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1、水稻耐盐机理研究的重要进展（Important progress of study on salt tolerance mechanism in Rice）Important progress of study on salt tolerance mechanism in RiceSalt tolerant quantitative trait gene SKC1Gao Jiping, Lin Hongxuan *(Institute of plant physiology and ecology, Shanghai Institute of life sciences, Chinese Ac
2、ademy of Sciences, Shanghai 200032)Received date: 2005-10-20Project supported by the Ministry of science and Technology (2002AA2Z1003), the National Natural Science Foundation of China (30170571), the Shanghai science and Technology Commission (03DJ14016), Shanghai and Hong KongMolecular biological
3、sciences research foundation.Authors brief introduction: Gao Jiping (1968 -), male, doctoral candidate, assistant researcher, Lin Hongxuan (1960 -), male, doctor, research fellow, author of correspondence.Article number: 1004-0374 (2005) 06-0563-03Soil salinization limits crop growth and causes crop
4、 lossesOne of the most serious abiotic stresses. According to statistics, the worlds saltAlkali land area of over one billion hectares, of which, Chinas saline land surfaceThe plot reached one hundred million hectares. In our existing arable land, at leastEight million hectares of land, due to impro
5、per irrigation and fertilization, led toThe accumulation of salt in soil affects the yield of crops to some extent.Improving the resistance of crops by genetic improvement is the solution to this problemOne of the most effective ways of thinking. Therefore, it is necessary to recognize from the gene
6、tic point of viewKnowing the mechanism of salt tolerance in nature, this will help to pass through moleculesBreeding methods can improve the ability of crops to resist salt stressThe development of the industry is of great significance.Rice is one of the most important crops in the world, and it is
7、also our countryThe most important food crop. The study of functional genomics in rice is internationalThe areas of great concern are very competitive. In recent years in our countryIncrease the support in this regard, through the unremitting efforts of scientists,China has made great achievements i
8、n the study of rice functional genomicsFruit 12. Recently, our country has studied the important functional genes in RiceA breakthrough has been made between us and the American University of California, BerkeleyIn cooperation with Professor Sheng Luan, the number of salt tolerance related to rice w
9、as cloned successfullyQuantitative trait gene SKC1, and elucidate the biological function of this geneAnd mechanism of action 3. This mechanism of understanding salt tolerance and breeding in cropsImprovement is of great significance.1 quantitative trait loci (QTL) related to salt toleranceCrop stre
10、ss resistance and many important agronomic traits, such as yieldThe quantity, growth period and so on, are controlled by many genesThe phenotype showed a continuous distribution, with no phenotype between genotypesSuch a trait is called a quantitative trait. controlThe position of a gene in a genome
11、 in quantitative characters is called a quantitative trait baseQTL (quantitative, trait, locus).Genetic linkage using molecular markers covering the entire genomeAnalysis could determine the number of QTL that controls quantitative traits on chromosomesPosition and calculate the effects of each QTL.
12、 After furtherFine positioning allows the decomposition of such QTL into a single Mendel causeThe daughter is cloned in a monogenic manner. Genetic basis of quantitative traitsIt is complex and easily influenced by environmental factors, so it is quantitativeThe shape of the QTL is very small.The sa
13、lt tolerance of plants is also a quantitative trait controlled by many genesUsing QTL location strategy to analyze complex salt tolerance characters can be revealedThe natural variation of salt tolerant genes is important to study the mechanisms of salt tolerance in plantsNew approach. Applied molec
14、ular marker linkage analysis has been reported in severalPreliminary localization of salt tolerance QTL in rice populations was carried out in 48, howeverThe effects of these QTL were relatively small and no major QTL was found.In recent years, we have been tolerant of highly tolerant indica rice va
15、rieties N, O, N, and aBokra (Oryza, sativa, L., ssp., Indica, var., Nona, Bokra) and saltSensitive japonica rice cultivars were more light (Oryza, sativa, L., ssp.)Japonica, VaR, Koshihikari) hybridization,F2 groups were used to construct the scoreThe tag linkage map is combined with 140mM NaCl to p
16、rocess the corresponding F311 of the seedlings of the seedlings were related to salt stress toleranceQTL:3 were related to seedling survival days by QTL and 8 with K+,Na+ concentration was related to QTL. Among them, SKC1 is one under Salt StressQTL (Shoot, K+, Content) maintained above ground potas
