磷是植物生长发育所必需的大量元素之一。目前土壤缺磷已经成为制约农业生产的一个重要因子。植物在低磷条件下生长时， 会产生一系列应答反应。根毛形成的增加是植物对低磷胁迫的一个主要适应性反应，可以增加根系的表面积以有利于植物更好地吸收土壤养分。但目前关于低磷信号是如何增加根毛形成的分子机制并不清楚。在前期的工作中，我们通过对乙烯信号相关的突变体的转录本分析，鉴定得到一系列位于乙烯下游参与低磷胁迫诱导根毛形成的候选基因。过表达其中AT-HOOK蛋白AHL17和AHL28会导致植物形成大量根毛。在低磷条件下，这些过表达植株的根毛形成进一步增加。本项目将通过阐明AHL17和AHL28的生化功能，寻找其下游靶基因，鉴定其互作蛋白，研究其与已知的根毛发育相关的重要分子组分的关系等，来全面探究这两个AHL蛋白介导低磷胁迫诱导根毛形成的分子机制。本研究也将为培育高效利用土壤养分的转基因作物提供新的思路。

Phosphorus is an essential macronutrient required for plant growth and development. Today, phosphate (Pi) deficiency in soil has become an important constraint for agricultural production. When grown under Pi deficiency, plants trigger an array of adaptive responses. One major response is the enhancement of root hair development, which increases root surafce area to make plants better absorb nutreints from soil. The molecular mechanism regulating this response, however, remains largely unknown. In our previous work, we identified a group of candidate genes that might be involved in Pi deficiency-induced roo hair development through the analysis of transcriptomes of ethylene-related mutants grown under Pi deficiency. Two of these genes, which encode AHL (AT-HOOK) proteins, AHL17 and AHL28,.when overexpressed, cause plants to overproduce root hairs. This phenotype is further enhanced under Pi deficiency. The aims of this research are to understand the functions of these two proteins in mediating Pi deficiency-induced root hair development by elucidating their biochemical functions, identifying their interacting proteins and target genes, and their interactions with the key transcription factors that are involved in the control of root hair development. The results obtained from this research will also provide new strategies for genetic engineering of crops with high efficiency in nutrient uptake.