商品化杂交玉米先玉335、郑单958和京科968抗虫能力的比较研究
为探究我国商品化玉米品系对主要害虫抗性的差异，以先玉335、郑单958、京科968为材料，以亚洲玉米螟（Ostrinia furnacalis）、粘虫（Mythimna separata）和禾谷缢管蚜（Rhopalosiphum padi）为供试昆虫，探究了上述玉米品系喇叭口期对亚洲玉米螟和粘虫及抽雄期对蚜虫抗性差异，并测定了其主要抗虫化合物丁布类物质的含量。结果发现，京科968对玉米螟及禾谷缢管蚜抗性均高于另外两品系，对粘虫的抗性，郑单958和京科968高于先玉335。与之对应的是，喇叭口期京科968中丁布类物质含量最高，而抽雄期郑单958和京科968中丁布含量均高于先玉335。上述组织中丁布合成相关基因在郑单958及京科968中的表达量，也均高于先玉335。本研究揭示了杂交玉米抗虫性与抗性相关化合物含量及其相关基因表达间的正向相关关系，也为商品化抗虫玉米品系培育提供理论参考。
英文摘要:
To investigate the resistance of certain Chinese commercial hybrid maize lines to major herbivory, we assessed commercial maize lines Xianyu335, Zhengdan 958, and Jingke968 resistance to Ostrinia furnacalis and Mythimna separata at the mid-whorl -stage, and resistance to Rhopalosiphum padi at the tasseling-stage. The major defense-related secondary metabolites – benzoxazinoids (Bxs) were quantified. We found that Jingke968 was more resistant to O. furnacalis and R. padi herbivory than were the other two maize lines, while Zhengdan958 and Jingke968 showed higher levels of resistance to M. separata herbivory than did Xianyu335. Accordingly, leaves of Jingke968 had higher levels of Bxs at the mid-whorl stage than did the other two maize lines. Levels of Bxs in the leaves and stems of Zhengdan958 and Jingke968 at the tasseling stage were higher than those in Xianyu335. The levels of transcripts from Bx biosynthesis-related genes in Zhengdan958 and Jingke968 were higher than those in Xianyu335. This study reveals a positive correlation between resistance of maize to herbivory and defensive secondary metabolites as well as levels of transcripts from the corresponding biosynthesis-related genes, providing a reference for the breeding of herbivore-resistant commercial maize lines.
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