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Plant Physiology：拟南芥茎尖分生组织大小调控和叶片起始

已有 5395 次阅读 2018-11-10 09:05 |个人分类:每日摘要|系统分类:论文交流

EPFL signals in the boundary region of the SAM restrict its size and promote leaf initiation

First author: Pawel Z. Kosentka; Affiliations: University of Tennessee (田纳西大学): Knoxville, USA

Corresponding author: Elena D. Shpak

The shoot apical meristem (SAM; 茎尖分生组织) enables the formation of new organs throughout the life of a plant. ERECTA family (ERf) receptors restrict SAM size and promote initiation of leaves while simultaneously supporting establishment of correct phyllotaxy (叶序). In the epidermis (表皮) and during organ elongation ERf activity is regulated by a family of Epidermal Patterning Factor-Like (EPFL) secreted cysteine-rich (富含半胱氨酸) small proteins. Here we show that ERfs play a critical role in communication between the SAM leaf boundary (叶边界) and the central zone in Arabidopsis thaliana. Ectopic expression of ERECTAin the central zone using the CLAVATA3promoter is sufficient to restrict meristem size and promote leaf initiation. Genetic analysis demonstrated that four putative ligands: EPFL1, EPFL2, EPFL4, and EPFL6 function redundantly in the SAM. These genes are expressed at the SAM-leaf boundary and in the peripheral zone. Previously EPFL4 and EPFL6 have been linked with elongation of aboveground organs. Here we demonstrate that EPFL1 and EPFL2 promote organ elongation as well. In addition, we show that expression of ERECTAin the central zone of the SAM has a strong impact on elongation of internodes (节间) and pedicels (花梗) and growth of leaves. These results suggest that ERfs can stimulate organ growth cell non-autonomously (细胞非自主性).

茎间分生组织SAM能够保证植物在整个生活史中新器官的形成。ERECTA家族ERf受体蛋白限制SAM的大小，并在促进叶片起始的同时保证正确叶序的形成。在植物表皮和器官伸长过程中ERf的活性受到类表皮模式因子EPFL分泌的富含半胱氨酸小蛋白调控。本文的研究显示拟南芥ERfs在SAM叶边界和中心区域之间的交流中发挥重要作用。利用CLAVATA3启动子在中心区域的异位表达ERECTA基因能够限制分生组织的大小，促进叶片起始。遗传分析显示EPFL1、EPFL2、EPFL4和EPFL6四个配基在SAM中发挥的功能冗余。这些基因均在SAM与叶片的边界以及周边区域表达。先前的研究显示EPFL4和EPFL6作用于地上器官的伸长。作者进一步表明EPFL1和EPFL2同样也能促进器官的伸长。另外，ERECTA基因在SAM中心区域的表达对于节间和花梗的伸长以及叶片的生长具有比较强的效应。本文的研究结果揭示了ERfs可以细胞非自主性刺激植物器官生长。