Department of Soil and Plant Microbiology, Estación Experimental del Zaidín (EEZ), CSIC, Calle Profesor Albareda n◦1, 18008, Granada, Spain.
Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora" (IHSM "La Mayora"), Universidad de Málaga-Consejo Superior de Investigaciones Cientificas (UMA-CSIC), Campus Teatinos, 29010, Málaga, Spain.
Plant Physiol Biochem. 2024 Oct;215:109019. doi: 10.1016/j.plaphy.2024.109019. Epub 2024 Aug 6.
Arbuscular mycorrhizal (AM) fungi improve plant growth, nutrition, fitness and stress tolerance while AM fungi obtain carbohydrates and lipids from the host. This whole process of mutual benefit requires substantial alterations in the structural and functional aspects of the host root cells. These modifications ultimately culminate in the formation of arbuscules, which are specialized intraradical and highly branched fungal structures. Arbuscule-containing cells undergo massive reprogramming to hosting arbuscule and members of the GRAS transcription factor family have been characterized as AM inducible genes which play a pivotal role in these process. Here, we show a functional analysis for the GRAS transcription factor SCL3/SlGRAS18 in tomato. SlGRAS18 interacts with SlDELLA, a central regulator of AM formation. Silencing of SlGRAS18 positively impacts arbuscule development and the improvement in symbiotic status, favouring flowering and therefore progress in the formation and development of fruits in SlGRAS18 silenced plants which parallel to a discernible pattern of mineral nutrient redistribution in leaves. Our results advance the knowledge of GRAS transcription factors involved in the formation and establishment of AM symbiosis and provide experimental evidence for how specific genetic alterations can lead to more effective AM symbiosis.
丛枝菌根 (AM) 真菌在改善植物生长、营养、适应能力和抗逆性的同时，从宿主中获取碳水化合物和脂质。这种互利共生的全过程需要宿主根细胞的结构和功能方面发生实质性的改变。这些改变最终导致了丛枝的形成，这是一种特殊的根内和高度分支的真菌结构。含有丛枝的细胞经历了大规模的重编程来容纳丛枝，而 GRAS 转录因子家族的成员被表征为 AM 诱导基因，在这些过程中发挥着关键作用。在这里，我们展示了番茄中 GRAS 转录因子 SCL3/SlGRAS18 的功能分析。SlGRAS18 与 SlDELLA 相互作用，后者是 AM 形成的中央调节剂。SlGRAS18 的沉默对丛枝的发育和共生状态的改善有积极影响，有利于开花，从而促进 SlGRAS18 沉默植物的果实的形成和发育，这与叶片中矿物质养分再分配的明显模式相平行。我们的结果推进了参与 AM 共生形成和建立的 GRAS 转录因子的知识，并提供了实验证据，证明了特定的遗传改变如何导致更有效的 AM 共生。
