Plant Signal Behav. 2013 Oct;8(10):doi: 10.4161/psb.26779. doi: 10.4161/psb.26779.
Three O-methyltransferases (BX10a, b, c) catalyze the conversion of 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one glucoside (DIM BOA-Glc) to 2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one glucoside (HDMBOA -Glc) in maize (Zea mays). Variation in benzoxazinoid accumulation and resistance to Rhopalosiphum maidis (corn leaf aphid) was attributed to a natural CACTA family transposon insertion that inactivates Bx10c. Whereas maize inbred line B73 has this transposon insertion, line CM L277 does not. To characterize the phenotypic effects of DIM BOA-Glc methyltransferase activity, we created near-isogenic lines derived from B73 and CM L277 that do or do not contain the transposon insertion. Bx10c inactivation causes high DIM BOA -Glc, low HDMBOA-Glc, and decreased aphid reproduction relative to near-isogenic lines that have a functional Bx10c gene. These results confirm the importance of this locus in maize aphid resistance. The availability of Bx10c near-isogenic lines will facilitate further research on the function of different benzoxazinoids and DIM BOA-Glc methyltransferase activity in maize defense against herbivores and pathogens.
三种 O-甲基转移酶（BX10a、b、c）催化 2,4-二羟基-7-甲氧基-1,4-苯并恶嗪-3-酮葡萄糖苷（DIM BOA-Glc）转化为 2-羟基-4,7-二甲氧基-1,4-苯并恶嗪-3-酮葡萄糖苷（HDMBOA-Glc），这一过程发生在玉米（Zea mays）中。苯并恶嗪类物质积累和对玉米叶蝉（Rhopalosiphum maidis）的抗性的变化归因于一个自然 CACTA 家族转座子插入，该插入使 Bx10c 失活。尽管玉米自交系 B73 具有该转座子插入，但系 CM L277 则没有。为了研究 DIM BOA-Glc 甲基转移酶活性的表型效应，我们从 B73 和 CM L277 中创建了近等基因系，这些系含有或不含有转座子插入。Bx10c 的失活导致 DIM BOA-Glc 含量升高，HDMBOA-Glc 含量降低，与具有功能性 Bx10c 基因的近等基因系相比，玉米叶蝉的繁殖能力下降。这些结果证实了该基因座在玉米抗叶蝉中的重要性。Bx10c 近等基因系的可用性将有助于进一步研究不同苯并恶嗪类物质和 DIM BOA-Glc 甲基转移酶活性在玉米防御草食动物和病原体中的功能。
