou 538’, ‘Zhongzheyou 1’ accumulated more ammonium in roots under water stress. In addition, water stress caused an increase in catabolism of carbon in roots of ‘Zhongzheyou 1’, as indicated by increased root activity, constant pyruvate kinase activity and sucrose concentration, and reduced total carbon. The degradation of protein was also augmented in ‘Zhongzheyou 1’. In contrast, the consumption of assimilates in ‘Yongyou 538’ was significantly inhibited, allowing more carbon stored in roots. Furthermore, water stress resulted in a significant increase in N allocation in root at SN. NUE was positive correlated with the percentage of N allocated in roots (r=0.723, n=32, p<0.01), but negatively correlated with the percentage of N allocated in leaves (r=-0.756, n=32, p<0.01). The results indicate that attenuation of root catabolic activity under water stress reduces nitrogen uptake and enhances the accumulation of carbon and nitrogen in roots, subsequently improves NUE at whole-plant level.

Eri Yamakita is a graduate student of Osaka University. She had majored in both biology and physics as an undergraduate and is interested in interactions between plants and environments, especially by using non-destructive evaluation methods. Her master thesis was on water retention ability of pectin, which is one of the polysaccharides in the plant cell wall. For her doctoral studies, she is examining interactions between rocks and mosses as the first biota growing on rocks.

In autumn, some species of plants change colors of leaves from green to red or yellow. Although this phenomenon is familiar to us, especially in Japan, color changing processes have not been fully understood. One of the problems is that extraction experiments are needed to measure changes in the chemical components such as pigments in leaves. Therefore, it is almost impossible to measure changes with time of chemical components in the same leaf during its color change. In this study, a handy spectro-colorimeter (PRISMO MIRAGE) have been developed and applied to monitor color and visible spectral changes with time of leaves of Acer palmatum, Japanese maple (Iroha Momiji). Two branches under different sunshine conditions in the Osaka university campus were chosen and 8 leaves are measured once per day in the morning from October 24 to December 7, 2016. Visible reflectance spectra of leaves changed with time during their color changes (Fig. 1). Green leaves show a strong absorption band around 670 nm due to chlorophyll. During their color changes from green to red, the 670 nm band decreased and a band around 550 nm appeared and increased with time. This 550 nm band is due to anthocyanin. Concentrations of chlorophyll and anthocyanin were calculated by using spectral reflectance values (Gitelson et al., 2009). They are plotted in Fig. 2 with a color scale corresponding to a* value (reddishness). Fig. 2 shows that the reddish colors are determined not only by anthocyanin concentrations but also by chlorophyll concentrations. In fact, our studies with other plants indicate stronger correlations of a* value with the chlorophyll concentrations than anthocyanin ones. Color changes of leaves can be controlled mainly by chlorophyll degradation associated with formation of anthocyanin.

Hansong Dong is working as a professor in Plant Growth and Defense Signaling Laboratory, College of Plant Protection, Nanjing Agricultural University, Nanjing, China.

Recently we elucidated that tobacco TTG2 cooperates with ARF8 to regulate the vegetative growth and seed production. Here we show that TTG2 and ARF8 control flower colorization by regulating the expression of ANS and DRF genes, which function in anthocyanin biosynthesis. Genetic modifications that substantially altered expression levels of the TTG2 gene and production quantities of the TTG2 protein were correlated with flower development and colorization. Degrees of flower colorization were increased by TTG2 overexpression but decreased by TTG2 silencing in coincidence with high and low concentrations of anthocyanins in flowers. Of five genes involved in the anthocyanin biosynthesis pathway, only ANS and DRF were TTG2-regulated and displayed enhancement and diminution of expression with TTG2 overexpression and silencing, respectively. The floral expression of ANS and DRF also needed a functional ARF8 gene as ANS and DRF expression was attenuated by ARF8 silencing, which concomitantly diminished the role of TTG2 in anthocyanin production. While ARF8 required TTG2 to be expressed by itself and to regulate ANS and DRF expression, the concurrent presence of normally functional TTG2 and ARF8 was critical for the floral production of anthocyanins and for flower colorization as well. Our data suggest that TTG2 cooperates with ARF8 to control degrees of flower colorization by regulating the expression of ANS and DRF, which are involved in the anthocyanin biosynthesis pathway. ARF8 depends on TTG2 to regulate the floral expression of ANS and DRF with the positive effects on anthocyanin production and flower colorization.

Xiaochen Chen is a Phd student in Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, Jiangsu Province, China.

