STRESS When some factors of the environment interfere with the expression of genotypic potential • ABIOTIC • BIOTIC Stresses are abiotic or biotic ABIOTIC STRESSES Environmental, nonbiological •Temperature (high / low) •Water (high / low) •Salt •Radiation •Chemical BIOTIC STRESSES Caused by living organisms •Fungi •Bacteria •Viruses •Insects •Herbivores •Other plants/competition Stresses induce metabolic developmental responses and Injuries occuring in susceptible plants, can lead to impeding flowering, death Preferable! Productivity losses due to stress Loss due to diseases range from 20 to 30 %, in case of severe infection, total crop may be lost Estimated global loss due to insect pests in potential yields of all crops is ~14%. In India losses due to insect pests ranges from 10 to 20 % Abiotic stresses reduce average yield of crops by upto 50% (Bray EA 1997) In India also 67% of the area is rain-fed and crops in these areas invariably experience droughts of different magnitudes Annually about 42% of the crop productivity is lost owing to various abiotic stress factors ( Oerke et.al., 1994). Stress resistant crops are a dire need • Human population continues to increase: Nine billion expected by 2050. • Global warming and climate perturbations are likely to accentuate biotic as well as abiotic stresses Climate Change analysis in Punjab Since 1970 Average minimum temperature has increased by about 1oC Relative humidity increased at : Ludhiana, Ballowal Saunkhri, Jalandhar Bathinda Sunshine hours have decreased at : Ludhiana, Ballowal Saunkhri, Jalandhar Pan Evaporation has decreased at : Ludhiana, Ballowal Saunkhri, Bathinda Anticipated abiotic stress induced crisis in Indo-Gangetic plains • Conventional rice cultivation may become unsustainable in the Indo-Gangetic plains due to ground water exploitation greatly in excess of recharge. Recharging of aquifers to be hit further by less rain and snow and shrinking of himalayan snow cover • Temperature effects predicted to be more pronounced in this region. Wheat with already strained adaptation in the region is likely to be hit hard. For every 1 C increase in mean temperature above normal, grain yield is reduced by 12-23 per cent. Climate change induced pest problems in the region • Increasing incidence of several species of cereal aphid in wheat, barley and oats • Attack of mealy bug (Phenococcus solenopsis), white fly (Bemisia tabaci) and Spodoptera litura on cotton • Leaf folder (Cnaphalocrocis medinalis) and plant hoppers (Nilaparvata lugens and Sogatella furcifera) have emerged as major pests of rice • Shoot fly (Atherigona spp.) and pyrilla are emerging as important pests of maize and sorghum crops Contd. Climate change induced pest problems in the region • Stemfly (Ophiomyia phaseoli) and blister beetle Mylabris spp. have emerged as major pests of pulse crops • Cabbage caterpillar (Piersis brassicae), tobacco caterpillar (Spodoptera litura), American bollworm (Helicoverpa armigera), several species of aphids, whitefly, leafminer, spider mites and blister beetle are causing increasing damage in different vegetable crops • Fruit piercing moth (Eudocoma spp.), mealy bugs and fruit flies are causing increasing damage to fruit crops Emerging disease problems CROP Wheat Rice DISEASE Powdery mildew, foliar blight and black tip of grain Sheath blight, neck blast, false smut, foot rot, brown leaf spot, kernel bunt, grain discoloration Cotton Cotton leaf curl, foliar leaf spot Maize Bacterial stalk rot Sugarcane Oilseeds Red stripe Sclerotinia stem rot Potato Scab