Department of Plant and Environmental Sciences, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 9190401, Israel.
Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel.
Plant Physiol. 2023 Aug 31;193(1):611-626. doi: 10.1093/plphys/kiad350.
Seeds are an essential food source, providing nutrients for germination and early seedling growth. Degradation events in the seed and the mother plant accompany seed development, including autophagy, which facilitates cellular component breakdown in the lytic organelle. Autophagy influences various aspects of plant physiology, specifically nutrient availability and remobilization, suggesting its involvement in source-sink interactions. During seed development, autophagy affects nutrient remobilization from mother plants and functions in the embryo. However, it is impossible to distinguish between the contribution of autophagy in the source (i.e. the mother plant) and the sink tissue (i.e. the embryo) when using autophagy knockout (atg mutant) plants. To address this, we employed an approach to differentiate between autophagy in source and sink tissues. We investigated how autophagy in the maternal tissue affects seed development by performing reciprocal crosses between wild type and atg mutant Arabidopsis (Arabidopsis thaliana) plants. Although F1 seedlings possessed a functional autophagy mechanism, etiolated F1 plants from maternal atg mutants displayed reduced growth. This was attributed to altered protein but not lipid accumulation in the seeds, suggesting autophagy differentially regulates carbon and nitrogen remobilization. Surprisingly, F1 seeds of maternal atg mutants exhibited faster germination, resulting from altered seed coat development. Our study emphasizes the importance of examining autophagy in a tissue-specific manner, revealing valuable insights into the interplay between different tissues during seed development. It also sheds light on the tissue-specific functions of autophagy, offering potential for research into the underlying mechanisms governing seed development and crop yield.
种子是一种重要的食物来源，为种子发芽和幼苗早期生长提供营养。种子和母体植物的降解事件伴随着种子的发育，包括自噬作用，它促进了溶酶体中的细胞成分的分解。自噬作用影响植物生理学的各个方面，特别是营养物质的可用性和再动员，表明其参与了源-库相互作用。在种子发育过程中，自噬作用影响来自母体植物的营养物质再动员，并在胚胎中发挥作用。然而，当使用自噬敲除（atg 突变体）植物时，很难区分自噬在源（即母体植物）和汇组织（即胚胎）中的贡献。为了解决这个问题，我们采用了一种区分源组织和汇组织中自噬的方法。我们通过在野生型和 atg 突变体拟南芥（Arabidopsis thaliana）植物之间进行正反交，研究了母体组织中的自噬如何影响种子发育。尽管 F1 幼苗具有功能性的自噬机制，但来自母体 atg 突变体的黄化 F1 植物生长缓慢。这归因于种子中蛋白质而非脂质积累的改变，表明自噬作用差异调节碳和氮的再动员。令人惊讶的是，母体 atg 突变体的 F1 种子发芽更快，这是由于种皮发育的改变。我们的研究强调了以组织特异性方式研究自噬的重要性，揭示了在种子发育过程中不同组织之间相互作用的有价值的见解。它还揭示了自噬的组织特异性功能，为研究控制种子发育和作物产量的潜在机制提供了可能性。