Pathogenic Gram-negative bacteria interact with their eukaryotic hosts by deploying the type III translocon. The translocon compositions, the number and biochemical characteristics of type III translocators in animal-pathogenic bacteria have been well elucidated, but not for plant-pathogenic bacteria. With extensive studies on biological functions of the Hpa1 protein secreted by the type III secretion system in Xanthomonas oryzae pv. oryzae (Xoo), we showed that Hpa1 is a type III translocator based on measurements of two proteins categorized as transcription activator-like (TAL) effector. Hpa1 was functionally associated with the TAL effector PthXo1 or AvrXa10 by genetic analysis of the wild-type Xoo strain and related mutants or recombinant strains. Inoculation experiments suggested that Hpa1 is required not only for the virulent role of PthXo1 in the susceptible rice variety Nipponbare, but also for the avirulent function of AvrXa10 on the resistant rice variety IRBB10. Hpa1 is unrelated to the secretion of PthXo1 and AvrXa10 out of bacterial cells. However, Hpa1 is critical for both TAL effectors to be translocated from bacterial cells into the cytosol of rice cells based on replicate experiments performed on the susceptible and resistant varieties, respectively. Hpa1-mediated translocation of PthXo1 is coincident with induced expression of rice SWEET11 gene regulatory target of PthXo1, resulting in the occurrence of the bacterial blight disease in the susceptible rice variety. By contrast, the immune hypersensitive response is induced in agreement with induced expression of rice Xa10 gene, which is the target of AvrXa10, only when AvrXa10 is translocated from bacteria into cells of the resistant rice variety. All the virulent or avirulent performances of the TAL effectors are nullified by directed mutation that removes the α-helix motif from the Hpa1 sequence. The effect of the directed mutation suggests that Hpa1 depends on its α-helical motif to fulfil the translocator function.

Ping Li is a Phd Student in College of Plant Protection, Nanjing Agricultural University, Nanjing, China.

Small non-coding RNA (sRNA) short sequences regulate various biological processes in all organisms, including bacteria that are animal or plant pathogens. Virulent or pathogenicity-associated sRNAs have been increasingly elucidated in animal pathogens but little is known about similar category of sRNAs in plant-pathogenic bacteria. This is particularly true regarding rice bacterial blight pathogen Xanthomonas oryzae pathovar oryzae (Xoo) as studies on the virulent role of Xoo sRNAs is very limited at present. The number and genomic distribution of sRNAs in Xoo were determined by bioinformatics analysis based on high throughput sequencing (sRNA-Seq) of the bacterial cultures from virulence-inducing and normal growth media, respectively. A total of 601 sRNAs were identified in the Xoo genome and 12 virulent sRNA candidates were screened out based on significant differences of their expression levels between the culture conditions. Based on genetic analysis of Xoo ΔsRNA mutants generated by deletion of the 12 single sRNAs, trans217 and trans3287 were characterized as virulent sRNAs. They are essential not only for the formation of bacterial blight in a susceptible rice variety Nipponbare but also for the induction of hypersensitive response (HR) in nonhost plant tobacco. Xoo Δtrans217 and Δtrans3287 mutants fail to induce bacterial blight in Nipponbare and also fail to induce the HR in tobacco, whereas, genetic complementation restores both mutants to the wild type in the virulent performance and HR induction. Consistently, secretion of a type III effector, PthXo1, is blocked in Δtrans217 or Δtrans3287 bacterial cultures but retrieved by genetic complementation to both mutants. The genetic analysis characterizes trans217 and trans3287 as pathogenicity-associated sRNAs essential for the bacterial virulence on the susceptible rice variety and for the HR elicitation in the nonhost plant. The molecular evidence suggests that both virulent sRNAs regulate the bacterial virulence by targeting the type III secretion system.

Yiqun Hu, a PhD of Plant Protection College, Nanjing Agricultural University majors in plant defense signaling. Hu has her expertise in evaluation and passion in improving plant resistance for Gram-negative pathogen, Xanthomonas. The interaction between plant and pathogen is complicated process, with various signaling pathway. Too many unsolved mysteries, she will continue to try to reveal the mysteries of life science.

