Functional Verification Of TaFer-A1Gene On Wheat Chromosome1A And Development Of A Specific Molecular Marker Related With Drought Resistance

Wheat is the important food crop of China. Among a variety of non-biological factors affecting wheat production, drought is the most harmful one and has a increasing trend year by year. It is important to improve drought resistance of wheat. It will provide theoretical basises and methods for wheat drought resistance breeding, through the discovery of drought-related genes and development of drought-related molecular markers.In this study, Jinmai47wheat varieties was used as the material to clone the wheat iron-binding protein gene (TaFer-Al) located on chromosome1A.The gene was transformed into Arabidopsis for functional verification of NaCl and drought resistance. Two groups of extreme drought resistance of wheat varieties in germination period was used to analysis the sequence differences of TaFer-Al gene. Primer pairs were designed and150varieties (lines) with different drought resistance in germination stage was detected to develop TaFer-Al gene associated molecular markers. The results were as following:1. The overall average relative germination rate was significantly different among150varieties (lines). Based on the relative germination rate, there were five drought-grade varieties (lines), stronger resistance, strong resistance, middle resistance, weak resistance and weaker resistance, among the tested varieties. This five drought-grade varieties (lines) occupied8.7%、24.0%、38.0%、20.0、and9.3%in the detected ones respectively. Traits related seedling growth, such as root relative growth, dry weight of root under PEG-6000stress, shoot related growth were significant correlation with the relative germination. Root relative growth had the highest correlation (0.059) with relative germination.2. The wheat chromosome1A iron-binding protein gene(TaFer-Al) was transformed into Arabidopsis for salt and drought tolerance phenotype analysis. Under polyethylene glycol (PEG-6000) stress, the etiolation rate of transgenic seedlings was lower than the wild type. And the average root length of transgenic seedlings (11.56) was significantly longer than that of wild type (8.44)(P<0.05) under different concentrations of PEG-6000. But there showed no significant differences between the two types of Arabidopsis under NaCl stress. It indicated that the gene, TaFer-Al had the potential to improve drought resistance of plants.3. Sequence alignment of TaFer-Al gene in two groups of extreme drought resistance of wheat varieties. There existed seven variable sites, including six SNP loci and a Del/Ins sites among four wheat varieties. Five SNP loci occurred in the gene intron regions. Xinong2208occurred a SNP neutral mutation in the first exon of339bp, compared with the other three species. Compared to the weaker drought resistance varieties, the stronger ones existed a three consecutive nucleotides (TCT) insertion in the first intron409-41lbp region of TaFer-Al gene. It was consistent with the drought resistance of the tested wheat varieties. Based on this diffenrence, two alleles, named as TaFer-Al a and TaFer-Alb were found in TaFer-Al gene locus.4. Development of molecular marker related with drought resistance. A co-dominant molecular marker, FerAl-intrl was developed, based on the Del/Ins sites intron1region409-411bp of TaFer-Al gene. This marker, amplified167bp and170bp specific band in TaFer-Ala and TaFer-Alb respectively.150varieties (lines) with different drought resistance were detected by FerAl-intrl. The result showed that TaFer-Ala relative germination rate was significantly higher than that of TaFer-Alb (P<0.01). It indicted that FerAl-intrl can be used for identification of drought of wheat varieties (lines). And it further proved that the gene, TaFer-Al was related with drought resistance.This study identified and screened a number of wheat material with strong drought resistance. And it confirmed that TaFer-Al gene in Arabidopsis can significantly improve and enhance tolerance to drought stress. A co-dominant marker, FerAl-intrl was developed based on the TaFer-Al sequence between two groups of extreme drought resistance varieties. Two alleles, TaFer-Ala and TaFer-Alb were found in the TaFer-Al locus. TaFer-Ala relative germination rate was significantly higher than that of TaFer-Alb (P<0.01). It indicted that FerAl-intrl can be used for identification of drought of wheat varieties (lines).