Instituto de Biología Molecular y Celular de Plantas (Consejo Superior de Investigaciones Científicas-Universitat Politècnica de Valencia), C/Ingeniero Fausto Elio s/n Edif. 8E, Valencia, 46022, Spain.
Plant J. 2022 Dec;112(5):1281-1297. doi: 10.1111/tpj.16014. Epub 2022 Nov 19.
The tapetum is a specialized layer of cells within the anther, adjacent to the sporogenous tissue. During its short life, it provides nutrients, molecules and materials to the pollen mother cells and microsporocytes, being essential during callose degradation and pollen wall formation. The interaction between the tapetum and sporogenous cells in Solanum lycopersicum (tomato) plants, despite its importance for breeding purposes, is poorly understood. To investigate this process, gene editing was used to generate loss-of-function mutants that showed the complete and specific absence of tapetal cells. These plants were obtained targeting the previously uncharacterized Solyc03g097530 (SlTPD1) gene, essential for tapetum specification in tomato plants. In the absence of tapetum, sporogenous cells developed and callose deposition was observed. However, sporocytes failed to undergo the process of meiosis and finally degenerated, leading to male sterility. Transcriptomic analysis conducted in mutant anthers lacking tapetum revealed the downregulation of a set of genes related to redox homeostasis. Indeed, mutant anthers showed a reduction in the accumulation of reactive oxygen species (ROS) at early stages and altered activity of ROS-scavenging enzymes. The results obtained highlight the importance of the tapetal tissue in maintaining redox homeostasis during male gametogenesis in tomato plants.
绒毡层是花药中紧邻孢原组织的一层特化细胞。在其短暂的生命周期中，它为花粉母细胞和小孢子提供营养、分子和物质，在胼胝质降解和花粉壁形成过程中至关重要。尽管在育种方面具有重要意义，但茄属植物（番茄）中绒毡层与孢原细胞之间的相互作用仍知之甚少。为了研究这个过程，我们使用基因编辑技术生成了功能丧失型突变体，这些突变体表现出绒毡层细胞完全且特异性缺失。我们靶向之前未被表征的 Solyc03g097530（SlTPD1）基因生成了这些植物，该基因对于番茄中绒毡层的特化是必需的。在没有绒毡层的情况下，孢原细胞发育并观察到胼胝质的沉积。然而，小孢子未能经历减数分裂过程，最终退化，导致雄性不育。对缺乏绒毡层的突变体花药进行的转录组分析显示，一组与氧化还原稳态相关的基因下调。实际上，突变体花药在早期阶段活性氧（ROS）的积累减少，并且 ROS 清除酶的活性发生改变。这些结果强调了绒毡层组织在维持番茄植物雄性配子发生过程中的氧化还原稳态中的重要性。
