Dendrocalamus farinosus SAUR36 is involved in growth regulation and drought tolerance

Abstract

Screening and identifying genes regulating rapid growth and drought adaptation in bamboo provides a theoretical basis for understanding the underlying mechanisms and is essential for sustainable utilization and elite germplasm breeding. Dendrocalamus farinosus is an important economic bamboo species due to its rapid growth and drought resistance. Small Auxin-Up RNAs (SAURs) are essential for regulating plant growth and abiotic stress adaptation. Here, a novel SAUR gene, designated DfSAUR36 , was identified and characterized from D. farinosus through transcriptome sequencing. DfSAUR36 was strongly induced by exogenous auxin stimulation and steadily up-regulated under drought stress, as revealed by the transcriptome expression matrix. Phylogenetic analysis showed that DfSAUR36 was a homolog of OsSAUR36, TaSAUR36, and PheSAUR34. Analysis of cis-elements in the DfSAUR36 promoter revealed numerous cis -regulatory elements associated with abiotic stress responses. The expression level of DfSAUR36 was significantly up-regulated in D. farinosus seedlings after 36 h of drought treatment. The function of DfSAUR36 was then verified in Arabidopsis . DfSAUR36 displayed a higher expression level in 100 cm bamboo shoots, and its protein was localized to the nucleus. Compared with Wild-type (WT), overexpression of DfSAUR36 in Arabidopsis resulted in transgenic plants with increased plant height and silique length, larger rosette leaves and flowers, higher fructose content in flowers, and enhanced drought tolerance. Under drought stress, the ratio of root biomass to aboveground biomass and the transcript levels of the drought-responsive genes AtRD29B and AtSOS1 were significantly higher in DfSAUR36 -overexpressing lines than in WT. Our findings not only reveal the biological function of DfSAUR36 in growth development and drought tolerance but also provide a promising candidate gene for molecular breeding aimed at improving growth vigor and drought resistance in D. farinosus and other economic crops.