title: Alteration of wheat vernalization requirement by alien chromosome-mediated transposition of MITE.
abstract: Under the changing climate, early flowering is advantageous to escape terminal heat and drought. Previously during evaluation of 14 chromosome introgression lines (ILs), we found three ILs that flowered a month earlier than their wheat background Chinese Spring (CS). This paper describes the cause of the early flowering in the ILs and provides insight into the evolution of spring wheat from the winter wheat. We used specific molecular markers for Vrn genes to determine its allelic composition. Phenotypic evaluations carried out under field conditions and in a growth chamber. Unlike the winter vrn-A1 allele of CS, the spring Vrn-A1 allele of the ILs had insertions of 222 and 131-bp miniature inverted-repeat transposable element (MITE) in the promoter region. Sequence analysis indicated that the 222-bp insertion is similar to an insertion in the spring genotype, Triple Dirk D. Our results ruled out any possibility of outcrossing or contamination. Without vernalization, Vrn-A1 is highly expressed in the ILs compared to CS. We attribute the early flowering of the ILs to the insertion of the MITE in the promoter of Vrn-A1. The alien chromosome might mediate this insertion.
authors.affiliation: Arid Land Research Center, Tottori University, 1390 Hamasaka, Tottori 680-0001, Japan; Agricultural Research Corporation, Wad Medani, PO Box 126, Sudan.
authors.forename: Yasir Serag Alnor
authors.initials: YS
authors.lastname: Gorafi
authors.affiliation: Arid Land Research Center, Tottori University , 1390 Hamasaka, Tottori 680-0001 , Japan.
authors.forename: Amin Elsadig
authors.initials: AE
authors.lastname: Eltayeb
authors.affiliation: Arid Land Research Center, Tottori University , 1390 Hamasaka, Tottori 680-0001 , Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Tsujimoto
keywords: alien chromosome; drought; introgression line; transposon; vernalization; wheat evolution