Abstract
Exogenous auxins supplementation plays a central role in the formation of adventitious roots (AR) for several plant species. However, the molecular mechanisms underlying the process of adventitious rooting are still not completely understood and many plants with economic value, including several olive cultivars, exhibit a recalcitrant behavior towards cutting propagation, which limits its availability in plant nurseries. PIN-formed proteins are auxin efflux transporters that have been widely characterized in several plant species due to their involvement in many developmental processes including root formation. The present study profiled the expression of the OePIN1a-c, OePIN2b, OePIN3a-c, OePIN5a-c, OePIN6, and OePIN8 gene members during indole-3-butyric acid (IBA)-induced in vitro adventitious rooting using the olive cultivar ‘Galega vulgar’. Gene expression analysis by quantitative real time PCR (RT-qPCR) showed drastic downregulation of most transcripts, just a few hours after explant inoculation, in both nontreated and IBA-treated microcuttings, albeit gene downregulation was less pronounced in IBA-treated stems. In contrast, OePIN2b showed a distinct expression pattern being upregulated in both conditions, and OePIN5b was highly upregulated in IBA-induced stems. All transcripts, except OePIN8, showed different expression profiles between nontreated and IBA-treated explants throughout the rooting experiment. Additionally, high levels of reactive oxygen species (ROS) were observed soon after explant preparation, decreasing a few hours after inoculation. Altogether, the results suggest that wounding-related ROS production, associated with explant preparation for rooting, may have an impact on auxin transport and distribution via changes in OePIN gene expression. Moreover, the application of exogenous auxin may modulate auxin homeostasis through regulation of those genes, leading to auxin redistribution throughout the stem-base tissue, which may ultimately play an important role in AR formation.
Highlights
Auxins are an important group of phytohormones that influence cell division, cell elongation, and cell differentiation and have been widely reported to be involved in the control of plant growth and development [1,2,3]
Auxinsplay play a central in the control of adventitious rooting
Trying to understand whether whether auxin could transport could beinimpaired in difficult-to-root olivewe cultivars, wethe analyzed the of auxin transport be impaired difficult-to-root olive cultivars, analyzed expression expression of the olive
Summary
Auxins are an important group of phytohormones that influence cell division, cell elongation, and cell differentiation and have been widely reported to be involved in the control of plant growth and development [1,2,3]. Auxins were long believed to be mainly synthesized in the young leaves and apical meristem of the shoot [24], more recent studies found that both shoots and roots can produce auxins [25]. PAT is the major auxin distribution pathway, dispersing auxin from cell-to-cell in a slow and direct manner, and is determinant for the spatio-temporal dissemination of that molecule within tissues during plant development. This is achieved by establishing defined auxin gradients (auxin homeostasis), involving local auxin maxima or local auxin optima, which inhibit and promote, respectively, cell division, expansion, or differentiation [1,26,27,28,29]. There are three main classes of auxin membrane transporters mediating the PAT system: the influx carriers auxin permease
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
