Data_Sheet_1_A Phloem-Expressed PECTATE LYASE-LIKE Gene Promotes Cambium and Xylem Development.pdf

The plant vasculature plays essential roles in the transport of water and nutrients and is composed of xylem and phloem, both of which originate from undifferentiated cells found in the cambium. Development of the different vascular tissues is coordinated by hormonal and peptide signals and culminates in extensive cell wall modifications. Pectins are key cell wall components that are modified during cell growth and differentiation, and pectin fragments function as signals in defence and cell wall integrity pathways, although their role as developmental signals remains tentative. Here, we show that the pectin lyase-like gene PLL12 is required for growth of the vascular bundles in the Arabidopsis inflorescence stem. Although PLL12 was expressed primarily in the phloem, it also affected cambium and xylem growth. Surprisingly, PLL12 overexpression induced ectopic cambium and xylem differentiation in the inflorescence apex and inhibited development of the leaf vasculature. Our results raise the possibility that a cell wall-derived signal produced by PLL12 in the phloem regulates cambium and xylem development.

植物维管组织在水分和营养物质的运输中扮演着至关重要的角色，由木质部和韧皮部组成，两者均源自形成层中的未分化细胞。不同维管组织的发育受到激素和肽类信号的协调调控，并最终导致细胞壁的广泛改造。果胶是细胞壁的关键组分，在细胞生长和分化过程中发生修饰，而果胶碎片则作为防御和细胞壁完整性途径中的信号分子发挥作用，尽管其在发育信号中的角色尚属推测。在本研究中，我们揭示了pectin lyase-like基因PLL12对于拟南芥花梗中维管束的生长是必需的。尽管PLL12主要在韧皮部表达，但它也影响了形成层和木质部的生长。令人惊讶的是，PLL12的过表达诱导了花梗顶端的异位形成层和木质部分化，并抑制了叶片维管组织的发育。我们的研究结果提出了这样一种可能性，即由PLL12在韧皮部产生的细胞壁衍生的信号分子调控了形成层和木质部的发育。