The TaDREB3 transgene transferred by conventional crossings to different genetic backgrounds of bread wheat improves drought tolerance.
Drought tolerance of the wheat cultivar Bobwhite was previously enhanced by transformation with a construct containing the wheat DREB3 gene driven by the stress-inducible maize Rab17 promoter. Progeny of a single T2 transgenic line were used as pollinators in crosses with four elite bread wheat cultivars from Western Australia: Bonnie Rock, IGW-2971, Magenta and Wyalkatchem, with the aim of evaluating transgene performance in different genetic backgrounds. The selected pollinator line, BW8-9-10-3, contained multiple transgene copies, had significantly improved drought tolerance compared with wild-type plants and showed no growth and development penalties or abnormalities. A single hybrid plant was selected from each cross-combination for three rounds of backcrossing with the corresponding maternal wheat cultivar. The transgene was detected in all four F1 BC3 combinations, but stress-inducible transgene expression was found in only three of the four combinations. Under well-watered conditions, the phenotypes and grain yield components of the F2 BC3 transgene-expressing lines were similar to those of corresponding recurrent parents and null-segregants. Under severe drought conditions, the backcross lines demonstrated 12-18% higher survival rates than the corresponding control plants. Two from four F3 BC3 transgenic lines showed significantly higher yield (18.9% and 21.5%) than control plants under limited water conditions. There was no induction of transgene expression under cold stress, and therefore, no improvement of frost tolerance observed in the progenies of drought-tolerant F3 BC3 lines.
Australian Centre for Plant Functional Genomics, University of Adelaide, Urrbrae, SA, 5064, Australia.
Yuri
Y
Shavrukov
Australian Centre for Plant Functional Genomics, University of Adelaide, Urrbrae, SA, 5064, Australia.
Manahil
M
Baho
Australian Centre for Plant Functional Genomics, University of Adelaide, Urrbrae, SA, 5064, Australia.
Sergiy
S
Lopato
Australian Centre for Plant Functional Genomics, University of Adelaide, Urrbrae, SA, 5064, Australia.
Peter
P
Langridge
D000222:Adaptation, Physiological / Q000235:genetics*; D001315:Australia; D001939:Bread; D020090:Chromosome Segregation / Q000235:genetics; D003433:Crosses, Genetic; D055864:Droughts; D005615:Freezing; D018628:Gene Dosage; D018506:Gene Expression Regulation, Plant; D006824:Hybridization, Genetic; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D019076:Transgenes; D014908:Triticum / Q000235:genetics* / Q000254:growth & development / Q000502:physiology
D010940:Plant Proteins
DREB transcription factor; backcrossing; drought; frost; hybrids; transgenic wheat