The branched spike phenotype is an important supernumerary spikelet trait of Triticum turgidum L. associated with the production of significantly more grains per spike, thereby offering a higher potential yield. However, the genetic basis of branch meristem (BM) development remains to be fully elucidated in wheat. TAW1, an ALOG (Arabidopsis LSH1 and Oryza G1) family gene, has been shown to function as a unique regulator in promoting BM development in rice. In this study, we found that the development pattern of the BMs of the branched spike in wheat was similar to the indeterminate BMs of rice. Moreover, phylogenetic analysis classified the ALOG genes into 12 groups. This family of genes was found to have evolved independently in eudicots and monocots and was evolutionarily conserved between wheat and rice as well as during wheat polyploidization. Furthermore, experiments revealed that TtALOG2-1A, a TAW1-homologous gene, plays a significant role in regulating the transition of indeterminate BM fate. Finally, large-scale RNA-sequencing studies and quantitative real-time polymerase chain reaction (qRT-PCR) experiments revealed that members of the TtALOGs may act upstream of the TtMADS22, TtMADS47, and TtMADS55 genes to promote indeterminate BM activities. Our findings further knowledge on BM development in wheat.

Fatty acyl-CoA reductase (FAR) is involved in the biosynthesis of primary alcohols, which are waxy constituents that play an important role in plant stress. Previous studies have shown that primary alcohol is the most important component in the wheat seeding stage and accounts for more than 80% of the total composition. To date, eight FAR genes have been identified in wheat, but there has not been a systematic analysis. In this study, a comprehensive overview of the TaFAR gene family was performed, including analyses of the phylogenetic relationship, the multiple sequence alignment, the conserved motif distribution and the expression pattern. The result showed that a total of 41 wheat FAR genes were identified and designated TaFAR1-A–TaFAR22-D; all FAR genes were divided into six classes according to their phylogenetic relationship, and most of the FAR genes might be related to wheat cuticular wax synthesis. The analysis of the promoter binding site showed that TaFAR genes could be regulated by the MYB transcription factor and could be used as target genes for hormone regulation under adverse conditions, especially during a drought. This study provides a basis for further analyses of the TaFAR gene function and of upstream regulatory genes.