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In the present study Screening of salt tolerance potential of a panel of Vietnamese rice landraces at seedling stage, thirty three Vietnamese rice landraces at seedling stage were evaluated for their salt tolerance at ve salinity levels of 0 mM, 100 mM, 150 mM, 200 mM, and 250 mM NaCl. Plants were grown in hydroponics with salt application at the fourth leaf stage.
Journal of Vietnam Agricultural Science and Technology - No.1(3)/2018 should be made to enhance breeding for salt tolerant rice adapting on saltwater intrusion conditions Farmers should be trained on appropriate soil and water management measures, testing salinity and using salt tolerant rice varieties Further experiments need to be implemented for more crop seasons to identify scienti c results for encouragement of applying advanced technology such as new rice varieties and cultivation technique in similar ecological regions in the Red River Delta In addition, it is important to improve the irrigation infrastructure to increase the availability of fresh water for ushing out salts Under low rainfall periods, fresh water use for irrigation is limited and hence, it is a constraint REFERENCES Dasgupta S, Laplante B, Meisner C, Wheeler D, Yan J, 2007 e Impact of Sea Level Rise on Developing Countries: A Comparative Analysis World Bank Policy Research Working Paper No 4136 Dasgupta S, Laplante B, Murray S, Wheeler D., 2010 Exposure of developing countries to sea-level rise and storm surges Climatic Change DOI 10.1007/ s10584-010-9959-6 MONRE, 2012 Vietnam climate change and seas level rise Natural Resources and Environment publishing house Ministry of Natural Resources and Environment Hanh, P.T.T and Furukawa, M., 2007 Impact of sea level rise on coastal zone of Vietnam. Bulletin-college of Science University of the Ryukyus, 84, pp.45 Vien, T.D., 2011 Climate change and its impact on agriculture in Vietnam. Hanoi University of Agriculture, J Issaas, 17(1), pp.17-21 Zeidler, R.B., 1997 Continental shorelines: climate change and integrated coastal management. Ocean coastal management, 37(1), pp.41-62 Date received: 8/9/2018 Date reviewed: 25/9/2018 Reviewer: Assoc Dr Tran Danh Suu Date approved for publication: 25/10/2018 SCREENING OF SALT TOLERANCE POTENTIAL OF A PANEL OF VIETNAMESE RICE LANDRACES AT SEEDLING STAGE Nguyen Hoang i Giang*1, Floran Gathignol2, Le Trong Duc1, anh Tuan3, Gantet Pascal 4,5, Pham Xuan Hoi1, Lebrun Michel4,6 Abstract In the present study, thirty three Vietnamese rice landraces at seedling stage were evaluated for their salt tolerance at ve salinity levels of mM, 100 mM, 150 mM, 200 mM, and 250 mM NaCl Plants were grown in hydroponics with salt application at the fourth leaf stage Salt tolerance score, survival rate and dry weights of shoot and root were measured at and 14 days of stress e results showed that increasing salinity level from to 250 mM caused an obvious decrease in seedling growth of all tested Vietnamese rice landraces At days of stress, most genotypes exhibited a salt tolerance ranging from tolerant to moderately tolerant with increasing salinity A er 14 days, salt stress caused deleterious e ect on almost all genotypes, especially at 200 and 250 mM, where no salt tolerant genotype were observed At 100 mM NaCl treatment for 14 days, the lines Pokkali, G138 were noted to be the most tolerant and twenty other genotypes were ranked as moderately tolerant At 150 mM, G138 and G45 were evaluated to be moderately tolerant as Pokkali, whereas the others were more susceptible, but less than IR29 Keywords: Salinity, salt tolerance, landrace, growth INTRODUCTION Rice (Oryza sativa L.) is one of the most important crops as it is a staple for over billion people in the world, especially in the Asia-Paci c region With the continuous increase of the population, global food production has to double by 2050 to meet Agricultural Genetics Institute, National Key Laboratory for Plant Cell Biotechnology, LMI RICE-2, Hanoi, Vietnam IRD, Université de Montpellier, LMI RICE-2, Hanoi, Vietnam VNUA, Faculty of Agronomy, Department of Genetics and Plant Breeding University of Science and Technology of