Preliminary Study On Molecular Machnisim Of Weisiensin B Influencing Polar Auxin Transport In Arabidopsis Thaliana

Isodon plants, which are labiatae perennial herbs, shrubs, or sub-shrubs, create abundant, various secondary metabolites influencing growth of others or themselves thus contribute to ecological structure. Ent-kaurane diterpenoid, which has been isolated more than 400 kinds, is the most important one among those secondary metabolites. Polar auxin transport (PAT) is critical importance for auxin gradients, which modulates many aspects of plant development including organ patterning, apical dominance, phyllotaxy/inflorescence development, lateral root and various root form, vascular development, fruit mature, embryo development and garitive/light response, et al. Study on allelopathy of Ent-kaurane diterpenoids and its effects on PAT can offer reference and theoretical support to in-depth investigations on mechanism of secondary metabolites on PAT.Model plant Arabidopsis thaliana and Ent-kaurane diterpenoids weisiensin B were used in this project. Firstly, we evaluated allelopathy potential of weisiensin B by testing its effcets on root development and reactive oxygen accumulation in Arabidopsis thaliana. Continually, we observed its effects on auxin accumulation, mutants deficient in auxin polar transport carriers and auxin transport carriers response in transcription and translation level. Results are shown as follows:(1) 10?M,20?M,40?M weisiensin B inhibited primary root emergency and cell length.(2) 10?M,20?M,40?M weisiensin B decreased the total number of lateral root primordial and lateral root. As the number of lateral root decreased sharply, weisiensin B delayed lateral root development.(3) 20?M,40?M weisiensin B inhibited both length and number of root hairs, while 10?M weisiensin B just inhibited its length.(4) 10?M,20?M,40?M weisiensin B increased DR5::GUS response in columella, quiescent center and stele.(5) 10?M,20?M,40?M weisiensin B stimulated PIN1 and PIN2 transcription and expression, while inhibited PIN3, PIN7 and AUX1 in both transcription and translation level. Its effect on PIN4 dependent on time and was different between ranscription and translation level.(6) The inhibit effection of weisiensin B on primary root of Arabidopsis thaliana at at the concentration of 10?20?M was decreased when PIN2 was singal mutated or PIN2, PIN3 and PIN4 were multiple mutated or PIN3, PIN4 and PIN7 were multiple mutated. However, those mutation discussed above did not influence the inhibit effection of weisiensin B on lateral root of Arabidopsis thaliana.(7) The mutation of PIN4 did not influence the inhibit effection of weisiensin B on development of both primary root and lateral root in Arabidopsis thaliana.(8) Inhibit effection of weisiensin B on primary root of Arabidopsis thaliana at the concentration of 10?20?M and on lateral root at the concentration of 10?40?M were decreased when AUX1 was mutated.Ent-kaurane diterpenoids weisiensin B shows some allelopathy potential as it inhibits root development in Arabidopsis thaliana. It also influences auxin accumulation and auxin polar transport carrier response and distribution in root.