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Gibberellin oxidases (GAoxs) identified from many species play indispensable roles in GA biosynthesis and GA signal transduction. However, there has been limited research conducted on the GAox family of Salix matsudana , a tetraploid ornamental tree species. Here, 54 GAox genes were identified from S. matsudana and renamed as SmGA20ox1–22 , SmGA2ox1–24 , SmGA3ox1–6 , and SmGAox-like1/2. Gene structure and conserved motif analysis showed that SmGA3ox members possess the 1 intron and other SmGAoxs contain 2–3 introns, and motif 1/2/7 universally present in all SmGAoxs. A total of 69 gene pairs were identified from SmGAox family members, and the Ka/Ks values indicated the SmGAoxs experience the purifying selection. The intra species collinearity analysis implied S. matsudana , S. purpurea , and Populus trichocarpa have the close genetic relationship. The GO analysis suggested SmGAoxs are dominantly involved in GA metabolic process, ion binding, and oxidoreductase activity. RNA-sequencing demonstrated that some SmGAox s may play an essential role in salt and submergence stresses. In addition, the SmGA20ox13/21 displayed the dominant vitality of GA20 oxidase, but the SmGA20ox13/21 still possessed low activities of GA2 and GA3 oxidases. This study can contribute to reveal the regulatory mechanism of salt and submergence tolerance in willow. • A total of 54 SmGAoxs were identified from the Salix matsudana genome. • SmGAoxs were involved in GA metabolic process, ion binding, and oxidoreductase activity. • The SmGA20ox13/21 displayed the dominant vitality of GA20 oxidase, but they still possessed low activities of GA2 and GA3 oxidases. [ABSTRACT FROM AUTHOR]

Plant non-specific lipid transfer proteins (nsLTPs) are small and have a broad biological function involved in reproductive development and abiotic stress resistance. Although a small part of plant nsLTPs have been identified, these proteins have not been characterized in poplar at the genomic level. A genome-wide characterization and expression identification of poplar nsLTP members were performed in this study. A total of 42 poplar nsLTP genes were identified from the poplar genome. A comprehensive analysis of poplar nsLTPs was conducted by a phylogenetic tree, duplication events, gene structures, and conserved motifs. The cis -elements of poplar nsLTPs were predicted to respond to light, hormone, and abiotic stress. Many transcription factors (TFs) were identified to interact with poplar nsLTP cis -elements. The tested poplar nsLTPs were expressed in leaves, stems, and roots, but their expression levels differed among tested tissues. Most poplar nsLTP expression levels were changed by abiotic stress, implying that poplar nsLTP may be involved in abiotic stress resistance. Network analysis showed that poplar nsLTPs are putative genes involved in fatty acid (FA) metabolism. This research provides sight into the further study to explain the regulatory mechanism of the poplar nsLTPs. [ABSTRACT FROM AUTHOR]