Hanoi, LMI RICE-2, Hanoi, Vietnam Université de Montpellier, IRD, UMR DIADE, 34095 Montpellier, France Université de Montpellier, IRD, UMR LSTM, 34095 Montpellier, France * Corresponding author: Hoang i Giang Email: nuocngamos@yahoo.com 27 Vietnam Academy of Agricultural Sciences (VAAS) the demand (Tilman et al., 2011) For rice, yield is increasing at 1.0% per year which is less than 2.4% per year rate needed to achieve the goal by 2050 (Ray et al., 2013) As the h biggest rice producer in the world (FAO, 2017), Vietnam has been coping with salinity intrusion in the coastal areas of Mekong delta caused by the climate change to maintain its rice production level Actually, Vietnam is one of the ve countries most a ected by climate change (IPCC, 2007) Sea level is expected to rise between 49 to 95 cm at the end of the 21st century causing salinization of both Mekong delta and Red River delta, major rice cultivated areas In parallel, the increase of temperatures up to 3.70C will make salinization of inland soils get worse (Schmidt- omé et al., 2015) e precise e ect of salinity in rice is determined by a complex interaction of several factors including the severity, timing and duration of the stress (Zeng et al., 2001) Rice salt sensitivity changes during the lifetime but most severe e ects are observed during seedlings and reproductive stage At seedling stage, salts accumulated in older leaves may cause premature senescence and slow growth of new produced leaves ( itisaksakul et al., 2015) Salt concentrations above the tolerable threshold would compromise the adaptive processes and lead to the death of the plant Vietnam is one of the centers of diversi cation of cultivated rice in Asia anks to a multitude of environmental conditions in terms of climate, landscapes and irrigation practices, many rice genotypes can be found is valuable genetic resource can be the basis of rice improvement in order to produce new high salt-tolerant varieties with high yield by breeding program e aim of this study is to identify among a panel of 33 Vietnamese rice landraces which ones show the best salt tolerance under a range of NaCl concentration MATERIALS AND METHODS Plant materials Among a panel of 182 Vietnamese rice landraces screened under a moderate salt stress (100 mM NaCl) in a previous study, 33 genotypes showing best results in term of salt tolerance were used as materials for this study (Table 1) e criteria used to select these genotypes are salt tolerance score, leaf water content, Na+ and K+ ion content and Na+/K+ ratio in leaves is panel came from diverse locations throughout Vietnam e characteristics of the full panel can be found in Phung et al (2014) Additionally, IR29 (salt-sensitive) and Pokkali (salt-tolerant) were used as standards Table List of 33 Vietnamese rice landraces used in phenotyping experiment ID Name Province Ecosyst ID Name G10 G105 G106 G107 Tam Son Nam Dinh Nep Lan Nep Hai Hau Nep Binh Lun Nam Dinh Ha Giang Ninh Binh Ninh Binh UP UP IR IR G20 G22 G24 G39 Te Le Hoa Binh Trung Trang Tuyen Quang Tam Xoan Hai Hau Nep Cam Hoa Binh na Nam Dinh Ha Giang UP UP UP RL G108 G113 G130 G133 G134 G138 G14 G154 G155 Tam Ap Be Nang iet Lua Da Bo A 330 Padai Caloc Nang Quat Tam Nho Bac Ninh Nep om Khau Pe Lanh Nep Van Ruong Hoa Binh Giong 90 Ngay Nep Quyt Hai Duong On Ninh Binh Vung Tau Khanh Hoa Khanh Hoa Khanh Hoa Ben Tre Bac Ninh Ha Tay Son La IR IR UP IR UP RL na IR UP G45 G46 G48 G50 G64 G68 G8 G83 G84 Nep Cuc Nep Ba Lao Lua Ngoi Lua Nep Ba ang Dang Ven Do Nep ang Chon Tu 502 Hoc Vien Nep Vang Ba Cho Kte Ninh Binh Nam Dinh Nam Dinh Quang Nam Quang Tri Binh Dinh na Quang Ngai Binh Dinh RL MG MG UP IR IR UP UP UP Hoa Binh na G85 Chanh Chui Kien Giang Hai Duong na RL UP na G98 Ngoi Tia G99 Lua Cham Bien G16 G165 G18 G19 Notes: na - no data available; UP - upland; RL - rainfed lowland; MG - mangrove 28 Province Ecosyst anh Hoa MG Nam Dinh Ninh Binh RL RL Journal of Vietnam Agricultural Science and Technology - No.1(3)/2018 Phenotyping experiment RESULTS AND DISCUSSION e genotypes were grown in hydroponics following the IRRI standard protocol (Gregorio et al., 1997) with di erent concentrations of NaCl (0 mM (control), 100 mM, 150 