scurf, fusarial dry rot Tomato Early blight Cucurbits Cucumber mosaic Chillies Leaf curl Citrus Fruit drop, gummosis, sooty mold Papaya Papaya leaf curl Increasing disease problems Soil health problems Shift in status of insect pests Thermal stress Less water/ flooding Climate changes By 2025, India will need to produce: •125 million tonnes (mt) of rice (current: ~104 mt) •115 mt of wheat (current: ~93 mt) Responding to challenges posed by biotic and abiotic stresses through crop improvement • Every new objective added to a breeding programme almost doubles the magnitude of work • Unlike past successes (e.g., dwarf varieties), future increases in productivity potential are not likely to be accompanied by enhanced inputs • Genetic improvements need to be accomplished under demanding time frames Can routine breeding programmes meet these challenges ? Elements of an enhanced breeding strategy • Wide hybridization • Marker assisted selection • Transgenics Integration with conventional breeding for biotic and abiotic stress tolerance Illustrating the integrated approach: some initiatives at PAU • Heat tolerance in wheat using wide hybridization and molecular markers • Wide hybridization for disease resistance in wheat • Marker assisted selection for rust resistance in wheat • Marker assisted selection for bacterial blight in rice • Water use efficiency in rice using transgenic and molecular marker strategies • Molecular markers for drought and flooding tolerance in maize • Rootstock transformation for salinity tolerance in citrus • Cloning genes for disease resistance • DH facilitated accelerated breeding for resistance to biotic and abiotic stresses Developing a complete panel of T. durum-Ae. speltoides chromosome segment substitution lines as a source of heat tolerance in wheat Strategy used for developing T. durum – Ae. speltoides introgression lines Triticum durum Ae. speltoides X (PDW233/PDW 274) X (pau3809) T. durum F1 BC1F1 X T. durum BC2F1 selfing BC2F6 T. durum – Ae. speltoides introgression lines 800 introgression lines developed 384 taken up for molecular marker analysis and phenotyping 100 randomly selected ILs phenotyped and genotyped for developing introgression profiles and association analysis as a pilot study Molecular marker profile of 90 introgression lines from Triticum durum x Aegilops speltoides Ae. speltoides chromosome segments associated with heat stress tolerance Trait linked markers Chromosome LOD Score PVE(%) Plant yield Xcfa2278 2B 3.3225 10.9 Chlorophyll content Xgwm148 2B 2.7567 14.7 Chlorophyll content Xgwm566 3B 2.7386 12.9 Xcfd60 5B 3.1114 16.1 TTC cell viability Wide hybridization for disease resistance in wheat • More than a 1000 accessions of wild and related species germplasm maintained as active collection • More than 20 disease resistance genes being introgressed from alien species T. monococcum, T. boeoticum, Ae. tauschii, Ae. ovata, Ae. triuncialis, Ae. umbellulata, Ae. caudata and Ae. variabilis to cultivated wheats • PAU has the distinction of designating the first three alien rust resistance genes from India: Yr40 (yellow rust), Lr57 (brown rust) and Lr58 (brown rust) using molecular marker technology Transfer and mapping of leaf rust and stripe rust resistance genes from Aegilops geniculata and Ae. triuncialis in wheat. Alien genes introgressed into cultivated wheat varieties from wild Aegilops and Triticum species Donor Trait Gene(s) Ae. geniculata Leaf rust, Stripe rust Lr5-Yr40 (5DS) Ae. triuncialis Lr58 (2BL), LrT, PmT, CreT (5U) Ae. umbellulata Leaf rust Powdery