Email: 2021060047@nwafu.edu.cn; huyingang@nwafu.edu.cn

Wheat is an important grain crop in the world, and the height of wheat plant is one of the important phenotypes to determine the yield, in which dwarf genes play a key role. The gibberellin-sensitive (GAR) dwarf gene Rht5 can reduce plant height and improve lodging resistance, but does not affect the coleoptile length and seedling viability, and can significantly increase the effective panicle number, panicle number and harvest coefficient, therefore, Rht5 mapping and gene mining are of great significance for wheat dwarf breeding.

Then two F2 populations derived from the crosses of Jinmai47 and Ningchun45 with Marfed M (Rht5) were employed to identify the genetic region of Rht5, and their derived lines were used to evaluate its efects on plant height and main agronomic traits. Rht5 was fine-mapped between markers Kasp-25 and Kasp-23, in approximately 1 Mb region on chromosome 3BS, which harbored 17 high-confidence annotated genes based on the reference genome of Chinese Spring (IWGSC RefSeq v1.1).

Combined with the recombinant inbred lines derived from the hybridization of Jinmai 47 and Mafed M, homozygant tall and short lines from different F3:4 isolated lines were selected for RNA-Seq sequencing, so as to mine genes related to stem development.

Among all possible genes, TraesCS3B02G025600 was suggested as a potential candidate gene of Rht5. There is a 30 bp deletion in the frist exon of its coding region was found in Marfed M, as compared to Jinmai47, Nicngchun45 and Chinese spring, which leaded to variations in amino acid sequence. It encodes a CYP450 protein which is a massive family contains plenty of members and is vital in the biosynthetic of phytohormones.

GA and BR were vital to the growth of plant, and a considerable number of genes involved in the biosynthesis and metabolism of GA and BR encoded CYP450 proteins. TraesCS3B02G025200 encoding fructosebisphosphate aldolase.

Fructose 1, 6-diphosphate aldolase is involved in glycolysis, glucose production and the Calvin cycle, providing energy and substances for plant growth and development.That two genes may be Rht5 candidate genes.

Screening Rht5 candidate genes and studying the mechanism of Rht5 dwarfism are of great significance for wheat dwarf breeding.