OsPRAF1调控水稻主根伸长的分子机制

根系是植物水分、养分吸收的主要器官。根系构型对稻谷产量有很大影响，为培育高产优质稻米,水稻根系发育基因的筛选和鉴定工作必须予以加强。本研究前期从9311和日本晴重组自交系的第四染色体上精细定位了1个新QTL—qPRL4调节主根长度，候选基因为OsPRAF1。OsPRAF1是水稻PRAF家族5个成员之一；PRAF属于RCC1（regulator of chromosome condensation 1）家族的一个亚家族，是植物特有的基因，生物学功能尚不清楚。典型的PRAF蛋白具有4个结构域：两个脂质结合结构域，PH结构域和FYVE锌指结构域，7个RCC1串联重复序列及BRX结构域，暗示PRAF对植物发育的重要性。本项目继续构建OsPRAF1的突变体及超表达株系，运用植物生物学方法，揭示OsPRAF1及其下游基因在水稻主根伸长及遗传进化中的作用，为构筑水稻理想根系构型提供理论依据和基因资源。

The root is the major organ of plants absorbing water and nutrients. Roots architecture has a great influence on the rice yield. In order to produce more high quality of rice in limited land, the screening, identifying and cloning of the roots development-related genes in rice have to be strengthened. .Here, we fine-mapped a novel QTL for regulating primary root length with recombinant inbred lines from 9311 and Nipponbare, and confirmed OsPRAF1 as the candidate gene for qPRL4 on chromosome 4. OsPRAF1 is one of 5 members of the PRAF subfamily of the RCC1 (regulator chromosome condensation 1) family. In both dicot Arabidopsis and monocot rice, the biological functions of PRAF family remain completely unknown. PRAF proteins typically have four characteristic domains: two lipid-binding domains, the PH domain (pleckstrinhomology) and the FYVE (Fab1,YOTB,Vac1and EEA1) zinc-finger domain, seven repeats of the RCC1 (regulator of chromatin condensation) motif, and finally, a C-terminal BRX/DZC (brevis radix/disease resistance, zinc finger, chromosome condensation) domain, suggest that its funcntion is important for plant devolpment. In this project, we continue to investigate the roles of PRAF in regulating rice primary root elongation and genetic evolution, using plant biological methods in ospraf1 mutants and OsPRAF1-overexpressing lines. Our research will provide new theoretical basis for constructing desired root architecture and noval gene resouces for breeding high yield and high quality of rice.