mildew, CCN, Karnal bunt Leaf rust, Stripe rust Ae. caudata Leaf rust, Stripe rust LrC (5DS) Ae. variabilis Leaf rust Stripe rust Leaf rust Stripe rust CCN Powdery mildew Leaf rust Karnal bunt Powdery mildew Leaf rust Stripe rust LrV (2AL) YrV LrTm (6A); QYrtm.pau-2A(2A) QYrtb.pau-5A(5A); Qcretm.pau1A (1A) Qcretm.pau-2A (2A); PmTb7A.1 & PmTb7A.2(7A) LrAt (2D) KbAt (1D, 2D, 6D) PmTa LrTa YrTa T. monococcum & T. boeoticum) Ae. tauschii T. araraticum LrU-YrU (5DS) WORKING WITH MARKER TAGGED RUST RESISTANCE GENES IN THE WHEAT BREEDING PROGRAMME Sr2, Sr 22, Sr26,Sr 39, Year Crosses (F1s) with a Yr 5, known gene parent Yr 10, Yr 15, 2007-08 3 out of 592 Yr 24, Yr 36 Yr C591, 2011-12 455 out of 764 Yr40/Lr57 Lr19/Sr25 Lr24/Sr25 Lr 28, Lr28, Lr 24/Sr24 Lr34/Yr18, Lr 58, Yr/Lr Ae. Umb Yr/Lr T.m.-T.b. 2007-08 2011-12 PBW343 + Lr24 + Lr28 Avocet 6*/Yr10 X PBW343 + Lr24 + r28 Avocet 6*/Yr15 X MAS MAS BC2F1 BC2F1 MAS MAS Yr10 positive Yr15 positive X Crossed seed F1- complex Sowing at Off season location (Keylong-2009) Yr PYRAMIDING OF FOUR GENES : Lr 24, Lr 28, Yr 10 and Yr 15 IN PBW 343 Six hundred and fifty one (651) single plants sown at Ludhiana (2009-10) : MAS MAS 2850 F4 COMP PROGENIES (2010-11) Positive plants advanced to offseason location (Keylong 2010) MAS Bulking of selected single plant progenies (Keylong 2011) MAS Yield trials: 688 entries (2011-12) Seed multiplication at Keylong Recreating mega varieties: Marker assisted background selection (MABS) MABS • • • • Phenotypic selection PBW621*3/(AVOCET+Yr5 ) PBW621*2/(PBW 568+Yr36) PBW343*2//PBW621/(AVOCET+Yr5) PBW343*2//PBW621/(PBW 568+Yr36) High throughput genotyping system sanctioned under FIST project (DST) Initiative of PAU & WSU • Varietal background recovered in just 2 backcrosses • Minimum linkage drag • Limited testing needed in the field Molecular marker interventions in wheat: Towards commercialization in North Western Plains Zone Entry PBW 697 PBW 698 PBW 702 PBW 703 PBW 722 PBW 723 Stage (2013-14) Conditions AVT 1st yr AVT 1st yr Timely sown, Irrigated AVT 1st yr AVT 1st yr AVT 1st yr Special trial for MAS products Late sown, Irrigated Timely sown, Irrigated Genetic background + genes % yield increase over check DBW 18+ Lr57/Yr40 9.30 PBW 343 +Lr24+Lr28+Yr10 +Yr15 7.94 PBW 533+Yr15 13.94 PBW 343 +Lr24+Lr28+Yr10 +Yr15 7.09 PBW 343 +Lr37/Yr17+Lr57/Yr40 PBW 343 +Lr57/Yr40 +Yr15 -- -- Wide hybridization for bacterial blight and brown plant hopper resistance in rice • Four bacterial blight resistance genes Xa38, xa-g(t), xab(t) and Xa-r(t) has been transferred to cultivated rice background from Oryza nivara, O. glaberrima, O. barthii and O. rufipogon, respectively • Candidate genes for Xa38 has been identified and work for cloning this gene is in progress • Genes for brown plant hopper has also been identified in wild rice germplasm and are being mobilized to cultivated rice. Identification, transfer and mapping of BB resistance gene Xa38 from Oryza nivara Development of improved Basmati386 through MAS by pyramiding of bacterial blight resistance genes xa13 and Xa21, semi dwarfing gene sd1 and monitoring the retention of genes conferring aroma, amylose content and grain elongation genes and release of Punjab Basmati 3. Improving water use efficiency in rice Genetic engineering approach Molecular marker based interventions Genetic transformation of rice variety PR 121 using gly I and gly II genes through particle bombardment Genetic transformation of PR 121 Genes used Calli bombarded Calli selected on hygromycin (30 mg/l) Calli transferred to regeneration medium