Slide 1: 1 1 1 Welcome
seminar series
2011-12
Slide 2: GENETIC ANALYSIS FOR SALT TOLERANCE IN RICE (Oryza sativa L.) Major Guide:-
Dr. P.B. Patel,
Assistant research scientist,
CSSRS-Danti,NAU,Navsari. SPEAKER : YASHLOK SINGH Co- Guide:-
Dr.M.K.Mahatma,
Asst. professor
Dept.of Biotechnology 2
Slide 3: Introduction
Salt tolerance mechanism
Breeding for salt tolerance
Saltol QTL
Review of research work
Conclusion Content 3
Slide 4: 4
Slide 5: 5 Rice (Oryza sativa L., 2n= 24) is originated from Southeast Asia. Rice is short day, C3 plant and hydrophilic in nature. Rice is the staple food of more than 50% of word population including Asia, Latin America and South Africa etc. Rice rank second to wheat in terms of area harvested but in the terms of importance as a food crop rice provide more calories per hectare than any other cereals. Asia cultivates 137 m ha of rice of which India’s share is 45 m ha (Anon., 2010). The salinity and sodicity are the important factors adversely affecting the soil health and crop production. The total salt affected area in India approximately 8.1 m ha, out of which 3.2 m ha in coastal saline (Anon., 2009). Of course, this is dynamic problem. Total salt affected area in Gujarat is 1.2 lakh ha. In South Gujarat alone around 70,000 ha area (59% of total salt affected area of Gujarat) is salt affected, which cover coastal parts of Bharuch, Surat, Navsari and Valsad districts. In coastal areas of south and middle Gujarat, paddy is a major crop during kharif season. In coastal salt affected soil, the gap between achievable and existing productivity in paddy indicates that there is a good scope to raise the production and productivity through crop improvement. INTRODUCTION
Slide 6: EXTENT OF SALT-AFFECTED SOILS Asia, Pacific and Australia (M ha) 195 249 Source : FAO database (2009) Total : 444 M ha 6
Slide 7: What are the salt-affected soils ? Saline soils: Soluble salts – Cl- & SO4-2 of Na+ - salinity could vary in season
Sodic Soils: CO3-2 & HCO3- of Na+ and Na+ on colloidal surface of clay micelle 7
Extent and distribution of salt - affected soil in India. (‘000 ha.) : Extent and distribution of salt - affected soil in India. (‘000 ha.) Source –CSSRI, Karnal (2009) 8
Slide 9: Distribution of salt affected soils in Gujarat state (ha) Source –Khar Land Development Authourity ,Gujarat ( 2008) 9
Different rice breeding /testing centres for sodicity and salinity stresses in India. : Different rice breeding /testing centres for sodicity and salinity stresses in India. CSSRI,Karnal Gautam et al.(2008) 10
Slide 11: Collaborating Countries / Institute in Asia Iran Pakistan CRRI, India BRRI, Bangladesh BINA CSSRI, NDUAT India Vietnam KAU, TNAU, India Indonesia Philippines Myanmar Thailand Sri Lanka 11
Slide 12: Selectivity of ions
Intracellular compartmentation
Osmoregulation
Organic solutes
Inorganic solutes
Antioxidants and ROS- scavenging
LEA-type protein synthesis 12
Slide 13: Salt Resistance Primary Stress Avoidance Tolerance Salt Exclusion Salt Extrusion Salt Dilution Avoidance of ion
balance strain Tolerance of ion balance strain Low salt permeability Salt extrusion pump Water absorption Mineral binding with organic substances Mechanism of Salt resistance under primary stress condition 13
Slide 14: Secondary stress Osmotic stress Nutrient stress Avoidance (Osmotic adjustment) Tolerance Deficiency Toxicity Accumulation of
organic solutes in
cytoplasm and salts
in vacuoles Increase in wall extensibility Increase in leaf thickness Avoidance Tolerance Selectivity of ion uptake Replacement of K by Na Avoidance Tolerance Salt glands and bladders Control of transport to shoot Succulence Mechanism of Salt resistance under secondary stress condition Ion compartmentation 14
Slide 15: Sucrose
Trehalose
Sorbitol
Inositol
Mannitol
Glycerol
Arabinitol
Pinitol
Other polyols Proline
Betaine
Glutamate
Aspartate
Glycine
Choline
Polyamines Oxalate
Malate Carbohydrate
and polyols Nitrogenous compound Organic acid Important osmolytes that accumulates in plants during salinity 15
Slide 16: 16
Slide 17: Generation and scavenging of superoxide radical and hydrogen peroxide, and hydroxyl radical-induced lipid peroxidation and glutathione peroxidase-mediated lipid (fatty acid) stabilization 17
Slide 18: SOS signaling pathway for ion homeostasis under salt stress in rice. 18
Slide 19: Traditional (conventional ) approach
Somaclonal Variation
Anther Culture
Mutation Breeding
Marker assisted selection(MAS)
Transgenic approach 19 Method of breeding for salinity tolerance
