植物凯氏带起源与功能分化研究进展

Research Progress on the Origin and Functional Differentiation of Plant Casparian Strip

摘要: 凯氏带是维管植物根部皮层细胞壁上特化的木质化带状增厚结构，作为根系质外体运输的关键屏障，在植物选择性吸收矿质元素、响应逆境胁迫以及植物–微生物互作中发挥着重要作用。该结构自被发现以来，长期被认为是维管植物高度保守的结构，但近年来研究逐渐揭示了其在不同植物类群间存在显著的结构、调控与功能分化。本文从进化发育生物学角度系统梳理相关研究进展，论述了凯氏带起源以及凯氏带形成的核心调控模块，阐明了凯氏带在不同植物类型中的发育特征和功能分化，包括内皮层和外皮层屏障的物种特异性、凯氏带响应非生物胁迫可塑性变化、凯氏带介导根系内生菌和根际微生物定殖与富集并参与共生固氮等过程。本文进一步探讨了现有研究的不足以及未来研究方向，以期为作物抗逆育种和养分高效利用提供理论参考。

Abstract: The casparian strip is a specialized lignified band-like thickening structure located in the cell walls of root cortical tissues in vascular plants. As a critical barrier regulating apoplastic transport in roots, it plays essential roles in the selective uptake of mineral nutrients, responses to abiotic stresses, and plant-microbe interactions. Since its discovery, the casparian strip has long been regarded as a highly conserved structure in vascular plants. However, recent studies have gradually revealed significant divergence in its structure, regulation, and function among different plant lineages. From the perspective of evolutionary developmental biology, this review systematically summarizes recent advances in the field, discusses the evolutionary origin of the casparian strip and the core regulatory modules governing its formation, and elucidates the developmental characteristics and functional diversification of casparian strips in different plant groups. These include species-specific differences in endodermal and exodermal barriers, the plastic responses of casparian strips to abiotic stresses, and the roles of casparian strips in mediating root endophyte and rhizosphere microbiota colonization and enrichment, as well as their involvement in symbiotic nitrogen fixation. Furthermore, this review discusses current limitations and future research directions, with the aim of providing theoretical references for crop breeding aimed at improving stress resistance and nutrient use efficiency.