| Title: | "Natural variation in maize aphid resistance is associated with 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one glucoside methyltransferase activity" |
| Author(s): | Meihls LN; Handrick V; Glauser G; Barbier H; Kaur H; Haribal MM; Lipka AE; Gershenzon J; Buckler ES; Erb M; Kollner TG; Jander G; |
| Address: | "Boyce Thompson Institute for Plant Research, Ithaca, New York 14853, USA" |
| ISSN/ISBN: | 1532-298X (Electronic) 1040-4651 (Print) 1040-4651 (Linking) |
| Abstract: | "Plants differ greatly in their susceptibility to insect herbivory, suggesting both local adaptation and resistance tradeoffs. We used maize (Zea mays) recombinant inbred lines to map a quantitative trait locus (QTL) for the maize leaf aphid (Rhopalosiphum maidis) susceptibility to maize Chromosome 1. Phytochemical analysis revealed that the same locus was also associated with high levels of 2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one glucoside (HDMBOA-Glc) and low levels of 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one glucoside (DIMBOA-Glc). In vitro enzyme assays with candidate genes from the region of the QTL identified three O-methyltransferases (Bx10a-c) that convert DIMBOA-Glc to HDMBOA-Glc. Variation in HDMBOA-Glc production was attributed to a natural CACTA family transposon insertion that inactivates Bx10c in maize lines with low HDMBOA-Glc accumulation. When tested with a population of 26 diverse maize inbred lines, R. maidis produced more progeny on those with high HDMBOA-Glc and low DIMBOA-Glc. Although HDMBOA-Glc was more toxic to R. maidis than DIMBOA-Glc in vitro, BX10c activity and the resulting decline of DIMBOA-Glc upon methylation to HDMBOA-Glc were associated with reduced callose deposition as an aphid defense response in vivo. Thus, a natural transposon insertion appears to mediate an ecologically relevant trade-off between the direct toxicity and defense-inducing properties of maize benzoxazinoids" |
| Keywords: | "Amino Acid Sequence Animals Aphids/*physiology Benzoxazines/*metabolism Chromosome Mapping Chromosomes, Plant/genetics DNA Transposable Elements/genetics Disease Resistance/genetics Glucosides/metabolism Host-Parasite Interactions Isoenzymes/classificatio;" |
| Notes: | "MedlineMeihls, Lisa N Handrick, Vinzenz Glauser, Gaetan Barbier, Hugues Kaur, Harleen Haribal, Meena M Lipka, Alexander E Gershenzon, Jonathan Buckler, Edward S Erb, Matthias Kollner, Tobias G Jander, Georg eng Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. England 2013/07/31 Plant Cell. 2013 Jun; 25(6):2341-55. doi: 10.1105/tpc.113.112409. Epub 2013 Jun 28" |
