ENHANCED GRAVITROPISM1 (EGT1), a Tubby-like F-box protein fi...

created [InstanceEdit:9916282] Naithani, Sushma, 2024-07-23
dbId 9916293
displayName ENHANCED GRAVITROPISM1 (EGT1), a Tubby-like F-box protein fi...
literatureReference
schemaClass Summation
text ENHANCED GRAVITROPISM1 (EGT1), a Tubby-like F-box protein first found in barley and wheat, plays a crucial role in controlling root angle in cereal crops through an antigravitropic mechanism (Fusi et al., 2022; PMID: 35881796). The rice ortholog of EGT1 is OsTLP8/Os02g0705300 / LOC_Os02g47640. The rice EGT1 ortholog has not been functionally characterized. In barley and wheat, EGT1 is shown to counteract the gravitropic machinery?s ability to bend the root and thereby controling root angle. A loss-of-function mutation in the barley HvEGT1 (HORVU6Hr1G068970) and in wheat TdEGT1 genes resulted in a root phenotype where every root class adopts a steeper angle (Fusi et al., 2022; PMID: 35881796). Specifically, the mutation in barley HvEGT1 gene was in the first intron of HORVU6Hr1G068970 resulted in a splice acceptor variant encoding a deletion of nine amino acids in HvEGT1 protein (without any frameshift). This mutation did not affect HORVU6Hr1G068970 transcription, thus, steeper root phenotype in the mutant was due to altered HvEGT1 protein structure or function (Fusi et al., 2022; PMID: 35881796). Furthermore, HvEGT1 is highly expressed in elongation zone and primarily in stele tissues, and cell walls in the elongation zone. Additionally, atomic force microscopy has revealed that the cell walls of elongating Hvegt1 root cortical cells are significantly less stiff than those of the wild-type. Thus, EGT1 plays a positive role in making cortical tissue of root elongation zone more stiff and regulates cell wall stiffening and loosening, counteracting the action of gravitropic mechanisms. EGT1 impedes bending of the root (Fusi et al., 2022; PMID: 35881796). It?s function is to promote horizontal spread of roots by promoting antigravitropic offset (AGO) mechanisms . EGT1 functions in a auxin-independent manner.