GhSCL4 Acts as a Positive Regulator in Both Transgenic Arabidopsis and Cotton during Salt Stress

GRAS transcription factors play important roles in plant abiotic stress response,but their characteristics and functions in cotton have not been fully investigated.A cotton SCL4/7 subgroup gene in the GRAS family,GhSCL4,was found to be induced by NaCl treatments.Nuclear localization and transactivation activity of GhSCL4 indicate its potential role in transcriptional regulation.Transgenic Arabidopsis thaliana over-expressing GhSCL4 showed enhanced resistance to salt and osmotic stress.What’s more,the transcript levels of salt stress-induced genes(AtNHX1 and AtSOS1)and oxidation-related genes(AtAPX3 and AtCSD2)were more highly induced in the GhSCL4 over-expression lines than in wild type after salt treatment.Furthermore,silencing of GhSCL4 resulted in reduced salt tolerance in cotton caused by reactive oxygen species(ROS)enrichment under salt treatment,and antioxidant enzyme activities were accordingly significantly reduced in GhSLC4-silenced lines.These results indicated that GhSCL4 enhances salt tolerance of cotton by detoxifying ROS.In addition,the transient expression assay confirmed an interactive relationship between GhSCL4 and GhCaM7,which indicated that salt tolerance conferred by GhSCL4 might be associated with salt-induced Ca^(2+)/CaM7-mediated signaling.Taken together,GhSCL4 acts as a positive regulator in cotton during salt stress that is potentially useful for engineering salt-tolerant cotton.

TaACTIN7-D regulates plant height and grain shape in bread wheat

Exploitation of new gene resources and genetic networks contributing to the control of crop yield-related traits,such as plant height,grain size,and shape,may enable us to breed modern high-yielding wheat varieties through molecular methods.In this study,via ethylmethanesulfonate mutagenesis,we identify a wheat mutant plant,mu-597,that shows semi-dwarf plant architecture and round grain shape.Through bulked segregant RNA-seq and map-based cloning,the causal gene for the semi-dwarf phenotype of mu-597 is located.We find that a single-base mutation in the coding region of TaACTIN7-D(TaACT7-D),leading to a Gly-to-Ser(G65S)amino acid mutation at the 65th residue of the deduced TaACT7-D protein,can explain the semi-dwarfism and round grain shape of mu-597.Further evidence shows that the G65S mutation in TaACT7-D hinders the polymerization of actin from monomeric(G-actin)to filamentous(F-actin)status while attenuates wheat responses to multiple phytohormones,including brassinosteroids,auxin,and gibberellin.Together,these findings not only define a new semi-dwarfing gene resource that can be potentially used to design plant height and grain shape of bread wheat but also establish a direct link between actin structure modulation and phytohormone signal transduction.