The role of DIMBOA in maize biotic stress resistance - presence of DIMBOA biosynthesis bx1 gene in NS inbred lines

Abstract

DIMBOA (2-4-dihidroksi-7-metoksi-1 4-benzoksazin-3-on) is a secondary metabolite in grasses which be- ongs to benzoxazinoid class of chemical compounds and have a protective role against bacteria, fungi, in- sects and other pests. It is present in many species of Poaceae family, including maize, wheat and rye. In maize this benzoxazinoid has proved to possess allelopathic activity and provide resistance against aphids (Rapalosiphum padi, R. maydis), corn borers (Ostrinia nubilalis, O. furnacalis, Sesamia nonagrioides, S. exigua, Diatraea grandiosella) and fungi (Diplodia maydis, Setosphaeria turcica). DIMBOA is formed only when plant tissues are damaged by interaction of benzoxazinoid glucosides from vacuoles with specific enzymes glucosidases re leased frorn plastids. The concentration of DIMBOA decreases during the vegetative growth and as plants mature, hence the greatest resistance against pests and diseases in early developmental phases. Biosynthesis of DIMBOA is regulated by nine bx genes (bx1-bx9), however, the polymorphism within bx7 has the largest ef fect of DIMBOA content. The dominant allele form of 6x7 gene provides plants with resistance against pest, whereas plants with the recessive allele are susceptible. To assess the presence and variability of bx gene in maize breeding material, a set of 96 divergent maize inbred lines developed at the Institute of Field and Vegetable Crops in Novi Sad was screened with a functional SSR marker. The fragment size of PCR products was obtained by capillary electrophoresis using Applied Biosystems 30130 Analyzer. The aim of the study was to identify the source of disease and pest resistance in early development phases of maize and examine the possibility of application of the microsatellite for selection of genotypes in maize breeding process Serbian Ministry of Education, Science and Technological Development 1231073.