TEMPRANILLO Reveals the Mesophyll as Crucial for Epidermal Trichome Formation

Plant Physiology
Luis Matías-HernándezSoraya Pelaz

Abstract

Plant trichomes are defensive specialized epidermal cells. In all accepted models, the epidermis is the layer involved in trichome formation, a process controlled by gibberellins (GAs) in Arabidopsis rosette leaves. Indeed, GA activates a genetic cascade in the epidermis for trichome initiation. Here we report that TEMPRANILLO (TEM) genes negatively control trichome initiation not only from the epidermis but also from the leaf layer underneath the epidermis, the mesophyll. Plants over-expressing or reducing TEM specifically in the mesophyll, display lower or higher trichome numbers, respectively. We surprisingly found that fluorescently labeled GA3 accumulates exclusively in the mesophyll of leaves, but not in the epidermis, and that TEM reduces its accumulation and the expression of several newly identified GA transporters. This strongly suggests that TEM plays an essential role, not only in GA biosynthesis, but also in regulating GA distribution in the mesophyll, which in turn directs epidermal trichome formation. Moreover, we show that TEM also acts as a link between GA and cytokinin signaling in the epidermis by negatively regulating downstream genes of both trichome formation pathways. Overall, these results call for a re-...Continue Reading

Citations

Jul 17, 2019·The Plant Journal : for Cell and Molecular Biology·Andrea E Aguilar-JaramilloPaula Suárez-López
Jul 28, 2020·Journal of Experimental Botany·Johanna StockHans-Peter Mock
Feb 28, 2019·Chemical Science·Shira WexlerRoy Weinstain
Dec 8, 2017·Physiologia Plantarum·Sylwia GłazowskaJan K Schjoerring
Oct 29, 2020·The Plant Journal : for Cell and Molecular Biology·Michela OsnatoSoraya Pelaz
Feb 3, 2021·BMC Plant Biology·Xiaojing WangLitang Lv
Apr 9, 2021·The Plant Cell·Sara I ZandalinasRon Mittler
Feb 26, 2021·Annals of Botany·Harold Suárez-BaronNatalia Pabón-Mora

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