No. of putative transgenic plantlets regenerated gly I and gly II 1440 432 (30.0%) 415 251 (17.43%) Genetic transformation of PR 122 Genes used gly I and gly II Calli bombarded 195 Calli transferred to regeneration medium Calli selected on hygromycin (30 mg/l) No. of putative transgenic plantlets regenerated 117 118 (60.51%) 65 (33.33%) Genetic transformation of PR 118 Gene used Calli bombarded Calli selected on hygromycin (30 mg/l) No. of calli regenerated No. of putative transgenic plantlets regenerated Plants analyzed for PCR No. of PCR-positive plants gly I 2600 322 (13.39%) 91 249 (9.57%) 155 13 (0.5%) 558 bp PCR-positive samples of PR 118 (T0) [L= Ladder, PC = Positive control, NT = Non-transgenic control] PCR-positive plants of PR 118 (gly I gene) Preliminary evaluation of transgenic lines for salt stress tolerance Material screened for salinity tolerance at 0, 8 and 12 dS/m salinity levels under transgenic glasshouse: T2 generation of 1 line of PR118 (DREB1A gene) T1 generation of 2 lines of PR 118 (gly I gene) 0 dS/m 8 dS/m 12 dS/m Generation of three RIL populations for investigating adaptation to aerobic conditions S. No. Cross Generation Population size 1 PAU3116/CT 6510-24-1-2* F10 228 2 PR120/UPLRi7** F10 193 F9 379 3 PR115/CRR 615-PR-27699-D808-4-4*** *CT 6510-24-1-2 & **UPLRi7- are upland rice and ***CRR615-PR- drought tolerant line from CRRI, Cuttack Traits studied: • Iron deficiency induced chlorosis (IDIS) • Plant Height • Days to 50% flowering • Number of tillers • Number of grains /panicle • Spikelet fertility • Plot yield Twenty high yielding entries from each RIL population were taken up for testing as part of the breeding programme for aerobic rice A B Variation of chlorosis (IDIC) in RILs at early growth stage under aerobic conditions. (A)- Chlorotic (B)- Non chlorotic Molecular profile of PAU3116 x CT6510-24-2-1 RIL population using SSR markers Recombinant inbred lines P1 P2 C RM566 P1 P2 C Recombinant inbred lines RM302 P1 P2 C Recombinant inbred lines RM212 Molecular data is being generated on PAU 3116/Ct651024-2-1 population for tagging QTL’s related to yield components under aerobic conditions Markers associated with important traits under water logging stress in maize TRAIT ASSOCIATED MARKERS CHROMOSOME NUMBER Plant Height umc1701 1 Plant mortality umc1701 umc1117 umc1029 phi027 1 4 7 9 Leaf senescence umc1636 9 Leaf rolling bnlg1496 phi076 umc1577 3 4 7 Total no. of ears/line umc1701 1 No. of grains/line umc1035 3 Grain weight bnlg1601 umc1035 3 3 Anthesis silking interval umc1053 10 I 110 (S) x I 172 (T) mapping population Chromosome 1 umc1685 (0.0) Chromosome 3 Chromosome 4 phi104127 (0.0) umc1117 (0.0) umc1577 (0.0) umc1793 (27.8) bnlg1189 (26.1) umc2061 (0.0) umc1808 (35.2) umc1701 (22.9) bnlg1144 (62.3) umc2002 (0.0) Leaf senescence Leaf rolling Total no. of ears/line No. of grains/line Grain weight ASI SPAD1 (C) SPAD2 (C) umc1015 (61.5) umc1667 (31.1) SPAD 1 SPAD 2 Plant Height Plant mortality Chromosome 7 umc1399 (35.9) bnlg1601 (57.7) umc1539 (75.3) umc1035 (108.3) umc2000 (140.6) umc2152 (169.8) phi034 (85.5) umc2291 (60.7) umc1339 (119.2) umc2325 (0.0) phi076 (92.0) Both stress and non stress umc1029 (34.3) phi328175 (54.0) bnlg1070 (83.8) Plant height (C) No. of grains/line (C) Grain weight (C) ASI (C) bnlg1496 (199.4) umc1409 (111.4) Chromosome 8 bnlg1194 (0.0) phi119 (25.5) Chromosome 9 umc1583 (0.0) bnlg1401 (23.5) phi027 (0.0) phi115 (0.0) umc1636 (28.1) Chromosome 10 bnlg2190 (0.0) umc1962 (29.5) umc1318 (54.6) bnlg2046 (32.5) SPAD 1 SPAD 2 umc1470 (64.5) Plant