Auxin and gibberellin signaling cross-talk promotes hypocotyl xylem expansion and cambium homeostasis
| Autor: | Laura Ragni, Martin Bayer, Mehdi Ben-Targem, Dagmar Ripper |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
0106 biological sciences
0301 basic medicine chemistry.chemical_classification biology Physiology Secondary growth fungi food and beverages Xylem Plant Science biology.organism_classification Cell morphology 01 natural sciences Cell biology 03 medical and health sciences 030104 developmental biology chemistry Auxin Arabidopsis Vascular cambium Phloem Cambium 010606 plant biology & botany |
| Zdroj: | Journal of Experimental Botany. 72:3647-3660 |
| ISSN: | 1460-2431 0022-0957 |
| Popis: | During secondary growth, the thickening of plant organs, wood (xylem) and bast (phloem) is continuously produced by the vascular cambium. In Arabidopsis hypocotyl and root, we can distinguish two phases of secondary growth based on cell morphology and production rate. The first phase, in which xylem and phloem are equally produced, precedes the xylem expansion phase in which xylem formation is enhanced and xylem fibers differentiate. It is known that gibberellins (GA) trigger this developmental transition via degradation of DELLA proteins and that the cambium master regulator BREVIPEDICELLUS/KNAT1 (BP/KNAT1) and receptor like kinases ERECTA and ERL1 regulate this process downstream of GA. However, our understanding of the regulatory network underlying GA-mediated secondary growth is still limited. Here, we demonstrate that DELLA-mediated xylem expansion in Arabidopsis hypocotyl is mainly achieved through DELLA family members RGA and GAI, which promote cambium senescence. We further show that AUXIN RESPONSE FACTOR 6 (ARF6) and ARF8, which physically interact with DELLAs, specifically repress phloem proliferation and induce cambium senescence during the xylem expansion phase. Moreover, the inactivation of BP in arf6 arf8 background revealed an essential role for ARF6 and ARF8 in cambium establishment and maintenance. Overall, our results shed light on a pivotal hormone cross-talk between GA and auxin in the context of plant secondary growth. |
| Databáze: | OpenAIRE |
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