Vernalization requirement duration in winter wheat is controlled by TaVRN‐A1 at the protein level

Abstract

Winter wheat requires a period of low temperatures to accelerate flowering (vernalization). This requirement could make winter wheat more vulnerable to elevated global temperature via insufficient vernalization. All known vernalization genes are cloned according to qualitative variation in vernalization requirement between spring and winter wheat, but the genes controlling quantitative variation for more or less vernalization requirement among winter wheat cultivars remain unknown. We report here that the gene for the vernalization requirement duration in winter wheat was cloned using a BC1F2:3 population that segregated in a 3:1 ratio of early-flowering plants and late-flowering plants after vernalization for 3 weeks. The positional cloning of the gene for vernalization requirement duration demonstrated that this trait is controlled by TaVRN-A1 at the protein level. The Ala180 in vrn-A1a, encoded by the dominant allele for 3–week vernalization, was mutated to Val180 in vrn-A1b, encoded by the recessive allele for 6–week vernalization. Further studies with in vitro protein pull-down assays and immunoprecipitation analyses indicated that the mutated Val180 in vrn-A1b protein decreased the ability to bind with TaHOX1 (the first homeobox protein in Triticum aestivum). The direct binding of TaVRN-A1 and TaHOX1 proteins was confirmed in the nucleus of living plant cells by bimolecular fluorescence complementation (BiFC) analyses. The TaHOX1 gene was found to be upregulated by low temperatures, and to have a significant genetic effect on heading date, suggesting that TaHOX1 functions in the flowering pathway in winter wheat.

Identification of the VERNALIZATION 4 gene reveals the origin of spring growth habit in ancient wheats from South Asia

“…We characterized two common wheat varieties with reduced vernalization requirement linked to the VRN-A1 locus (6,44). Jagger (KS-82-W-418/STE-PHENS), a hard red winter wheat, was the most widely planted variety in Kansas and Oklahoma for 12 y.…”

“…The second haplotype, found in VRN-D4 and the related VRN-A1 sequences in CS, Jagger, and Claire (henceforth RIP-3 VRN-D4 ), included the previous T2783C SNP and two additional SNPs at positions 2,780 (G2780C) and 2,784 (C2784T). Interestingly, the VRN-A1 alleles from Jagger and Claire have been previously linked to a weak vernalization requirement (6,44).…”

“…The VRN-A1 allele from CS has not been characterized in detail, but the winter wheat varieties Jagger and Claire have a reduced vernalization requirement (6,44) that maps to the VRN-A1 locus. The cause of the reduced vernalization requirement is still controversial and has been attributed to copy number variation in Claire (6) and to a polymorphism (A180V) in the VRN-A1 protein in Jagger (44). The discovery that both Claire and Jagger carry the RIP-3 VRN-D4 allele provides an alternative explanation for their reduced vernalization requirement.…”

Analysis of the VERNALIZATION-A1 exon-4 polymorphism in polyploid wheat

“…В настоящее время предложено несколько ДНК-марке-ров, идентифицирующих гаплотипы экзона-4 и 7 гена VRN-A1, большинство из них основаны на методе ре-стрикционного анализа фрагментов ПЦР (Chen et al, 2009;Eagles et al, 2011;Li et al, 2013;Yan et al, 2015). В неко- торых исследованиях гаплотип экзона-4 выявляли в ходе анализа хроматограмм секвенирования соответствующих ампликонов (Zhang et al, 2015) или субклонов (Chen et al, 2013), а также с использованием KASP-генотипирования (Díaz et al, 2012).…”

“…Доминантные аллели VRN1 обусловливают яровой или факультативный тип развития (отсутствие потребности в яровизации или ее частичное сохранение соответственно), тогда как рецессивные аллели характеризуются необхо-димостью в яровизации и обусловливают озимый тип развития. В то время как альтернативные доминантные аллели генов VRN1 оказывают различное влияние на ко-личественные показатели ряда качественных признаков в яровых сортах, полиморфизм рецессивного аллеля vrn1 ассоциирован с модуляцией чувствительности к про-должительности яровизации, морозостойкости, времени выхода в трубку и колошения озимой пшеницы (Chen et al, 2009;Dhillon et al, 2010;Eagles et al, 2011;Díaz et al, 2012;Li et al, 2013;Yan et al, 2015).…”