mM, 200 mM and 250 mM) and three replicates In each replicate, the genotypes were randomly distributed in one styrofoam oat of 35 holes (2 mm diameter) in an individual plastic tray (36 ˟ 31 ˟ 15 cm) lled with Peters solution (20/20/20 NPK, pH 5.1) Evaluation of salt tolerance by survival rate and salt tolerance score e experiment was set under net house conditions Seeds were germinated on water during days at 280C, then seedlings were cultured in the styrofoam oats with nylon net bottom Each genotype was grown in one hole (plot) with four seedlings Water level and pH were adjusted daily e nutrient solution was renewed once every week untill the end of experiment Salt stress was applied when seedlings reached the fourth leave stage Salt NaCl was supplemented to the hydroponic medium gradually, each time 50 mM NaCl, separated by two days to get the higher nal concentration of 250 mM NaCl e EC (electrical conductivity) value of all experimental trays was maintained by adding water or salt daily e experiment was stopped at 14 days a er the initial salt treatment Plants were monitored carefully each day a er the start of salt treatment to visualize any salt stress symptoms and side e ects A er days and 14 days, the survival rate was determined by counting the number of dead/alive plants in each plot At and 14 days of stress, salt tolerance score was assessed based on leaf injury symptoms using the modi ed standard evaluation system (salt tolerance) for rice (Gregorio et al., 1997), as follows: score (highly tolerant) normal growth, no leaf symptoms; score (tolerant) near normal growth, but leaf tips or few leaves whitish and rolled; score (moderate tolerant) - growth severely retarded, most leaves rolled, only a few are elongating; score (susceptible) - complete cessation of growth, most leaves dry, some plants dying; score (highly susceptible) - almost all plants dead or dying A er two weeks of salt stress treatment, collect aerial part and root system separately for each plot, then oven-dry the samples at 700C for days and weigh to obtain the dry weight of root and shoot Time and place of the study e experiment was conducted in the Agriculture Genetics Institute (AGI) - Hanoi, Vietnam, in August - September 2017 To assess the response of genotypes to di erent salinity levels, we recorded capacity for survival over time: a er and 14 days of salt stress treatment e results presented in Figure 1A showed that a er days of stress most genotypes reached on average the survival rate of 100% at 100 mM NaCl, with the exception of G14 and G50 for which values of 91.8% According to the assessment of salt tolerance score, genotypes were classi ed into three groups: highly tolerant (G19, G108, G138 and Pokkali), tolerant (17 genotypes), and moderately tolerant (14 genotypes, including IR29) (Figure 1B) With increasing salinity survival rate and salt tolerance of some genotypes tended to decrease a er days of stress e decrease of survival rate was observed in genotypes at 150 mM, ones at 200 mM and ones at 250 mM (Figure 1A) e salt tolerance score of genotypes ranged from to 5.67 at 100 mM, from 1.0 to 6.33 at 150 mM, from 1.0 to 7.0 at 200 mM, and 3.67 to 7.0 at 250 mM Among 35 genotypes, G19 and Pokkali exhibited the highest degrees of salt tolerance in all four tested salinity levels, whereas IR29 was the most susceptible to salinity, exhibiting the highest salt tolerance score in each treatment (i.e score at 200 mM and 250 mM) (Figure 1B) By analyzing the salt tolerance scores, a large range of number of genotypes among tolerance levels was observed, with highly tolerant group varying from genotypes at 100 mM to genotypes at 250 mM, tolerant group declining from 17 to 3, moderately tolerant group rising from 14 to 29 genotypes (Figure 1B) IR29 was always most sensitive to salt stress A er 14 days of salt stress, deleterious e ect of salt stress was clearly observed in all rice landraces and standards Both parameters of salt tolerance signi cantly declined with rising the level of salinity (Figure 2) Salt sensitive standard IR29 died in all tested levels of salinity with the salt tolerance score of 9.0 e survival rate among rice landraces