17、sium concentration,Located on chromosome 1 in rice. The contribution rate of SKC1 to phenotypic variation is up toTo 40.1%, it is a master effect QTL9. These results are for cloningThe salt tolerant QTL in Nona Bokra lays the foundation.2 potassium and sodium ion transport and plant salt tolerancePo
18、tassium is the most abundant nutrient in plantsThe concentration of elements in cells is very high, up to 100150 mM 10.K + in plant cell elongation, leaf movement, tropism, movement, and maintenanceThe dynamic balance of metabolism, germination, osmoregulation, stomatal movement, andTolerance to sal
19、t stress plays an important role in 1112. In cellIn substance, the activity of many enzymes can be activated by K+ and inhibited by Na+ by 13.Salt stress caused by high concentrations of Na+ in the soil includes osmosisStress, ion toxicity and ion imbalance or nutritional deficiency, 14. Salt stress
20、Stress causes a variety of physiological and biochemical changes in plants, such as photosynthesisLow energy consumption, increased nutrient intake, and the increase of reactive oxygen speciesAccumulation of metabolic toxins and so on. These changes lead to the growth of plantsThe plant was eventual
21、ly killed because of carbon starvation.The tolerance of plants to salt mainly depends on the toxicity of Na+The adaptive capacity, as well as the nutritional status of K + itself. salt stressDamage to plants is mainly caused by the entry of Na+ into cellsAs a result of poisoning, high levels of Na+
22、in soil destroy K+ and othersThe absorption of metal elements causes osmotic stress and oxidative stress 15. stayUnder normal physiological conditions, N, a +, as a trace element, is absorbed by plantsCollect. During salt stress, a large amount of N a + enters the plant from the rootWithin, the Na +
23、 concentration was increased; whereas the uptake of K + was inhibited by K +Concentration decrease. In order to ensure normal physiological activities, plants need to be adjustedBody height and cell levels maintain high K+ and low Na+ status as much as possible.Therefore, the salt tolerance of plant
24、s and the balance of K+ and Na+ in vivo can be maintainedThe force is closely related with salt resistant than K + / A + high N ratio of plantsStrong 16.Salt tolerance of rice was also confirmed: relative to salt sensitive riceThe content of K + in leaves of salt tolerant rice varieties was higher t
25、han that of salt tolerant varietiesHigh and low Na+ content, higher K+/Na+ ratio, 17. becauseThis clone SKC1, which controls the potassium concentration under Salt StressEffects of Q, T and L are important for understanding the salt tolerance mechanism of rice.Cloning and functional studies of 3 SKC
26、1We used the method of map based cloning, which was refined by BC2F2 populationLocation, BC3F2 population, high-precision linkage analysis, the final SKC1 will be fixedKB was located between two molecular markers separated by 7.4 3. At this 7.4 KBOnly one gene exists as a candidate gene for SKC1.We
27、genetically modified the candidate gene for complementation experimentsNona Bokras SKC1 gene shifts to another salt sensitive riceVariety zhonghua11, also at 140 mM under NaCl stressThe potassium concentration in the leaves, leaves and other tissues of transgenic riceMaintained at a high level, and
28、the upper part of the sodium ion concentration was significantTransgenic controls less than null plasmids. These results were correlated with genetic analysesConsistent, it proved that we successfully cloned QTL SKC13. This isTo date, the first cloned salt tolerant related QTL in plants.SKC1 encodes
29、 a HKT family of ion transporters(554 amino acids) that exclusively transport Na+ without participating in K+,Transport of Li+ and other cations 3. HKT family transportersSub carrier transport activity varies,Such as wheat, TaHKT1 is potassium / sodium the sameThe transporter 1819, and Arabidopsis A
30、tHKT1, is the same as SKC1Sodium ion transport protein 20. SKC1 is thin and thin around the xylemIn the cells, the expression level in roots increased significantly under Salt StressThe expression of shoots did not change, 3.NSKC1 (Nona, Bokra, SKC1 protein) and KSKC1 (the more)There are 4 amino aci
31、ds that displace between the SKC1 proteins of lightNatural variation is the molecular basis for the functional differences of S, K and C 1.Both NSKC1 and KSKC1 have sodium transport activity, but NSKC1The transport activity is about 30% higher than that of KSKC1. In order to salt varieties, the more
32、 lightAs a genetic background of the near isogenic line NIL (SKC1), NSKC1Instead of the light itself KSKC1. NIL (SKC1) and more light phaseCompared with salt stress, NIL (SKC1) maintained high K+/ and low Na+ detachmentThe balance of the seedlings and the survival time of the seedlings were signific
