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Physio-biochemical responses and allelic diversity for water deficit tolerance related traits in Aegilops tauschii and Triticum dicoccoides

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Title Physio-biochemical responses and allelic diversity for water deficit tolerance related traits in Aegilops tauschii and Triticum dicoccoides
 
Creator Suneja, Yadhu
 
Contributor Gupta, A.K.
 
Subject wheats, irrigation, planting, genes, enzymes, proteins, amino acids, weather hazards, tolerance, acidity
 
Description In the present study, a set of fifty seven Aegilops tauschii (DD genome), twenty six Triticum
dicoccoides (AABB genome) accessions, wild wheat progenitors, along with tetraploid durum and
hexaploid wheat cultivars was evaluated for several drought-responsive traits under irrigated and rainfed
conditions. Membrane injury in field brought leaves subjected to an in vitro 40% PEG stress ranged from 21.43% (AT-251) to 87.19% (TD-424) in wild wheats. Ae. tauschii accessions (AT) as a group, revealed high level of membrane stability, beyond that observed in cultivated wheats. T. dicoccoides (TD) showed higher levels of proline induction, like TD-346 that exhibited 9-fold induction under rain-fed conditions. Some Ae. tauschii accessions showed a unique behavior in maintaining constitutively higher levels of proline. Ae. tauschii accessions- AT-300, AT-310 and T. dicoccoides- TD-347, TD-351, TD-359 and TD-360 were found superior for plant height (indicative of accumulated biomass), peduncle (indicative of stem reserves) and spike length (a yield component) under stress. In a set of selected accessions, an Ae. tauschii accession- AT-26 showed up-regulation in the activity of all the five assayed antioxidant enzymes- superoxide dismutase, peroxidase, catalase, ascorbate peroxidase and glutathione reductase under rain-fed conditions. Activity of three of these enzymes increased in AT-51, AT-262 and AT-186 under stress. Triticum dicoccoides maintained higher enzyme activities even under irrigated conditions. Lab-based evaluation of all Aegilops tauschii, Triticum dicoccoides accessions and check wheat cultivars for seedling growth under control and PEGinduced stress identified Aegilops tauschii-AT-18, AT-264, AT-284, AT-299, AT-304 accessions and
Triticum dicoccoidies- TD-359 and TD-365 accessions to maintain optimum root-shoot length and
biomass under water deficit stress. PAGE-based allelic diversity analysis in Ae. tauschii germplasm for
drought-responsive genes uncovered four allele classes in Dreb1a, five in Dreb1b, three in Wdhn13,
four in Wrab17 gene exclusive to Ae. tauschii accessions, not present in durum and bread wheat.
Sequencing analysis was carried out in six Aegilops tauschii accessions, PBW-343 and C-306 for each
of the three genes- Dreb1, Wdhn13 and Wrab17. An amino acid variant- G35A was identified in AT-
243 in coding region of the gene Wdhn13. Nucleotide diversity (both SNPs and InDels) in the 3’UTR
of Wdhn13 distinguished Ae. tauschii accessions among themselves. Sequenced portion of the Dreb1
gene showed no nucleotide variant. For Wrab17 gene, a four base InDel was identified in the intron of
AT-09. In silico analysis found AetWDHN13 to be twelve amino acids smaller than TaWDHN13. ITASSER
predicted Ala 63, Met 64, Lys 66, Ala 67, Gly 86, Ser 87, Gly 90 to constitute binding
pocket of TaWRAB17.
 
Date 2016-04-26T11:58:46Z
2016-04-26T11:58:46Z
2014
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/65592
 
Language en
 
Format application/pdf