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SQUAMOSA PROMOTER BINDING PROTEIN-box (SBP-box) family genes encoding plant-specific transcription factors are involved in many aspects of crop genetic improvement such as yield, plant-type and stress-resistance. The SBP-box gene family have important practical applications. In this study, 18 SBP-box genes were identified from the reference genome of sorghum (Sorghum bicolor L.) using bioinformatics. These genes distributed on nine chromosomes while eight of them located in the segmental duplication region. Phylogenetic reconstruction resulted in six subfamilies of SBP-box genes, among which SbSBP12, SbSBP3 and SbSBP15 are orthologous to ZmLG1, ZmTGA1 and ZmUB2/3 in corn, respectively. RNA-seq data analysis indicated that SbSBP-box genes show the highest expression level in primordial inflorescences. Moreover, SbSBP9 and SbSBP17 exhibited a tissue specific expression in primordial inflorescences. The expression levels of SbSBP5, SbSBP8 and SbSBP18 were increased in response to exogenous ABA and PEG,indicating that SbSBP-box genes are involved in the defense response against abiotic stresses in sorghum. This research provides references for cloning important genes in SbSBP-box gene family. Genes identified in this study could be considered as candidate genes for genetic improvement of sorghum.

Sterol methyltransferase 1 (STE1) catalyzes ∆7 sterol C-5 desaturation in the conversion of 24-methylenecholesterol to campestral in brassinosteroid (BR) biosynthesis, and STE1 has been proven to influence plant architecture by controlling the BR levels in Arabidopsis. In the present study, TaSTE (wheat), the ortholog of AtSTE1 (Arabidopsis), was cloned and mapped to wheat chromosome homologous group 3 in the interval between simple sequence repeats (SSRs) markers CWM48.1 and WMC532, with genetic distances of 17.7 and 7.6 cM, respectively. Both linkage and association analyses revealed that TaSTE-A1 was significantly associated with plant height in bread wheat. In silico expression results showed similar expression patterns among TaSTE, HvSTE1 (barley), OsSTE1 (also known as OsDWF7 in rice), and AtSTE1, suggesting that these orthologs might share common functions among wheat, barley, rice, and Arabidopsis. The haplotype frequencies in wild species, landraces, and modern cultivars indicated that haplotype II (Hap II) was associated with reduced plant height and positively selected during modern breeding improvement. One pair of complementary allele-specific polymerase chain reaction (PCR) markers can distinguish haplotype I (Hap I) and Hap II and could be developed to assist selection in wheat architecture breeding.