Boyce Thompson Institute, Ithaca, New York 14853.
Boyce Thompson Institute, Ithaca, New York 14853
Plant Physiol. 2020 Nov;184(3):1263-1272. doi: 10.1104/pp.20.00997. Epub 2020 Sep 1.
Arbuscular mycorrhizal (AM) symbiosis is a mutually beneficial association of plants and fungi of the subphylum Glomeromycotina. Endosymbiotic AM fungi colonize the inner cortical cells of the roots, where they form branched hyphae called arbuscules that function in nutrient exchange with the plant. To support arbuscule development and subsequent bidirectional nutrient exchange, the root cortical cells undergo substantial transcriptional reprogramming. (), previously studied in several dicot plant species, is a major regulator of this cortical cell transcriptional program. Here, we generated mutants and overexpressors in a monocot, The AM phenotypes of two line revealed that is only partly required to enable arbuscule development in Transgenic lines constitutively overexpressing showed constitutive expression of AM-inducible genes even in the shoots. Following inoculation with AM fungi, -overexpressing plants showed higher arbuscule densities relative to controls, indicating the potential to manipulate the relative proportion of symbiotic interfaces via modulation of However, the overexpressors also show altered expression of hormone biosynthesis genes and aberrant growth patterns, including stunted bushy shoots and poor seed set. While these phenotypes possibly provide additional clues about the scope of influence of , they also indicate that directed approaches to increase the density of symbiotic interfaces will require a more focused, potentially cell type specific manipulation of transcription factor gene expression.
丛枝菌根 (AM) 共生是植物和 Glomeromycotina 亚门真菌之间互利共生的关系。内生 AM 真菌定殖于根的内皮层细胞，在那里它们形成分枝菌丝，称为丛枝，丛枝在与植物的营养交换中起作用。为了支持丛枝的发育和随后的双向营养交换，根皮层细胞经历了大量的转录重编程。（），以前在几种双子叶植物物种中进行了研究，是这个皮层细胞转录程序的主要调节剂。在这里，我们在单子叶植物中生成了 突变体和 过表达体，结果表明在 中， 仅部分需要使丛枝发育正常。转基因系中组成型过表达 ，即使在茎中也表现出 AM 诱导基因的组成型表达。用 AM 真菌接种后，与对照相比，过表达植物的丛枝密度更高，这表明通过调节 有可能操纵共生界面的相对比例。然而，过表达体也表现出激素生物合成基因的表达改变和异常的生长模式，包括矮化丛生的枝条和种子结实不良。虽然这些表型可能提供了关于 的影响范围的更多线索，但它们也表明，为了增加共生界面的密度，需要更有针对性地、可能是针对特定细胞类型的转录因子基因表达的操纵。
