Lateral roots are an important means for the plant to increase its absorptive area and the volume of substrate exploited. Lateral roots originate in the pericycle, the outermost layer of the... Show moreLateral roots are an important means for the plant to increase its absorptive area and the volume of substrate exploited. Lateral roots originate in the pericycle, the outermost layer of the vascular cylinder, and by growing penetrate the overlaying cell layers before emergence. This process is mainly controlled by the plant hormone auxin. In this thesis we studied the putative role of three Arabidopsis (a model plant) genes: AIR1A, AIR1B and AIR3, which are specifically expressed in the outer cell layers at the sites of lateral root formation and emergence. AIR1A and AIR1B are putative plasma membrane associated proteins related structural proteins that are believed to link the plasma membrane to the cell wall. AIR3 encodes a putative serine protease belonging to the family of subtilisins. We provide genetic evidence of the link between lateral root formation and AIR1 gene expression. We also show that AIR3 is part of the nitrate-signalling network regulating lateral root growth. Show less