ranged from 50% to 100% at 100 mM, from 0% to 91.7% at 150 mM, from 0% to 66.7% at 200 mM, and from 0% to 50% at 250 mM Genotypes were also grouped according to their tolerance level At 100 mM stress, G138 and Pokkali remained tolerant, 20 other genotypes were determined to be moderately tolerant (i.e G10, G106, G107, G108, G130, G154, G165, G19, G20, G39, G45, G46, G48, G64, G68, G8, G84, G85, G98, G99) At 150 mM, we found only 29 Vietnam Academy of Agricultural Sciences (VAAS) two moderately tolerant genotypes (G45 and G138) which were equally tolerant as Pokkali At 200 mM and 250 mM NaCl, visual damage was serious, leaf drying and seedling dead were observed on all plots, including Pokkali Interestingly, G138 was ranked at the top as Pokkali for its salt tolerance in all tested salinity levels Figure Survival rate (A) and salt tolerance score (B) of rice genotypes at days in di erent levels of salinity Figure Survival rate (A) and salt tolerance score (B) of rice genotypes at 14 days in di erent levels of salinity 30 Journal of Vietnam Agricultural Science and Technology - No.1(3)/2018 Growth characteristics A er 14 days, salt stress caused a decrease in seedling shoot and root growth in most of the genotypes (Figure 3), except for G84, which dry weights of shoot and root were larger than control condition mM, perhaps due to the experimental error e reduction was more at higher salinity levels, and almost equivalent at 200 mM and 250 mM A dramatic decrease in shoot dry weight and root dry weight (above 50% under all stress treatments compared with no salinity) was observed for G10, G14, G18, G50, G98 and IR29 Among genotypes the lowest drop in shoot dry weight (13.4 - 25.9%) and root dry weight (0 - 20.3%) was recorded for G48, indicating its tolerance to salinity Likewise, the decline of salt tolerant Pokkali was18 - 48.2% in shoot dry weight and - 38.0% in root dry weight e genotype G138 assessed for best salt tolerance among rice landraces, exhibited a decrease 0.1 - 55.7% and 15.9 - 47.7% in shoot and root dry weight, respectively Similar results were reported by Tatar et al (2010), who observed a signi cant reduction in the total dry matter of rice cultivars at the seedling stage Generally, the seedling biomass growth appeared not strongly correlated with salt tolerance among genotypes However, these morphological parameters demonstrated the ability to maintain growth of genotypes under salt stress e signi cant reduction in shoot dry weight, root dry weight as well as other growth parameters such as root length, plant height, root number per plant are considered as indicators of rice plant response to salt stress (Jamil et al., 2006; Chunthaburee et al., 2016; Hussain et al., 2017) Figure Shoot dry weight (A) and root dry weight (B) of rice genotypes at 14 days in di erent salinity levels CONCLUSIONS Large di erences between rice genotypes in response to salt stress were observed e salt tolerance and seedling growth of genotypes decreased with increasing salinity levels Signi cant reduction was observed for most genotypes at 14 days of stress in all tested salinity levels, in particular, deleterious effect was reported at the higher salinity levels e Vietnamese rice landraces were ranked with G138 as the most tolerant, equivalent Pokkali in terms of salt tolerance and seedling growth Moderately tolerant level was noted for twenty other landraces at 100 mM, and for G45 at 150 mM is study revealed that the Vietnamese rice diversity has the potential to be used for increasing salt tolerance and improve adaptation to salt stress 31 Vietnam Academy of Agricultural Sciences (VAAS) REFERENCES Chunthaburee S., Dongsansuk A., Sanitchon J., Pattanagul W., eerakulpisut P., 2016 Physiological and biochemical parameters for evaluation and clustering of rice cultivars di ering in salt tolerance at seedling stage Saudi Journal of Biological Sciences (2016), 23, 467-477 FAO, 2017 Crop prospects and food situation report Food and Agriculture Organisation of the United Nations, Gregorio G.B., Gharmawansa S and Mendoza R.D., 1997 Screening rice for salinity tolerance IRRI discussion paper Series N0.22 International Rice Research