Search

Cuticular wax is a type of lipid covering the surface of plants, which is directly related to crop stress resistance. Thus, it is important to study wax-related genes and their regulatory mechanism in wax biosynthesis pathway for improving stress resistance. In this study, a wax-deficient barley mutant barley cuticular wax1(bcw1)was identified, and genetic analysis indicated that the trait was controlled by a single recessive nuclear gene. Phenotype observations showed that the tubule-shaped waxy crystals covering the sheath and stem epidermis of mutants disappeared, but there were no significant differences were detected in the leaf epidermis between mutant and wild type. Water loss results confirmed that the cuticular waxes and cutins improved water-holding capacity of plant. By combining the bulk segregant analysis (BSA) and specific locus amplified fragment sequencing (SLAF-seq) strategy, the wax-related gene BCW1 was located on chromosome 2H with a total length of 15.10 Mb. No cuticular wax-related genes have been reported in the 9 regions, indicating that BCW1 is a novel gene that plays roles in cuticular wax biosynthesis and wax crystals formation.

β-Ketoacyl CoA synthetase (KCS) is a key rate-limiting enzyme for the synthesis of very-long-chain fatty acids (VLCFAs) in plants that determines the synthesis rate and carbon chain length of VLCFAs, ultimately affecting the stress resistance of epidermal wax. In this study, a genome-wide characterization of the KCS family was conducted using high-quality barley (Hordeum vulgare L.) genome sequences. In total, 33 KCS genes were identified and were unevenly distributed in the distal centromere region of each chromosome. These genes were divided 12 subgroups based on sequence alignment and phylogenetic analysis, with members of the same subgroup possessing similar genes and motif structures. Expression analysis showed that the KCS genes demonstrate diverse tissue expression patterns in barley and also have overlapping functions. The barley KCS gene family also exhibited different response characteristics under drought stress. These results provide insights into the evolutionary processes and potential functions of the KCS gene family, offering a theoretical reference for studies on the physiological and biochemical regulation of KCS genes during barley growth and development, as well as for the genetic breeding analysis of wheat crops.

The SQUAMOSA PROMOTER BINDING PROTEIN box (SBP-box) gene family is a unique family of transcription factors in plants, which is found widely in green plants. This family functions involve many aspects of crop genetic improvement, such as yield, floral period, and stress resistances; therefore, it has an important practical application value. In this study, 14 non-redundant SBP-box genes were identified and isolated in barley (Hordeum vulgare L.) using Hordeum vulgare.IBSC_v2 in combination with bioinformatics analysis. The results revealed that 13 of these genes were unevenly distributed on five chromosomes, and another gene has not been anchored yet. Sequence alignments demonstrated that each SBP protein has highly conserved functional elements (zinc finger structure and nuclear localization signal sequence). Gene structure analysis indicated their diversified exon-introns structure. Phylogenetic analysis was used to classify the barley SBP-box genes into five subfamilies (D–H). Each subfamily was found to contain similar protein motifs and gene structures. Expression profiles based on the barley RNA-seq database found that the barley SBP-box gene family expresses the highest amount in the inflorescence and showed different expression patterns in different tissues and different stages. Overall, the results indicated that the barley SBP-box gene family is relatively conserved in evolution and function, and plays a crucial role in many stages of barley plant growth development. Our results provide a theoretical reference for subsequent studies of molecular regulation and genetic breeding of SBP-box family genes in barley growth and development.