Division of Applied Life Science (BK21 Program), Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Gyeongsang National University, Jinju 660-701, Korea.
Plant Mol Biol. 2013 May;82(1-2):39-50. doi: 10.1007/s11103-013-0033-4. Epub 2013 Mar 1.
Rice is cultivated in water-logged paddy lands. Thus, rice root hairs on the epidermal layers are exposed to a different redox status of nitrogen species, organic acids, and metal ions than root hairs growing in drained soil. To identify genes that play an important role in root hair growth, a forward genetics approach was used to screen for short-root-hair mutants. A short-root-hair mutant was identified and isolated by using map-based cloning and sequencing. The mutation arose from a single amino acid substitution of OsSNDP1 (Oryza sativa Sec14-nodulin domain protein), which shows high sequence homology with Arabidopsis COW1/AtSFH1 and encodes a phosphatidylinositol transfer protein (PITP). By performing complementation assays with Atsfh1 mutants, we demonstrated that OsSNDP1 is involved in growth of root hairs. Cryo-scanning electron microscopy was utilized to further characterize the effect of the Ossndp1 mutation on root hair morphology. Aberrant morphogenesis was detected in root hair elongation and maturation zones. Many root hairs were branched and showed irregular shapes due to bulged nodes. Many epidermal cells also produced dome-shaped root hairs, which indicated that root hair elongation ceased at an early stage. These studies showed that PITP-mediated phospholipid signaling and metabolism is critical for root hair elongation in rice.
水稻在淹水的稻田中种植。因此，与在排水土壤中生长的根毛相比，水稻表皮层上的根毛暴露于不同的氮物种、有机酸和金属离子的氧化还原状态。为了鉴定在根毛生长中起重要作用的基因，采用正向遗传学方法筛选短根毛突变体。通过基于图谱的克隆和测序，鉴定并分离出一个短根毛突变体。该突变是由 OsSNDP1（水稻 Sec14-类钙网蛋白域蛋白）中的单个氨基酸取代引起的，它与拟南芥 COW1/AtSFH1 具有高度序列同源性，并编码一个磷酸肌醇转移蛋白（PITP）。通过与 Atsfh1 突变体进行互补测定，我们证明 OsSNDP1 参与根毛的生长。利用冷冻扫描电子显微镜进一步表征 Ossndp1 突变对根毛形态的影响。在根毛伸长和成熟区检测到异常形态发生。许多根毛分叉且形状不规则，节点凸起。许多表皮细胞也产生了圆顶状的根毛，这表明根毛伸长在早期就停止了。这些研究表明，PITP 介导的磷脂信号转导和代谢对水稻根毛伸长至关重要。