Institute Manilla, Philippines pp.2-23 Hussain S., Zhang J., Zhong C., Zhu L., Cao X., Yu S., Allen B.J., Hu J., Jin Q., 2017 E ects of salt stress on rice growth, development characteristics, and the regulating ways: A review Journal of Integrative Agriculture, 16 (11): 2357-2374 IPCC, 2007 Fourth assessment report (AR4): climate change 2007 Contribution of working groups I, II and III to the fourth assessment report of the intergovernmental panel on climate change (IPCC), Cambridge University Press, Cambridge Jamil M., Bae L.D., Yong J.K., Ashraf M.,Chun L.S., Shik R.E., 2006 E ect of salt (NaCl) stress on germination and early seedling growth of four vegetables species Journal of Central European Agriculture, 7: 273-282 Phung T.P.N., C.D Mai, P Mournet, J Frouin, G Droc, N.K Ta, S Jouannic, L.T Le, V.N Do, P Gantet and B Courtois, 2014 Characterization of a panel of Vietnamese rice varieties using DArT and SNP markers for association mapping purposes BMC Plant Biology, 14: 371 Ray D.K., Mueller N.D., West P.C., Foley J.A., 2013 Yield trends are insu cient to double global crop production by 2050 PLoS ONE 8, e66428 Schmidt- omé P., Nguyen H., Pham L., Jarva,J., Nuottmäki K., 2015 Climate change adaptation measures in Vietnam SpringerBriefs in Earth Sciences Tatar O., Brueck H., Gevrek M.N., Asch F., 2010 Physiological responses of two Turkish rice (Oryza sativa L.) varieties to salinity Turk J Agric For., 34: 451-459 itisaksakul M., Tananuwong K., Shoemaker C.F., Chun A., Tanadul O.U.M., Labavitch J.M., Beckles D.M., 2015 E ects of timing and severity of salinity stress on rice (Oryza sativa L.) yield, grain composition, and starch functionality Journal of Agricultural and Food Chemistry, 63 (8) Tilman D., Balzer C., Hill J., Befort B.L., 2011 Global food demand and the sustainable intensi cation of agriculture Proc Natl Acad Sci USA 108: 20260-20264 Zeng L., Shannon M.C., Lesch S.M., 2001 Timing of salinity stress a ects rice growth and yield components Agric Water Manage., 48: 191-206 Date received: 21/9/2018 Date reviewed: 28/9/2018 Reviewer: Assoc Dr Dang Minh Tam Date approved for publication: 25/10/2018 OVEREXPRESSION OF GMCHS7 IN SOYBEAN LEADS TO REDUCED PIGMENTATION IN HILUM OF TRANSGENIC SEEDS Nguyen Anh Vu*1, Pham Xuan Hoi1, Do i Nhu Quynh1, Nguyen Trung Anh1, Nguyen Huu Kien1, Le Huy Ham1, Nguyen Van Dong1 Abstract GmCHS7 gen was cloned and transferred to DT22 soybean plants by agrobacterial vector Transgenic plants were selected based on their resistance to ammonium glufosinate conferred by the bar gene which is co-expressed in the T-DNA e presence of transgene in surviving plants were further rmed by using PCR Transgenic plants showed no morphological di erence from DT22 variety except for hilum color which ranges from white to brown in the seeds of transgenic plants compared to black or imperfect black in that of DT22 plants e results showed that overexpression of GmCHS7 gene lead to a decreased in pigmentation of the hilum in the seeds of soybean plants Keywords: Anthocyanin deposition, GmCHS7, hilum, overexpression, reduction, soybean, transgenic INTRODUCTION Soybean [Glycine max (L.) Merr.], native to East Asia, is the most widely grown grain legume in the world Its seeds are widely used as the major sources * of vegetable oils and plant protein (Hartman et al., 2011) e plant grows annually with erected, bushy stem, reaching the height of 50 - 120 cm when fully mature Soybean seeds contain eight essential amino Agricultural Genetics Institute Corresponding author: Nguyen Anh Vu Email: nguyen.anh.vu.agi@gmail.com 32 ... among a panel of 33 Vietnamese rice landraces which ones show the best salt tolerance under a range of NaCl concentration MATERIALS AND METHODS Plant materials Among a panel of 182 Vietnamese rice. .. Figure Survival rate (A) and salt tolerance score (B) of rice genotypes at days in di erent levels of salinity Figure Survival rate (A) and salt tolerance score (B) of rice genotypes at 14 days in... other landraces at 100 mM, and for G45 at 150 mM is study revealed that the Vietnamese rice diversity has the potential to be used for increasing salt tolerance and improve adaptation to salt stress