Local regulation of auxin transport in root-apex transition zone mediates aluminium-induced Arabidopsis root growth inhibition.
|Year of publication
|Article in Periodical
|Magazine / Source
|The Plant Journal
|MU Faculty or unit
|full text access
|aluminium; auxin transport; PIN1; root growth; root-apex transition zone
|Aluminium (Al) stress is a major limiting factor for worldwide crop production in acid soils. In Arabidopsis thaliana, the TAA1-dependent local auxin biosynthesis in the root-apex transition zone (TZ), the the major perception site for Al toxicity, is crucial for the Al-induced root growth inhibition, while the mechanism underlying Al-regulated auxin accumulation in the TZ is not fully understood. In this study, the role of auxin transport in Al-induced local auxin accumulation in the TZ and root growth inhibition was investigated. Our results showed that PIN-FORMED (PIN) proteins such as PIN1, PIN3, PIN4 and PIN7, and AUX1/LAX proteins such as AUX1, LAX1 and LAX2 were all ectopically up-regulated in the root-apex TZ in response to Al stress, and co-ordinately regulate the local auxin accumulation in the TZ and root growth inhibition. The ectopic up-regulation of PIN1 in the TZ under Al stress was regulated by both ethylene and auxin, with auxin signalling acting downstream of ethylene. Al-induced PIN1 up-regulation and auxin accumulation in the root-apex TZ was also regulated by the calossin-like protein BIG. Together, these studies provide insight about how Al stress induces local auxin accumulation in the TZ and root-growth inhibition through the local regulation of auxin transport.