Mechanism Of Auxin-mediated Adventitious Roots Formation In Arabidopsis Thaliana

Roots are fundamentally important organ in plants and support the growth of plants through anchoring the plants,absorbing water,storing nutrients and photoassimilates.Root system of seed plants are usually comprised of primary roots(PRs),lateral roots(LRs)and adventitious roots(ARs).The PR derives from radicle during germination,both ARs and LRs develop postembryonically.In contrast to LRs,ARs develop from different tissues and consequently from different cell types.The plant hormone auxin has long time been known to promote root formation,but it is not clear how auxin promotes the initiation of different ARs.Here we established the culture systems of different types ARs in Arabidopsis thaliana and analysed phenotypes of ARs in the mutants,which are altered in their ability to form LRs and ARs.A combination of the molecular markers in cell fate transition in the process of ARs formation were tracked.We report here that auxin response factor ARF6/8/7/19 regulate ARs formation via activate WOX11 in Arabidopsis thaliana.The IAA14(INDOLE-3-ACETIC ACID INDUCIBLE 14)-ARF7/19 module contributes to ARs formation of hypocotyls,but weakly contributes to the regeneration of ARs from isolated leaves.The WOX11/12(WUSCHELRELATED HOMEOBOX 11/12)-WOX5/7 and WOX11/12-LBD16(LATERAL ORGAN BOUNDARIES-DOMAIN 16)modules that contribute to the regeneration of ARs from isolated leaves are also involved in the formation of ARs of hypocotyl,while WOX11/ 12 does not contribute to the ARs formation induced by wounds of hypocotyl and PRs.Furthermore,ARF6/8/7/19 contribute to the formation of adventitious lateral roots in the soil.Above all,WOX11 is expressed during the initiation of different types of ARs,suggesting that WOX11 may be a universal transcription factor involved in the formation of ARs of different types.In summary,auxin regulates different types of ARs through different transcription factors.Plants will take different strategies pathway in response cues of different parts of plants.