33、antly prolonged, and the salt tolerance of the seedlings was prolongedRaise 3.The contents of K+ and Na+ in xylem sap and phloem sap were measuredK+ and Na+ were found in phloem of NIL (SKC1) under Salt StressThere was no difference between the content and the light, but the concentration of K + in
34、xylem increased significantlyPlus, the concentration of Na+ decreased obviously, 3. From this, it is speculated that SKC1The mechanism of action is that a large amount of Na+ passes through wood when rice is subjected to salt stressThe sap flows from the root to the upper part of the ground, causing
35、 large amounts of Na+ to accumulate in the groundThe upper part, while the SKC1 actively sends the Na+ out of the xylem, passes through the othersThe transport of sodium transporters causes Na+ to return from the phloem to the rootsAnd excreted, so that the upper part of the Na+ content decreased an
36、d alleviatedSodium ions are toxic, while K+ and Na+ transport are competitive in plantsWith 21, Na+ inhibited K+ uptake, when xylem Na+ concentration decreasedAt low levels, transport of K+ increased, resulting in a decrease in K+ concentration due to salt stressPartial recovery. Therefore, SKC1 reg
37、ulates rice aboveground under Salt StressThe potassium / sodium balance of the fraction, i.e., maintains the state of high potassium and low sodiumAnd increase salt tolerance of rice.Although the same is the HKT family of sodium ion transporters, Dan ZiyeAction mechanism of SKC1 in plant rice and Ar
38、abidopsis thalianaThe mechanism of action of AtHKT1 is entirely different. AtHKT1 is mainly in phloemThe ministry expresses that when subjected to salt stress, AtHKT1 will shoot the upper part of the Na+Enter the phloem sieve tube and return Na+ from the upper part to the rootThe concentration of Na
39、+ in leaves, shoots and stems was lower than 20.4 significance of the studyThe salt tolerance of plants is a combination of multiple physiological processesSodium ions are present in all two levels of tissue and cellsThe absorption and discharge of ions; the balance between ions (especially potassiu
40、m / sodium ion levels)The redistribution of ions, etc. Search for potassium, sodium, and plasma transportSixth issue, Gao Jiping, et al. The important progress of salt tolerance mechanism in pot rice - Studies on salt tolerance quantitative gene S, K, C 1 565To understand their role in salt stress,
41、protein transport is the salt tolerance of plantsIn the field of sexual studies, an important research field.The absorption, translocation and distribution of K+ in plants are mainly through potassium ionChannel and transporter proteins complete. In plants, potassium channels includeTwo families: th
42、e Shaker family and the KCO family; potassium ion transportProteins can also be divided into two families: the KUP/HAK/KT family and the HKTFamily. They are numerous in number and functional in Arabidopsis29 genes were found to control the transport of K+ in various tissues, respectively, 22.Ion cha
43、nnels and transport eggs that are involved in plant Na+ uptake and transportWhite included: non selective cation channel 23, monovalent cation channel 24,Na+/H+ reverse transporter family and HKT family, etc.These studies have revealed each of the potassium and sodium ion transport systems in plants
44、The function and mechanism of a protein, but not the function of a single proteinEffect size of total potassium and sodium ion content change. We appliedQTL positioning and high generation backcross methods were used to control multiple traits with complex traitsQTL were broken down into individual
45、Mendel genetic factors (genes) to be studiedFor the first time, it was proved that the concentration of potassium in the upper part of rice was controlled by salt stressThe major factor is the sodium transporter 3, a HKT family.Rice is known to have the largest number of members of the HKT familyGen
46、ome sequencing has been completed for Japonica Rice Cultivars in the genome of JapanA total of seven HKT transporters, 25, were found. Model plantArabidopsis thaliana has only one HKT family translocation protein AtHKT1He has no more than two plants. So rice is the study of HKT ionsHow does the tran
47、sport system evolve and function in complex eukaryotes?Ideal model.The cloning and functional research of SKC1 are important functional bases of rice in ChinaBecause of the outstanding achievements of the study, not only has important academic significanceIt has a certain application prospect. SKC1 is a salt tolerant riceGenetic and breeding studies provide favorable genes through molecular marker assis