Benzoksazinoidi - zaštitni sekundarni metaboliti žitarica - biohemija i genetička kontrola

Sanja Mikić,Shakoor Ahmad

doi:10.5937/ratpov55-12210

Abstract

Benzoxazinoids (1,4-benzoxazin-3(4H)-one derivatives, BXs) are plant secondary metabolites that play a crucial role in plant resistance to insects, fungi, bacteria and nematodes, and in weed suppression during early plant life. These biochemicals are constitutive compounds found in some members of the family Poaceae and have been studied in detail in maize (Zea mays L.), wheat (Triticum aestivum L.) and rye (Secale cereale L.). The most effective allelopathic benzoxazinoids are 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA) and 2,4-dihydroxy-1,4-benzoxazin-3-one (DIBOA), classified as hydroxamic acids. Aiming to draw attention to the importance of BXs in plant defence and their potential application in cereal protection, this review summarises the recent findings in genetic control, biochemical pathways, and the mode of action of these secondary metabolites and addresses unresolved questions related to BXs.

Highlights

Benzoxazinoids (1,4-benzoxazin-3(4H)-one derivatives, BXs) are protective and allelopathic secondary metabolites that have antifungal, antibacterial, insecticidal, antifeedant and phytotoxic properties. They are found sporadically in several phylogenetically unrelated non-crop dicot species that belong to families Plantaginaceae, Ranunculaceae, Acanthaceae, Lamiaceae, and Scrophulariaceae (Dick et al, 2012)
The genetics of BXs biosynthesis will be presented on the example of maize, being the crop most studied for this topic, and compared to wheat and rye
The methoxy derivative DIMBOA is more frequent in maize and wheat, whereas DIBOA prevails in rye and wild barley (Hordeum lechleri (Steud.) Schenck) (Niemeyer, 2009)

Summary

Introduction

The genetics of BXs biosynthesis will be presented on the example of maize, being the crop most studied for this topic, and compared to wheat and rye. In addition to the Bx genes, two more genes, Glu1 and Glu2, on chromosome 10 were found to code for the plastid enzymes β-glucosidases that convert DIBOA -glucoside or DIMBOA-glucoside to their toxic aglucones (Babcock & Esen, 1994; Sue et al, 2011).

Results

Conclusion