The Genetic Study On Leaf Angle Gene TaIAA15s In Wheat

Wheat(Triticum aestivum,2n=6x=42,AABBDD)is an important staple food,providing approximately 40% of the world's population,and it is also the most widely planted and high-yielding food crop in China.In addition to being used as food,its use can be extended to wine,biofuel,medical and other fields.Ensuring the stability and high yield of wheat is not only related to the food security of our country and even the whole world,but also an important guarantee of chemical industry and animal husbandry.The plant type and yield characters of crops are the agronomic characters that breeders are more concerned about.The angle between the leaf and the main stem,that is,the angle between the leaf,is of great significance to the plant type spatial structure and planting density of crops by affecting the efficiency of leaf photosynthesis.The spatial structure of plant type of crops has an important influence on the planting density of crops.The angle between the leaf and the main stem affects the efficiency of leaf photosynthesis.There have been more in-depth studies on the leaf angle in maize and rice,but so far,there are few genes controlling the leaf angle in wheat,and the research on the molecular mechanism is more limited.The gene in this study is an auxin responsive gene,which is homologous to IAA15 in rice and Arabidopsis thaliana,so I named it TaIAA15.In this study,from the cut-in point of wheat TaIAA15 s gene,we deeply studied the functional regulation mechanism of this gene and explored the molecular genetic regulation mechanism of wheat plant type formation.our results are as follows:The angle between leaves of rice lines overexpressing TaIAA15 s gene increased and the plant height decreased significantly.The results of subcellular localization showed that TaIAA15 s protein was located in the nucleus and was a nuclear-localized transcriptional suppressor.The results of seed testing data of agronomic characters showed that the leaf angle of rice lines overexpressing TaIAA15 s gene was significantly larger than that of wild type,plant height decreased significantly,and the number of primary and secondary branches,effective grains,total grains and 1000-grain weight decreased significantly.Gene structure analysis showed that TaIAA15-3A and TaIAA15-3B had 90% similarity,with 5 exons and 4 introns,encoding 193 amino acid proteins.TaIAA15-3D has three exons and two introns,which encodes a protein of 176 amino acids.TaIAA15-3D is shorter than TaIAA15-3A/-3B protein,retaining the AUX/IAA conserved domains I,II,III and IV,but missing the C-terminal nuclear localization signal in IV.The results of Real-time PCR showed that the expression of TaIAA15 s in different tissues of wheat from high to low was leaf > glume > stem > ear > pistil > root > stamen,and TaIAA15 s was highly expressed in stems and leaves,but less in roots and stamens.After 7-day-old CS wheat seedlings were treated with 10?M IAA,the results showed that the transcriptional level of TaIAA15-3A/B was higher than that of TaIAA15-3D,and the highest expression occurred at 2 hours after IAA treatment.This indicates that the expression of TaIAA15 s gene in common wheat is induced by auxin,and the analysis of cis-acting elements on the upstream 1500 bp promoter of the gene coding region shows that there are differences in the type and number of cis-acting elements contained in the three homologous genes,which means that the expression of TaIAA15-3A,-3B and-3D may be different because of these elements.Using 24 common wheat materials to analyze the polymorphism of TaIAA15-3A,TaIAA15-3B and TaIAA15-3D,it was found that four SNPs,in intron 3 and intron 4 of TaIAA15-3A formed four haplotypes,namely Hap-A-I?IV.Most common wheat contain haplotype Hap-A-I,and Hap-A-I is also found in tetraploid wheat.TaIAA15-3B detected that 12 SNPs and one 32 bp indel,formed 7 haplotypes,namely Hap-B-I?VII.In common wheat,Hap-B-I-III,tetraploid wheat is mainly Hap-B-IV-VII.Wild relatives are mainly32 bp indel,common wheat is mainly 32 bp deletion,only Wenmai4 and Laizhou953 have32 bp indel.TaIAA15-3D detected that 8 SNPs,formed three haplotypes,namely Hap-D-IIII.Hap-D-II is mainly found in wild ancestral species and common wheat.Meanwhile,association analysis showed that TaIAA15-3B divided 186 local varieties and 180 extended varieties into two main haplotypes,namely Hap-B-II and Hap-B-III.Hap-B-II is the main haplotype in common wheat(67%),while Hap-B-III is the main haplotype in local varieties(87%),indicating that modern breeding gives priority to Hap-B-II.The correlation analysis of agronomic characters of 132 commercially bred varieties and 139 local varieties in different environments and years showed that Hap-B-III had longer panicle length in local varieties,while in commercially bred varieties,Hap-B-II had shorter plant height and shorter panicle length,but 1000-grain weight increased.Using 49 high-generation wheat lines cultivated in our laboratory,2 Aikang 58 mutants,Aikang 58 and Laizhou 953,based on the wheat 55 K SNP chip data,the highgeneration lobular angle line cultivated by our project(Bolera/Yanzhan 1)/Wennong 9carries haplotypes with small leaf angles.These haplotypes can be used as molecular markers to track the genotypes of hybrid offspring and shorten the breeding cycle.In summary,there was a significant correlation between TaIAA15-3B gene and leaf angle,plant type and yield of wheat.This study revealed that the auxin-related gene TaIAA15 s can affect the plant type of wheat and rice.