Slide 20: Modified standard evaluation score (SES) of visual salt injury at seedling stage in rice. Source –IRRI, Philippines(2009) 20
Slide 21: Reasons of Limited Success 21 Salt stress seldom happen in isolation
Highly variable environment, large G/E
Lack of efficient / precise screening procedure
Lack of mechanism understanding
Low priority and less number of researchers involved
Slide 22: Salt Stresses and Associated Complexities 22
Slide 23: Mostly quantitative trait Breeding
for Grain Yield Salt-Tolerance 23
Slide 24: 1. Restricting the entry of toxic ions at root level - Exclusion 2. Transporting the toxic ions to stem, leaf sheath or older leaves – plant level compartmentation 4. Sequestration of the toxic ions to vacuole or cell wall – cell level compartmentation 3. Excretion of salt through salt glands, salt-hairs or bladders – in most halophytes Predominant salt-tolerance mechanisms operating in plant Na+ Cl- 24
Slide 25: Physiology: traits associated with salinity tolerance
Slide 26: Morphological Symptoms
v White leaf tip followed by tip burning (salinity)
Leaf browning & death (sodicity)
Stunted plant growth
Low tillering
Spikelet sterility
Low harvest index
Less florets per panicle
Less 1000 grain weight
Low grain yield
Change in flowering duration
Leaf rolling
White leaf blotches
Poor root growth
Patchy growth in field Manifestation of Salt Stress 26
Slide 27: First symptom
“Leaf tip burning” “Leaf tip burning extends toward base through Lamina” “Ultimate death of leaf – always from oldest to youngest” Salinity symptoms at the vegetative stage 27
Slide 28: Effect of salinity at Reproductive stage – Spikelet Sterility 28
Slide 29: Effect of salinity at reproductive stage – papery sterile spikelets 29
Slide 30: SALINITY Genetics of Salt Tolerance
Inheritance Pattern 30
Slide 31: Genetics of Salt Tolerance P1 X P2 F1 X F1 X P1 31
Slide 32: Performance of FL478 (tolerant line) and IR29 (susceptible variety) rice seedlings under saline solution . (Source: IRRI (2010) 32
Slide 33: Physiological & Biochemical
v High Na+ transport to shoot
v Preferential accumulation of Na in older leaves
v High Cl- uptake
v Lower K+ uptake
v Lower fresh and dry weight of shoot and roots
v Low P and Zn uptake
v Increase of toxic organic compatible solutes
v Increase in Polyamine levels Causes of Salt Stress in rice 33
Slide 34: Breeding Strategy Identification of the genotypes based on the inherent physiological mechanism responsible for salinity tolerance
Inter-mating of the genotypes with high degree of expression of the contrasting salinity tolerance mechanism
Identifying / screening of the recombinants for pooling/ pyramiding of the mechanisms 34
Slide 35: Identify the donors for predominant physiological mechanisms responsible for salt tolerance
Na+ exclusion,
Tissue Tolerance
K+ uptake,
Preferential accumulation of Na+ in stem, leaf sheath, older leaves etc.
Early vigour
However, none of the rice variety posses all the possible positive mechanism conferring salinity tolerance. Breeding Strategy 35
Grouping of the rice varieties on the basis of Na accumulation per day : Grouping of the rice varieties on the basis of Na accumulation per day
Slide 37: Grouping of the rice varieties on the basis of K accumulation per day 37
Slide 38: Rice variety A
Good excluder
+
poor tissue tolerance
Rice variety B
Poor control at root level
+
High tissue tolerance Dustbin Garbage
Na+ Rice variety C
Good excluder
+
High tissue tolerance K+ 38
Slide 39: An Ideal High Yielding Salinity Tolerant Variety of Rice Highly tissue tolerant
Good Excluder- Minimum per day uptake of Na+
High uptake of K+ per day
Low Cl- uptake
Low Na+/ K+ ratio
Good initial vigour
Agronomically superior with high yield potential
(plant type + grain quality) 39
Slide 40: C52903S C1733S R2374B C52903S C1733S R2374B RM283 R844 S2139 RM23 RM140 RM113 S1715 S13994 RM9 RM5 C1456 RM237 RM246 0.0 27.4 28.4 40.0 75.3 77.2 91.9 98.2 99.1 103.1 119.5 123.5 129.9 RM283 R844 S2139 RM23 RM140 RM113 S1715 S13994 RM9 RM5 C1456 RM237 RM246 0.0 27.4 28.4 40.0 75.3 77.2 91.9 98.2 99.1 103.1 119.5 123.5 129.9 0.0 1.0 1.8 1.9 1.2 1.3 Short arm of chromosome 1 Progress of Saltol locus Saturated map of the Chromosome 1 (Saltol segment) is developed
Closely linked
markers linked to the saltol locus
identified. 60.6 40
Mapping Salinity Tolerance Genes at Reproductive Stage : Mapping Salinity Tolerance Genes at Reproductive Stage QTLs for salinity tolerance genes at seedling
stage are different from reproductive stage
Seedling stage tolerance in chrom- 1.
