Fine Mapping And Candidate Gene Analysis Of High-Tillering And Dwarf Gene Htd(t) And Hairy Leaf Gene HL1in Rice

Tillering and plant height are two major agronomic traits affecting its architecture and further determine grain yield, they are the topics of functional genomic. The rice GuangCong from GuiZhou showed more tillers, dwarfer. softer and thinner leaf, longer and thinner grain. A F2segregation population composed of188individuals was constructed from the cross between GuangCong and MoXuegu. The quantitative trait loci (QTL) for high-tillering were analyzed in the F2population. A main QTL was detected on chromosome4, LOD is28.6, PVE is53.0%. By means of molecular marker technique. The high-tillering dwarf(t) gene was mapped between two InDel markers ID2and ID4on chromosome4within150kb. Within this region, there is a cloned gene HTD1, Which Controls rice tillering. Sequencing analysis of the D17/HTD1allele in GuangCong revealed that the1787th base was substituted from C to T, changing the596th amino acid from proline to leucine. So the htd(t) gene of GuangCong is htdl.The trichome on the leaf as a morphological feature is a very important agronomic traits in rice, which also has a great significance to genetically improved breeding. In many species, trichomes play a critical role in chemical defense of plant due to accumulation and secretion of alkaloids. Whereas in most of plants non-glandular trichomes function to enhance resistance in plants against abiotic stresses including extremely low and high temperatures, drought tolerance and protection of plant tissues from UV light, also improves plants resistance to biotic factors such as insect herbivores, etc. In this study, we chose an indica cultivar SWWR (hairy leaf), and two non-hairy japonica culivar Nipponbare and Ningl. Respectively, two segregation populations were constructed from the cross between the above-mentioned parents. Genetic analysis indicated that the hairy leaf was controlled by a single recessive gene. By bulked segregant analysis, the hairy leaf gene HL1was mapped between two SSR markers RM528and RM5988on chromosome6. The candidate region of HL1was finally narrowed down to a12.7kb interval, which is between Newly developed markers InDel WB17and WB23, Within this region, there is oniy one gene LOC_Os06g44750, which Coding a protein contained AP2domain Sequencing the target DNA region and comparing the counterpart Coding sequences between SWWR and Nipponbare revealed two nucleotide substitution (SNP1, SNP2) and a continuous deletion of three nucleotides (InDell) in a predicted rice gene, LOC_Os06g44750. SNP1was synonymous mutation. SNP2. a single nucleotide transition from C (Nipponbare) to A (SWWR), corresponding to an amino acid substitution from methionine to isoleucine. And InDell. three-bases of CAG were missed at where were the CAG repeated for Eight times.With the evidence of the association between the presence of one amino acid change (SNP2) and one amino acid deletion (InDel1) in LOC_Os06g44750and the hairy leaf phenotypes of SWWR, LOC_Os06g44750was most likely the candidate gene for HL1, Controlling trichome development.