Height Plant mortality umc1471 (93.9) Leaf senescence Leaf rolling Total no. of ears/line No. of grains/line Grain weight ASI SPAD1 (C) SPAD2 (C) Plant height (C) No. of grains/line (C) Grain weight (C) ASI (C) umc 2371-1 (61.0) umc1084 (85.2) umc2338 (81.5) bnlg1012 (108.4) umc1053 (0.0) umc2067 (16.9) umc1657 (126.7) umc 2371-3 (149.3) umc 2371-4 (179.1) umc 2371-2 (0.0) umc1366 (15.1) umc1077 (47.9) GENETIC TRANSFORMATION OF CITRUS ROOT STOCK FOR TOLERANCE TO SALINITY Epicotyls bombarded with gly 1 Proliferation of shoot buds Subculture on MS + BAP (0.5 mg/L) Doubled haploidy as a breeding tool • Cuts short the breeding cycle by 3-4 years • Freezes every recombination event for evaluation, selection and use in further crosses • Genetic advance higher than any other method • Strengthens the ‘breeding option’ in face of sudden biotic and abiotic challenges ACCELERATED BREEDING: WHEAT OFFSEASON OPERATIONS AT KEYLONG Doubled haploid facilitated accelerated breeding initiated in major crops • Wheat: wheat x maize crosses-3000 lines/year • Maize: haploid inducer lines from CIMMYT • Rice: anther/microspore culture Is our knowledge of molecular-genetic basis of plant resistance to stress adequate to allow us to step beyond natural variation and design transgenics that combine stress tolerance and high productivity? Abiotic and biotic stress tolerance: a basic unity Cascade is strikingly similar signal perception, signal transduction, activation of transcription factors, activation of cis-acting response elements and finally a well coordinated expression of a large set of genes Abiotic and biotic stress tolerance: a basic unity • The difference: Biotic stress tolerance in most cases based on a strong central switch (the R gene) while a network of switches (transcription factors) governs reponse to abiotic stresses A unifying pattern across species • Molecular and genetic studies show Arabidopsis and rice share common mechanisms regulating response to abiotic stress • Transcription factors (TFs) which play an important role in regulating gene expression are common between grasses and Arabidopsis The current reach of transgenic manipulations • Transcription factors (TFs) such as DREB1/CBF, DREB2, AREB/ABF, NAC are powerful targets for genetic engineering of stress tolerance • Constitutive expression of TFs is, however, counter productive-stunting, dwarfing, developmental abnormalities • Effective inducible expression systems (including promoters) need to be established • Cloning of new genes for resistance to biotic and abiotic stresses remains as a major need Cloning of antifungal genes from local antagonistics and generation of gene cassettes for genetic transformation GENE NAME GENE SOURCE ANTAGONISTIC TARGET CROP TRAIT Glucanase & Chitinase Trichoderma viride Phytophthora parasitica Roughlemon Foot rot root stock Glucanase & Chitinase Trichoderma viride Phytophthora parasitica Sugarcane (CoJ 83) Red rot Glucanase Trichoderma viride Phytophthora parasitica Cotton (RG8) Fusarium wilt Glucanase Trichoderma viride Rhizoctonia solani Rice (Kitaake) Sheath blight Future Outlook • Scientists are able to visualize in individual experiments hundreds of genes involved in the complex phenomenon of plant response to stress • Made possible by advent of new powerful technologies: » High throughput or next generation DNA sequencing » Genome wide gene expression profiling » Advances in bioinformatics Strengthening precision screening high throughput phenotyping: Phenomics THANKS
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