Bread wheat sustains genes for grain softness on “Ha” locus of short arm of 5D chromosome. Pina-D1 and Pinb-D1 alleles of “Ha” locus together are responsible for soft grain texture… Click to show full abstract
Bread wheat sustains genes for grain softness on “Ha” locus of short arm of 5D chromosome. Pina-D1 and Pinb-D1 alleles of “Ha” locus together are responsible for soft grain texture of wheat. The wheat cultivar WL711 had wild type Pinb-D1a and mutated Pina allele, imparting hard kernel texture. A 5U-5A substitution line of Aegilops triuncialis had extra soft grains. Efforts were made to transfer puroindolines from Aegilops triuncialis 5U as 5U-5A substitution line BTC17 to its homeologous chromosome 5A of bread wheat. A total of 367 5U-5A substitution recombinants developed through induced homeologous pairing by ph1b deletion of Ph1 locus were screened for the presence of Pina and Pinb. Only 23 lines were found to have both Pina and Pinb. Grain hardness index of recombinants with functional puroindolines was reduced from 6 to 67%. Deletion mapping of wheat 5A chromosome specific SSR markers revealed the maintenance of synteny in 5U and 5A homeologous chromosomes and puroindolines were found to be translocated at the telomeric end of 5A short arm. Translocation of puroindolines from 5U was confirmed by sequencing of Pina and Pinb genes. The Pina nucleotide sequence was found 100% similar to Aegilops markgrafii (CC). Puroindoline proteins extracted from the selected softer lines exhibited significant antimicrobial activity against gram positive and gram negative bacteria. Chromosome 5U puroindolines transferred to 5A may be pyramided with 5D of soft wheat to develop extra soft varieties for superior biscuit making quality.
               
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