Transcriptome changes in the cambial region of poplar P. Alba l.) in response to water deficit

A transcriptome analysis of the P. alba cambial region was performed with the aim of unravelling the gene network underlying the response to water deficit within the cambium and the differentiating derivative cambial cells. Water stress was induced on a one-year-old Populus alba plants by withholding water for 9 days. At that time, leaf predawn water potential fell to -0,8 MPa resulting in a significant reduction of the stomatal conductance, CO2 assimilation and consistent increment of stem shrinkage. These effects were almost fully reversed by re-hydration. The water deficit resulted in changes in gene expression that affected a few functional categories such as protein metabolism, cell wall metabolism, stress response, transporters and transcriptional regulation. The function of up- and down-regulated genes is discussed considering the physiological response of the plants to water deficit.