Reproductive stage tolerance in chrom- 3, 4, and 7. 41
Slide 42: Early Seedling Stage Boot stage Vegetative / tillering stage Rice Growth Stages vs. Salt Tolerance Germination Stage Ripening
Donors : Donors Traditional Donors
Pokkali
Cheriviruppu
Nonabokra
Bhirpala
SR26B
Hasawi Improved Donors
FL478
PSBRc 88 / CSR23
CSR28
IR4630-22-2-5-1-3
CSR10
BR47 Rice : Salt - sensitive crop
: Enormous variability 43
Slide 44: Salt tolerant rice varieties released for commercial cultivation in different countries 44
Review of Research work : Review of Research work
Slide 46: Screening 46
Slide 47: Table -1: Survival scoring of varieties under saline condition SD- Survival day, RL- Root length, SL- Shoot length, RW- root weight, SW- shoot weight,
HT- Highly tolerant, T-Tolerant, MT- Moderately tolerant, S- Susceptible, HS- Highly susceptible Vietnam Lang et al. (2001) 47
Slide 48: Table 2: Salinity score , Na+, K+ content and Na+/K+ ratio in shoot of rice
genotypes grown under salinized solution. Pakistan Ali et al. (2004) 48
Slide 49: Table 3: Grain yield and yield components under saline and normal soil
field conditions. Pakistan Ali et al. (2004) 49
Table 4: Salt tolerant rice genotypes and their salient traits. : Table 4: Salt tolerant rice genotypes and their salient traits. Karnal Gautam et al.(2008) 50
Table 5: Distribution of 11 genotypes under salt stress at seedling stage : Table 5: Distribution of 11 genotypes under salt stress at seedling stage Bangladesh Bhowmik et al. (2009) 51
Slide 52: Table 6 - Chlorophyll a, Chlorophyll b and total Chlorophyll, Proline content and Na/K ratio of seedling in two rice genotype KKU,Thailand Pajuabmon et al. (2009) 52
Slide 53: Gene Action 53
Slide 54: Table 7: Estimation of general combining ability (GCA) effects for various characters of rice in a diallel cross Pakistan Mahmood et al.(2002) 54 Significant at 5 % level
Slide 55: Table 8: Estimation of SCA effect for various character of rice varieties in a diallel cross Pakistan Mahmood et al.(2002) 55
Slide 56: Bangladesh Saharay and Islam (2008) Table 9: Genetic parameter and x2 values of joint scaling test in an additive dominance model for salinity tolerance scores in six crosses of rice 56 ** Significant @ 1 %
Table 10 : Gene effects for salinity tolerance scores under six parameter model in rice : Table 10 : Gene effects for salinity tolerance scores under six parameter model in rice Bangladesh Saharay and islam (2008) 57 ** Significant @ 1 % & * significant @ 5 %
Table 11- Promising hybrids for grain yield per plant (g) with heterobeltiosis, relative heterosis and component traits based on pooled over environment in rice (L X T) : Table 11- Promising hybrids for grain yield per plant (g) with heterobeltiosis, relative heterosis and component traits based on pooled over environment in rice (L X T) PL= Panicle length GPP= Grains per panicle PTP=Productive tillers per plant
TW = 1000- Grains weight HI= Harvest index PC= Protein content NAU, Navsari Sharma (2008) 58 ** Significant @ 1 %
Table 12: Performance of different varieties under normal and saline conditions {16 (dS m-1)} : Table 12: Performance of different varieties under normal and saline conditions {16 (dS m-1)} NAU, Navsari Patel et al. (2010) 59
Slide 60: Molecular Approaches 60
Slide 61: Khan Kaen , Thailand Kanlaya et al.(2005) Figure1 : The SDS-PAGE profiles of polypeptides extracted from controlled (C) and salt-treated (S) roots (A), leaf sheaths (B), leaf laminae (C) of rice cv. Leuang Anan 61
QTLs for salinity tolerance : QTLs for salinity tolerance 1 2 3 4 5 6 7 8 9 10 11 IRRI Bonilla et al.(2002) 62 Figure-2
Slide 63: Saltol 1 2 3 4 5 6 7 8 9 10 11 12 Sub1 Evaluation of salinity + submergence tolerant plants by submerging in saline water IRRI Bonilla et al.(2002) 63 Figure-3:
Slide 64: 64 The rice productivity under salt affected soil can be increased through selection of tolerant variety.
Screening for salinity should be major areas for large scale testing of salt tolerance.
Breeding approaches will help to enhance the genetic and physiological basis of resistance against salinity.
Under Salt tolerant mechanisms, the level of tolerance can be enhanced by High tissue tolerant, Good excluder, Minimum per day uptake of Na+, High uptake of K+ per day, High K/Na ratio, Good initial vigour and Agronomically superior with high yield potential (plant type + grain quality).
Good donors (Pokkali, Nonabokra, CSR-10, KDML-105), and reliable phenotyping is the key to success.
Multiple abiotic stress tolerance is possible and should be addressed because salt stress invariably occurs with other abiotic stresses or mineral toxicity/ deficiency.
Transfer of Saltol QTL in different varieties will validate the effectiveness. Use of salt-tolerant varieties is a viable proposition to reclaim the salt-affected areas and to enhance the productivity of rice under salinity condition. Conclusion
Slide 65: Thank you … 65