Protocols for pre field screening of mutants for salt. The narrow genetic pool of japonica germplasm for salinity tolerance and the extent of the salinity challenge are. Salt stress tolerance is a complex trait, so the qtls related with salt tolerance have significant role in understanding the stress response and generating stresstolerant plants gorantla et al. Modifying sodium transport to improve salinity tolerance of. Soil salinity is one of the most devastating factors threatening cultivable land. Salinity is a major abiotic stress limiting growth and productivity of plants in many areas of the world due to increasing use of poor quality of water for irrigation and soil salinization. Salinity is a major constrain to high yield of rice oryza sativa l. This study was designed to identify useful agronomic.
The following cycles were used in the abi 7500 fast system 96 wells plates. Molecular characterization and identification of new sources of tolerance to submergence and salinity from rice landraces of coastal india volume 17 issue 3 r. Pdf salinity and salt tolerance improvements in thai rice. Rice is rated as a salt sensitive crop, especially at early seedling and reproductive stages 1, 2. Modifying sodium transport to improve salinity tolerance of commercial rice cultivars oryza sativa l. Among the various abiotic stresses limiting the crop productivity, salinity stress is a major problem, which needs to be addressed and answered urgently. Screening for salt tolerance in the field is difficult as soil salinity is dynamic. Tagging and validation of ssr markers to salinity tolerance. The next frontierthe use of genome editing for integration free. Pdf evaluation of salinity tolerance in rice genotypes. However, mr211, mr232 and ir20 performed better based on.
A panel of ethanemethylsulfonatemutagenized japonica rice lines was grown in the presence of salinity in order to identify genes required for the expression of salinity tolerance. Molecular characterization and identification of new. Salinity effects on seedling growth and yield components of rice linghe zeng and michael c. The salt tolerance of several australian and overseas rice varieties was studied at germination, early vegetative growth, and reproductive development in a temperature controlled glasshouse to determine the reliability of screening at any particular stage.
Background salinity is a major abiotic stress limiting yield in many parts of the world. Rhoades, usda ars salinity laboratory, riverside, california. Variability for salt tolerance among some rice varieties. Rice plants generally tolerate salt by mainly two mechanisms, ion exclusion and osmotic tolerance munns and tester, 2008.
Screening six varieties of rice oryzasativa for salinity. Nov 17, 2016 rice plants were grown in waterlogged conditions, to represent this aspect of irrigated rice fields that should be included in salinity tolerance studies, as the effects of hypoxia on salinity. Wild rice germplasm is considered a valuable genetic resource for improving rice cultivars. Progress in rice breeding for salt tolerance, constitutes the identification of the major locus conferring a salt tolerance gene at different growth stages. Placing all the results together we could deduce osmyb481 to be a novel mybrelated tf of rice for abiotic stress tolerance. Genetically improving salt tolerance of rice is a highly important objective of rice breeding programs. Genetic analysis of salt tolerance at seedling and reproductive stages in rice oryza sativa rezamohammadi 1,3,merlyns.
However, mr211, mr232 and ir20 performed better based on dry matter. The typical mechanism of salinity tolerance in rice is the na exclusion or uptake reduction, and increased absorption of k to maintain a good nak balance in the shoot. Frontiers improvement of salt tolerance using wild rice. Effects of salinity stress on growth, chlorophyll content and. Testing method for salinity tolerance at germination stage on. Plants differ greatly in their tolerance of salinity, as re. Mechanisms of salinity tolerance in plants have been extensively studied and in the recent years these studies focus on the function of key enzymes and plant morphological traits. As the transcription levels of osrr9 and osrr10 altered under several abiotic stresses, we first characterized their role in salinity tolerance. It is a complex quantitative trait having different components, which can be dissected effectively by genomewide association study gwas.
School of biosciences the university of birmingham august, 20. Traditional rice landraces of coastal area in bangladesh are distinct regarding their phenotype, response to salt stress and yield attributes. Effect of salinity on chlorophyll concentration, leaf area, yield and yield components of rice genotypes grown under saline environment y. Characterizing the saltol quantitative trait locus for. Rice transcription factor osmads25 modulates root growth and. Breeders have long made use of the high level of salinity tolerance in landraces like nona bokra and pokkali. Effect of salinity on chlorophyll concentration, leaf area. Since members of brassicaceae are important contributor to total oilseed production, there is an. Modifying sodium transport to improve salinity tolerance. New phenotyping technique for salinity tolerance at reproductive stage in rice.
