Upload
sridhar-gutam
View
2.567
Download
17
Embed Size (px)
DESCRIPTION
Citation preview
Evaluation of Salinity Stress Evaluation of Salinity Stress Tolerance in Mango (Tolerance in Mango (Mangifera Mangifera
indicaindica L.) Genetic Resources – L.) Genetic Resources – Way Way forwardforward
H RavishankarH Ravishankar, VK Singh and Sridhar Gutam, VK Singh and Sridhar Gutam
Central Institute for Subtropical HorticultureCentral Institute for Subtropical HorticultureRehmankhera, Kakori Post, Lucknow 227107,UPRehmankhera, Kakori Post, Lucknow 227107,UP
EmailEmail: : [email protected]@gmail.com
2nd National Seminar on Management of Salt affected Soils and Waters: Challenges of the 21st Century.
CSSRI, RS, Lucknow. March 16-17, 2012
Mango – King of the Mango – King of the FruitsFruits
Area: 2.31 Mha (NHB,
2012)
Prod.: 15.02 M MT High Demand Low Supply Export: -18% (APEDA,
2012)
CISH
Wikipedia
CISH Vision 2030 - Towards CISH Vision 2030 - Towards Mitigation of Abiotic StressMitigation of Abiotic Stress
ConstraintsConstraintsGlobal climatic changes among other paradigms also envisage augmented salinization of agriculturally suited landmass.
Central Institute for Subtropical Horticulture (CISH), Lucknow, in its Vision 2030 document under the Strategy and Framework has prominently flagged the need for development and standardization of rootstocks as one of the major resilient strategies for addressing the abiotic stress constraints in mango.
Soil Salinity & Mango in Soil Salinity & Mango in IndiaIndia
Salinity and Alkalinity affected soils: 8.4 Mha (Singh et al., 2012).
Great possibility exists to bring some of these problem areas under mango cultivation.
Mango (Mangifera indica L.), the king of fruits is highly sensitive to soil salinity and alkalinity.
Therefore, its expansion in such affected areas for profitable cultivation becomes greatly restricted.
FAO
Adverse Effects & Adverse Effects & Management Management
StrategiesStrategiesAdverse effects of salinity on plant
growth could ensue due to the ion
cytotoxicity (Na+, Cl- and SO4-) and
osmotic stress.
Strategies to confer salt tolerance in
general include :
Ion exclusion, ion sequestration, osmotic
adjustments, macromolecule protection
and membrane transport system
adaptation to saline environments.
Mechanisms of Salinity ToleranceMechanisms of Salinity Tolerance
Plants have adapted a variety of mechanisms of salt tolerance
The mechanisms include:
Salt exclusion
Salt excretion
Osmotic adjustment
Membrane compositionGrosso and Bickel, 1999
Moisture stress
Decreased leaf water potential/tissue water status
Loss of turgor
Reduced metabolic activities of cells
Reduced growth and productivity
Cellular Level Tolerance Cellular Level Tolerance Maintenance of cellular metabolic activities under low tissue water status becomes a very crucial aspect.
This can be achieved by cellular level tolerance (CLT) mechanisms
Mechanisms of Salinity Mechanisms of Salinity ToleranceTolerance
Genes related to Oxidative stress management Superoxide dismutase, Glutathione transferase
like enzymes play role in reducing ROS damage.Genes related to Osmotic adjustments
Osmoprotection – desiccation tolerance -Cod A – rate limiting enzyme in production of Glycine Betaine
Genes related to Osmolytes - Proline, Trehalose Genes related to Cellular level tolerance
Aquaporins, Plasma membrane intrinsic proteins (PMIPs) regulate water movement and water balance.
Co-expression of regulatory genes (DREB, ZIP, MYC), with house keeping genes (DNA helicase involved in DNA unwinding).
Heat shock proteins (HSPs) Late embryogenesis abundant (LEA) protein and Binding proteins (BIPs) are chaperones involved in protein folding and turn over.
Mango RootstocksMango RootstocksInternational and National International and National
scenarioscenario• Mangifera indica L. cv. 13-1 of Israel is
commercially adopted as a rootstock where
calcareous soils and saline irrigation water
pose serious problems in mango cultivation in
Israel.
• This rootstock introduced to India sometimes
back is yet to be adequately tested and
exploited for different scion varieties.
Currently large scale trials are being planned
in Gujarat.• In Spain however, association of salt tolerance features of
Gomera-1 (Mangifera indica L.) is related to its capacity to
restrict the uptake and transport of Cl- and Na+ ions from the
rootstock to the above ground parts.
• Further in the study, Cl- ions were found more toxic in rootstock
and cultivar leaves while Na+ ions were more toxic in roots.
• (Zuazo, 2004)
Wikipedia
Evaluation of Polyembryonic Evaluation of Polyembryonic Rootstocks Variability for Salinity Rootstocks Variability for Salinity
ToleranceTolerance - CISH - CISH
Membrane stability varied among the polyembryonic accessions (Bappakai, Goa, IC202224, IC470676, Komanga, Kulambe, Kurukkan, Moovandan, Mylepaliun, Nekkare, Nattumanga, Olour, Pullian, Ratnagiri, Thrissur and Vellai Columban) and it is in the range of 58% - 86% when studied under open conditions.
Bappakai could tolerate salinity levels up to 5.3 dSm-1
However, further studies on these accessions exposed to salt stress needed.
M. zeylanica Hooker f. recorded a higher
K/Na ratio in all plant parts especially in
the roots implying that it manifested
greater salinity tolerance than M. indica
L. cv. 13-1
continued…..
Another feature of salt
tolerance is to maintain
higher degree of
membrane stability under
salt stress situationsWikipedia
Schmutz, 1999
Physiological DescriptorsPhysiological Descriptors
CO2 assimilation, Root respiration and Carbon gain-found as useful tools in discriminating salt tolerance between M. indica L. cv. 13-1 and M. zeylanica Hooker f.
In that M. zeylanica Hooker f. recorded higher rates of CO2 assimilation, root respiration, relatively low Na+ and Cl- contents but had higher K+, Ca++ as well as Mg++ in the leaves. Schmutz, 1999
ChallengesChallenges
• Narrow genetic base of polyembryonic mangoes- need for widening of genetic base
• Polyembryony is inherited as a recessive trait under the control of single dominant gene
• Lack of diverse rootstocks with tolerance to salinity
• Limited genomic resources for identification of genetic potentials of tolerance mechanisms
• G x E interactions and rootstock-scion compatibility
• Identification of genotypes with specific traits for salt tolerance- Transcriptome profiling, QTL mapping and MAS to tag genes
• Development of standard reliable protocols for screening against salt tolerance
Wild Mangoes – Sources of Salt Wild Mangoes – Sources of Salt Tolerance ?Tolerance ?
M. odorata
WikipediaWikipediaWikipedia
M. foetida
Way forwardWay forward : : Wild Wild Mangoes?Mangoes?
• Some of the wild mangoes (allied species of Mangifera)
dominating the South China Sea viz., M. laurina, M.
odorata, M. pajang and M. foetida that await genetical
characterization may serve as useful gene donors in
this regard
• Mangifera spp. / ecotypes endemic to the Andaman and
Nicobar islands may also provide useful insights – co
evolution with saline environments; coastal ecosystems
• Pyramiding and stacking multiple genes controlling
different aspects of salt tolerance in mango needs focus