Benzoxazinoids (BXs) are important compounds in plant defense. Their allelopathic, nematode suppressive and antimicrobial properties are well known. BXs are found in monocot plants and in a few species of dicots. Over 50 years of study have led to the characterization of the chromosomal locations and coding sequences of almost all the genes involved in BX biosynthesis in a number of cereal species: ZmBx1-ZmBx10a7c in maize, TaBx1-TaBx5, TaGT and Taglu in wheat, ScBx17ScBx5, ScBx6-like, ScGT and Scglu in rye. So far, the ortholog of the maize Bx7 gene has not been identified in the other investigated species. This review aims to summarize the available data on the genetic basis of BXs biosynthesis in cereals.

Benzoxazinoids (BX) are major secondary metabolites of gramineous plants that play an important role in disease resistance and allelopathy. They also have many other unique properties including anti-bacterial and anti-fungal activity, and the ability to reduce alfa–amylase activity. The biosynthesis and modification of BX are controlled by the genes Bx1 ÷ Bx10, GT and glu, and the majority of these Bx genes have been mapped in maize, wheat and rye. However, the genetic basis of BX biosynthesis remains largely uncharacterized apart from some data from maize and wheat. The aim of this study was to isolate, sequence and characterize five genes (ScBx1, ScBx2, ScBx3, ScBx4 and ScBx5) encoding enzymes involved in the synthesis of DIBOA, an important defense compound of rye. Using a modified 3D procedure of BAC library screening, seven BAC clones containing all of the ScBx genes were isolated and sequenced. Bioinformatic analyses of the resulting contigs were used to examine the structure and other features of these genes, including their promoters, introns and 3’UTRs. Comparative analysis showed that the ScBx genes are similar to those of other Poaceae species, especially to the TaBx genes. The polymorphisms present both in the coding sequences and non-coding regions of ScBx in relation to other Bx genes are predicted to have an impact on the expression, structure and properties of the encoded proteins.Electronic supplementary materialThe online version of this article (doi:10.1007/s13353-015-0271-z) contains supplementary material, which is available to authorized users.

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