In this study, 305 bacteria were isolated from paddy soil in taoyuan, china. Salt tolerance behaviour of cultivars based on different selection criteria was compared. The rice genotypes differed significantly for salt tolerance at seedling stage. Considerable genetic variation in salt tolerance among rice varieties exists. The objective of this study was to develop a new salttolerant rice germplasm using speedbreeding. Among these, 162 strains were tested for salt tolerance.
Four simple sequence repeats ssr markers rm493, rm10793, rm3412 and rm10791 found in the saltol locus in chromosome 1 were used for molecular analysis. Although several transporters involved in salt tolerance have been identified in rice, the mechanisms regulating their transport activity are still poorly understood. In addition to conventional breeding, other innovative breeding techniques such as tissue culture, induced mutations and wide crosses needed to be. Here, we show that transcription factor osmads25 positively regulates the root system development and tolerance to salinity and oxidative stress in rice plants. Genomewide association mapping of salinity tolerance in. Salinity effects on seedling growth and yield components of rice. Here, we provide an updated overview of salt tolerant mechanisms in glycophytes with a particular interest in rice oryza sativa plants. Markerfree transgenic rice plant overexpressing pea lecrlk. The validity of this technique was tested by conducting experiments in salinised soil pot culture and in salt affected field where 9 rice lines were grown up to maturity and absolute paddy yield was considered as the criterion for salt tolerance.
Effects of salinity stress on growth, chlorophyll content and ion accumulation in two indica rice oriza sativa l. Many qtls have been identified in rice for salinity tolerance contributing traits and majority of them have been reported on chromosome 1. Accordingly, there was a major difference in the salt tolerance of the three wheat organs, root was the most salt sensitive organ while spikes was the most salt. New phenotyping technique for salinity tolerance at. Breeding for salt tolerance is a major goal for rice breeders for which screens are required to select out tolerant lines for breeding. Despite many attempts using different strategies to improve salinity tolerance in rice, the. Salttolerant and plantgrowthpromoting bacteria isolated. Salt stress tolerance is a complex trait, so the qtls related with salt tolerance have significant role in understanding the stress response and generating stresstolerant plants gorantla et. Many qtls have been identified in rice for salinity tolerance contributing traits and majority of.
On the basis of tolerance ability toward salinity, rice is considered as salt sensitive crop, and growth and yield of rice are. Mohammad rashed hossain a thesis submitted to the university of birmingham for the degree of doctor of philosophy. Stress and disease tolerance irri rice knowledge bank. At all 3 stages, varieties differed in their degree of tolerance, but the order of tolerance varied considerably between stages.
Genomewide association study of seedling stage salinity. In addition to conventional breeding, other innovative breeding techniques such as tissue culture, induced mutations and wide crosses needed to be explored. Therefore, the aim of this experiment was to uncover prospective rice landraces tolerant to salinity. Drought and salt are two of the most serious threats to food production worldwide, and research on stress tolerance in crops is important for future food security. Evaluation of salt tolerance in rice genotypes by multiple. Study of salt tolerance in wheat triticum aestium l. One of the identified endophytic fungus, which was tolerant to high concentrations of salt, was transferred to the saltsensitive rice variety ir64. An endophyte from saltadapted pokkali rice confers salttolerance. Mutants for salt tolerance in rice, wheat and barley. Pdf salinity is considered as one of important physical factors influencing rice oryza sativa l. However, information regarding the improvement of salt tolerance in cultivated rice using wild rice genes is limited. Worldwide rice is grown on some 400 million hectares of salt affected land.
