Identification of Dof transcription factors in ramie (Boehmeria nivea L. Gaud) and their expression in response to different nitrogen treatments.

19 DNA binding with one finger (Dof) transcription factor genes were identified from genome and transcriptome data of ramie (Boehmeria nivea L. Gaud). Chemical character, subnuclear localization, motif analysis, phylogenetic analysis, and tissue-specific analysis were performed. To select BnDof genes participating in nitrogen metabolism, we analyzed the expression patterns of BnDof genes in different nitrogen conditions (N0, N4, N8, and N12) in different tissues. As a result, eight BnDof genes were identified. BnDof07 (stem) and BnDof14 (root) had higher expression levels in N0 and N4, and BnDof15 (stem and leaves) and BnDof18 (stem) both exhibited the highest expression level in N0, suggesting that these four genes may take part in nitrogen stress. In the leaves, BnDof01, BnDof06, BnDof09, and BnDof19 expression levels were higher in N8 and N12 but lower in N0 and N4. The present findings provide insights into nitrogen metabolism in ramie highlighting the need to investigate this aspect in further detail in future studies.

Discovery of Consistent QTLs of Wheat Spike-Related Traits under Nitrogen Treatment at Different Development Stages.

Spike-related traits such as spike length (Sl), fertile spikelet number (Fsn), sterile spikelet number (Ssn), grain number per spike (Gns), and thousand-kernel weight (Tkw) are important factors influencing wheat yield. However, reliably stable markers that can be used for molecular breeding in different environments have not yet been identified. In this study, a double haploid (DH) population was used for quantitative trait locus (QTL) mapping of five spike-related traits under four different nitrogen (N) supply dates in two locations and years. Seventy additive QTLs with phenotypic variation ranging from 4.12 to 34.74% and 10 major epistatic QTLs were identified. Eight important chromosomal regions on five chromosomes (1B, 2B, 2D, 5D, and 6A) were found. Sixteen stable QTLs were detected for which N application had little effect. Among those stable QTLs, QSl.sdau-2D-1, and QSl.sdau-2D-2, with phenotypic variation explained (PVE) of 10.4 and 24.2%, respectively, were flanked by markers Xwmc112 and Xcfd53 in the same order. The QTLs QSsn.sdau-2B-1, QFsn.sdau-2B-1, and QGns.sdau-2B, with PVE ranging from 4.37 to 28.43%, collocated in the Xwmc179-Xbarc373 marker interval. The consistent kernel wheat QTL (QTkw.sdau-6A) on the long arm of chromosome 6A, flanked by SSR markers Xbarc1055 and Xwmc553, showed PVE of 5.87-15.18%. Among these stable QTLs, the two flanking markers Xwmc112 and Xcfd53 have been validated using different varieties and populations for selecting Sl. Therefore, these results will be of great value for marker-assisted selection (MAS) in breeding programs and will accelerate the understanding of the genetic relationships among spike-related traits at the molecular level.