| Cuttage is one of the main approaches for plant vegetative propagation,and also an important afforestation method.Formation of adventitious root is the key step determining survival rate of cottage.Salt stress repress the formation of adventitious root and thus inhibit plant growth and development.Previous studies analyzed transcripomic dynamics response to salt stress in forest trees such as poplar.The molecular mechanisms underlying adventitious generation have also been revealed through identifying and analyzing master regulatory genes.However,the influence of salt stress on gene expression patterns and subsequent regulation of adventitious root formation remains unknown.In this study,we compared gene expression patterns during adventitious root formation between normal and salt-stress conditions in Salix matsudana Koidz.The results showed that a set of genes involved in cytokinin biosynthesis,auxin signal transduction,adventitious root generation exhibited similar changing models.In contrast,a group of genes demonstrated different changing patterns between normal and salt-stress conditions.This gene group contained type-A ARR which encodes a negative regulator of cytokinin signaling,PIN1 and LAX2 which participate in auxin transport,RGA1 and RGL2 that mediate GA signaling.The group also include genes regulating root meristem establishment,cell cycle and salt stress response.Our results indicated that NaCl stress repressed adventitious formation by affecting auxin transport,cytokinin and GA signaling,and suppressing cell cycle and root-meristem establishment.Moreover,the gene encoding GI,the negative regulator of SOS system,was down-regulated.Expression levels of genes involved in ROS removal and osmic homeostasis were increased.The results showed that SOS system and ROS removal and osmic homeostasis pathways were activated in response to NaCl stress. |