But the concentrations of na, zn, cu and mn increased. This method controls soil heterogeneity by using pure sand as a growth medium and minimizes unexpected extreme weather. A rapid screening technique for salt tolerance in rice. Testing method for salinity tolerance is performed in a greenhouse by transplanting 14 daysold seedling on soil salinized with 4000 ppm nacl. Free proline content was measured by a colorimetric assay as described by bates et al. Course material from the usda nrcs training course, management of saline and sodic soils 1991, a series of five training notes by dr. Salinity is a serious threat to rice production in southern bangladesh. Biomolecules free fulltext the tolerance of salinity in. Singh, plant breeder at the international rice research institute, discusses the latest progress in salinty tolerance research in rice. Overexpression of rice expansin7 osexpa7 confers enhanced tolerance to salt stress in rice chuluuntsetseg jadamba 1, kiyoon kang 2, namchon paek 2, soo in lee 3, and soocheul yoo 1, 1 crop molecular breeding laboratory, department of plant life and environmental science, hankyong. Rice is a major staple crop and immensely affected by soil salinity. We also provide strong evidence that osmads25 increases. Rice plants were grown in waterlogged conditions, to represent this aspect of irrigated rice fields that should be included in salinity tolerance studies, as the effects of hypoxia on salinity.
On the basis of tolerance ability toward salinity, rice is considered as saltsensitive crop, and growth and yield of rice are. Molecular characterization and identification of new sources. Pihog1, a stress regulator map kinase from the root. The concentrations of p and k in the tops of rice cultivars decreased with increasing soil salinity. The vast genetic variability reported in rice in response to salinity makes it amenable to genetic manipulation to further enhance its tolerance akbar et al. An analysis of 100 ssr markers on 140 ir29pokkali recombinant inbred lines rils confirmed the location of the saltol qtl on chromosome 1 and identified additional qtls associated with tolerance. Here, we show evidence that a rice mg transporter osmgt1 is required for salt tolerance probably by regulating transport activity of. Identified genomic regions associated with salinity tolerance accelerated molecular. The effect of salinity on dry matter production varied from cultivar to cultivar.
Singh 1,4 1plant breeding, genetics and biotechnology division, international rice research institute, dapo box 7777, metro manila, philippines. The purpose of this study was to establish the relative importance of different traits associated with salinity tolerance in rice and to identify new quantitative trait loci qtl conferring tolerance to salinity at seedling stage. Identification of new qtl for salt tolerance from rice. Therefore, the improvement of salinity tolerance in rice has come to the fore. However, some salt tolerant bacteria improve the health of plants under saline stress. Improvement of salt tolerance in rice oryza sativa l. Salinity threat is estimated to reduce global rice production by 50%. Salt stress is one of the major factors limiting rice oryza sativa production globally.
Excess salinity in soil is one of the major environmental factors that limit plant growth and yield of a wide variety of crops including rice. Electro physiologically, increasing salinity reducedthe electrical pd of plant leaves. The levels of the antioxidant enzymes cat and apx and the accumulation of proline may play important roles in salinity tolerance. Here, we characterized the rice oryza sativa really interesting new gene ring h2.
Characterizing the saltol quantitative trait locus. Salinity tolerance in rice is highly desirable to sustain production in areas rendered saline due to various reasons. Dissecting molecular mechanisms underlying salt tolerance in rice. However, rice is very sensitive to salinity and is the most salt sensitive cereal crop with a threshold of 3 dsm. Effect of salinity stress on growth and carbohydrate. Plant adaptation or tolerance to salinity stress involves complex physiological traits, metabolic pathways, and molecular or gene networks. Mapping qtls for traits related to salinity tolerance at. Response regulators 9 and 10 negatively regulate salinity. Soil salinity is one of the major constraints affecting rice production worldwide, especially in the coastal areas. Susceptibility or tolerance of rice plants to high salinity is a coordinated action of. Salinity tolerance loci revealed in rice using high.
Pearson, 1959 and attempts to enhance the salt tolerance in rice through breeding date from the early 1970s akbar et al. Under the abiotic stress, reactive oxygen species ros and free. Salt stress causes significant reductions in rice production worldwide. Rice varieties mr211, ir20, br40 and mr232 showed greater salt tolerance during germination germinated at 12 ds m 1 salinity.