Varieties of Gram-negative bacterial pathogens infect their eukaryotic hosts by deploying the type III translocon to deliver effector proteins into the cytosol of eukaryotic cells. The translocon is hypothetically assembled by bacterial translocators in associations with the assumed receptors situated on eukaryotic plasma membranes. By carrying out SUB-Y2H assays with multiple controls, we clearly detected a direct interaction between Hpa1 and OsPIP1;3, a rice aquaporin, plasma membrane intrinsic protein. The interaction was confirmed by co-immunoprecipitation (Co-IP). Furthermore, the OsPIP1;3-Hpa1 interaction was monitored by YFP bimolecular fluorescence complementation (BiFC). In rice protoplasts, the OsPIP1;3-Hpa1 interaction was localized to PMs, where the BiFC signal was colocalized with the PM marker, FM4-64. In tobacco Nicotiana benthamiana leaves, Hpa1 was localized to PMs and interacted with the introduced OsPIP1;3. These findings indicate that Hpa1 and OsPIP1;3 directly interact with each other at plant PMs. The primary roles of PIPs in substrate transport across PMs are executed based on their topological structures. In the current model, PIPs consist of six α-helical transmembrane (TM) domains (TM1-TM6) that are tilted along the plane of the PM and are linked one to the other by five connecting loops (LA-LE). Hpa1 interacts with OsPIP1;3, but not with OsPIP1;1 and OsPIP1;2 (Fig. 1a). Therefore, either OsPIP1;1 or OsPIP1;2 is pertinent for site and fragment substitutions with OsPIP1;3 to look for Hpa1-interacting motifs in the OsPIP1;3 sequence. With this idea, we initially performed a series of site-directed mutations within LA, LC, and LE at amino acid residues that are different between OsPIP1;3 and OsPIP1;2 between OsPIP1;3 and OsPIP1;1. Unfortunately, none of site substitutions affected OsPIP1;3 interaction with Hpa1. Then, we turned to create substitutive proteins by switching each of the six extramembrane-related regions between OsPIP1;3 and OsPIP1;1 and we find LE of OsPIP1;3 determines its interaction with Hpa1.

Kiyuol Jung is a soil scientist at National Institute of Crop Science, Rural Development Administration (RDA) in Republic of Korea. Kiyuol Jung received his PhD degree in in soil science from Gyeongsang National University. Currently, he conducts researches on water management practices for field crop production in upland and paddy fields. He has contributed to improve water use efficiency, crop yield and plant functional compounds for soybean, sesame, and sorghum by groundwater control system, trenchless subsurface drainage of paddy fields, and subsurface drip irrigation systems.

The farmers have been using irrigation techniques through manual control which farmers irrigate lands at regular intervals. Automatic irrigation systems can be programmed to provide automatic irrigation to the plants which helps in saving money and water and to discharge more precise amounts of water in a targeted area, which promotes water conservation. The objective of this study was to determine the possible effect of automatic irrigation systems based on soil moisture on soybean growth. This experiment was conducted on an upland field with sandy loam soils in Department of Southern Area Crop, NICS, RDA. The study had three different irrigation methods; sprinkle irrigation (SI), surface drip irrigation (SDI) and fountain irrigation (FI). SI was installed at spacing of 7×7 m and 1.8m3/hr as square for per irrigation plot, a lateral pipe of SDI was laid down to 1.2 m row spacing with 2.3 L h-1 discharge rate, the distance between laterals was 20 cm spacing between dripper sand FI was laid down in 3 m interval as square for per irrigation plot. This automatic irrigation system had valves to turn irrigation on/off easily by automated controller, solenoids and moisture sensor which were set the reference level as available soil moisture levels of 30% at 10 cm depth. The efficiency of applied irrigation was obtained by dividing the total water stored in the effective root zone to the applied irrigation water. Results showed that seasonal applied irrigation water amounts were 60.4 ton 10a-1(SI), 47.3 ton 10a-1 (SDI) and 92.6 ton 10a-1 (FI), respectively. This system saved a large quantity of water by 27.5% and 95.6% compared to SI, FI system. The average soybean yield was significantly affected by different irrigation methods. The soybean yield by different irrigation methods were 309.7 kg 10a-1 from SDI 282.2 kg 10a-1 from SI, 289.4 kg 10a-1 from FI, and 206.3 kg 10a-1 from control, respectively. SDI resulted in increase of soybean yield by 50.1%, 7.0% 9.8% compared to non-irrigation (control), FI and SI, respectively. Therefore, the automatic irrigation system supplied water only when the soil moisture in the soil went below the reference. Thus the system is efficient and compatible to changing environment. In conclusion, improving automatic irrigation system can contribute greatly to reducing production costs of crops and making the industry more competitive and sustainable.