Lab Plant, Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Fortaleza-CA, 60451-970, Brazil.
Departamento de Botânica, Instituto de Ciências Biológicas, Universidade de Brasília, Asa Norte, Brasília-DF, 70910-900, Brazil.
Plant J. 2023 Jun;114(5):1093-1114. doi: 10.1111/tpj.16214. Epub 2023 Apr 13.
Every plant organ contains tens of different cell types, each with a specialized function. These functions are intrinsically associated with specific metabolic flux distributions that permit the synthesis of the ATP, reducing equivalents and biosynthetic precursors demanded by the cell. Investigating such cell-type-specific metabolism is complicated by the mosaic of different cells within each tissue combined with the relative scarcity of certain types. However, techniques for the isolation of specific cells, their analysis in situ by microscopy, or modeling of their function in silico have permitted insight into cell-type-specific metabolism. In this review we present some of the methods used in the analysis of cell-type-specific metabolism before describing what we know about metabolism in several cell types that have been studied in depth; (i) leaf source and sink cells; (ii) glandular trichomes that are capable of rapid synthesis of specialized metabolites; (iii) guard cells that must accumulate large quantities of the osmolytes needed for stomatal opening; (iv) cells of seeds involved in storage of reserves; and (v) the mesophyll and bundle sheath cells of C4 plants that participate in a CO concentrating cycle. Metabolism is discussed in terms of its principal features, connection to cell function and what factors affect the flux distribution. Demand for precursors and energy, availability of substrates and suppression of deleterious processes are identified as key factors in shaping cell-type-specific metabolism.
每个植物器官都包含数十种不同的细胞类型，每种细胞类型都具有特定的功能。这些功能与特定的代谢通量分布密切相关，这些分布允许合成细胞所需的 ATP、还原当量和生物合成前体。研究这种细胞类型特异性代谢非常复杂，因为每个组织中都存在不同的细胞马赛克，而且某些类型的细胞相对较少。然而，用于分离特定细胞的技术、通过显微镜对其进行原位分析，或对其功能进行计算机模拟，都使得深入了解细胞类型特异性代谢成为可能。在描述我们对已经深入研究的几种细胞类型的代谢了解之前，本文介绍了分析细胞类型特异性代谢所使用的一些方法；（i）叶片源和汇细胞；（ii）能够快速合成特殊代谢物的腺毛；（iii）必须积累大量用于打开气孔所需渗透物的保卫细胞；（iv）参与储存储备的种子细胞；以及（v）参与 CO2 浓缩循环的 C4 植物的叶肉和束鞘细胞。代谢是根据其主要特征、与细胞功能的联系以及影响通量分布的因素来讨论的。前体和能量的需求、底物的可用性以及抑制有害过程被确定为塑造细胞类型特异性代谢的关键因素。