Pdf improvement of salinity stress tolerance in rice. A magnesium transporter osmgt1 plays a critical role in. On the basis of tolerance ability toward salinity, rice is considered as salt sensitive crop, and growth and yield of rice are greatly affected by salinity. To this end, threeleafstage rice seedlings wild type and osrr9osrr10 mutant were exposed to 150. Forno d a, cock j h and gomes k a 1976 laboratory manual for physiological studies for rice. Exposure of wildtype rice to salinity upregulated fln2, while a crisprcas9generated fln2. Discussion the protective role of proline against naclinduced oxidative.
Salinity imposes both ionic toxicity and osmotic stress to plants hasegawa et al. Aris hairmansis a thesis submitted for the degree of doctor of philosophy school of agriculture, food and wine faculty of sciences the university of adelaide february 2014. Shannon abstract reduction were observed scardaci et al. A highly nontolerant selection proved to harbor a mutation in fln2, a gene which encodes fructokinaselike protein2. Here, we implemented gwas to identify loci controlling salinity tolerance in rice. Improvement of salinity stress tolerance in rice mdpi. Improving salt tolerance in rice therefore is essential for ensuring food. Salt tolerance improvement in rice through efficient snp marker. Salinity laboratory, usda ars riverside, ca abstract the capability of crops to grow on saline soils varies among species and depends on the concentration of salts presen t in the rootzone and on various environmental and cultural conditions. Genomic and transcriptomic analysis reveal molecular basis. Rice salinity tolerance is complex, both genetically and physiologically.
Sep 16, 2010 this study characterized pokkaliderived quantitative trait loci qtls for seedling stage salinity tolerance in preparation for use in markerassisted breeding. Molecular dissection of seedling salinity tolerance. Mar 25, 2014 to our knowledge, it is the first report that mybrelated type tf, osmyb481, involved in drought and salt tolerance in rice. These mechanisms can also be further classified into ion exclusion, osmotic tolerance and tissue tolerance roy et al. Salinity is one of the most widespread abiotic stresses affecting rice productivity worldwide.
Despite many attempts using different strategies to improve salinity tolerance in rice. Evaluating rice for salinity using potculture provides a. Identification of molecular markers tightly linked to salt tolerant genes can serve as land marks for the physical localization of such genes facilitating marker assisted selection mas. Assessing trait contribution and mapping novel qtl for. Genetic analysis of salt tolerance at seedling and. Pdf screening rice for salinity tolerance, vol 22, irri. Salt tolerance is an important constrain for rice, which is generally categorized as a typical glycophyte. Characterizing the saltol quantitative trait locus for salinity tolerance in rice. Genetic variation for salinity tolerance in pakistani rice oryza sativa l. Investigations of the effects of salinity on rice have been underway for more than 50 years kapp, 1947. Pdf characterizing the saltol quantitative trait locus. Different salinity affects differently on electrical plant leaf pd of the six varieties of rice. Significant varietal differences were found in relation to salinity tolerance. Information on the relative tolerance of different.
A new salinity tolerance screening technique using rice seedlings in potculture was tested. To understand the molecular basis of salt tolerance in cmg, we performed bsaseq for two extreme bulks derived from the cross between cmg and a cultivar sensitive to salt, zhefu802. Gregorio and others published screening rice for salinity tolerance, vol 22, irri discussion paper series find, read and cite all the research you need on researchgate. It would also be the next frontier for integrationfree. In spite of considerable effort, through both international and national breeding programmes, progress in. With characterization of these landraces, suitable candidate genes for salinity tolerance could be identified to introgress into modern rice varieties. Dca1 acts as a transcriptional coactivator of dst and. Of the cereals, rice oryza sativa is the most sensitive and barley hordeum vulgare is the most tolerant figure 1. Tahir nuclear institute for agriculture and biology, faisalabad, pakistan abstract. The study to develop a testing method for salinity tolerance at germination stage was conducted from. The threshold for salt stress in rice is 3 dsm, with a 12% reduction in yield for each unit increase in dsm beyond this value 3. The main objective of this study is to determine the effects of salinity stress on growth and carbohydrate metabolism in rice cultivars differing in salinity tolerance.
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