Instituto de Biología Molecular y Celular de Plantas, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Camino de Vera, Valencia, 46022, Spain.
Department of Biology, Algoma University, 1520 Queen Street East, Sault Ste Marie, ON, P6A 2G4, Canada.
New Phytol. 2021 Jul;231(2):679-694. doi: 10.1111/nph.17399. Epub 2021 May 20.
Cutin and suberin are lipid polyesters deposited in specific apoplastic compartments. Their fundamental roles in plant biology include controlling the movement of gases, water and solutes, and conferring pathogen resistance. Both cutin and suberin have been shown to be present in the Arabidopsis seed coat where they regulate seed dormancy and longevity. In this study, we use accelerated and natural ageing seed assays, glutathione redox potential measures, optical and transmission electron microscopy and gas chromatography-mass spectrometry to demonstrate that increasing the accumulation of lipid polyesters in the seed coat is the mechanism by which the AtHB25 transcription factor regulates seed permeability and longevity. Chromatin immunoprecipitation during seed maturation revealed that the lipid polyester biosynthetic gene long-chain acyl-CoA synthetase 2 (LACS2) is a direct AtHB25 binding target. Gene transfer of this transcription factor to wheat and tomato demonstrated the importance of apoplastic lipid polyesters for the maintenance of seed viability. Our work establishes AtHB25 as a trans-species regulator of seed longevity and has identified the deposition of apoplastic lipid barriers as a key parameter to improve seed longevity in multiple plant species.
角质层和木栓质是沉积在特定质外体隔室中的脂类聚酯。它们在植物生物学中的基本作用包括控制气体、水和溶质的运动，并赋予对病原体的抗性。角质层和木栓质都存在于拟南芥种子的种皮中，它们调节种子休眠和寿命。在这项研究中，我们使用加速和自然老化的种子分析、谷胱甘肽氧化还原电势测量、光学和透射电子显微镜以及气相色谱-质谱联用技术，证明了增加种皮中脂类聚酯的积累是 AtHB25 转录因子调节种子通透性和寿命的机制。在种子成熟过程中的染色质免疫沉淀揭示了长链酰基辅酶 A 合成酶 2 (LACS2) 是直接与 AtHB25 结合的脂质聚酯生物合成基因靶标。将这种转录因子基因转移到小麦和番茄中，证明了质外体脂类聚酯对于维持种子活力的重要性。我们的工作确立了 AtHB25 作为种子寿命的跨物种调节剂，并确定了质外体脂类屏障的沉积是提高多种植物种子寿命的关键参数。
