A large percentage of crop loss is due to insect damage, especially caterpillar damage. Plant chitinases are considered excellent candidates to combat these insects since they can degrade chitin in peritrophic matrix (PM), an important protective structure in caterpillar midgut. Compared to chemical insecticides, chitinases could improve host plant resistance and be both economically and environmentally advantageous. The focus of this research was to find chitinase candidates that could improve plant resistance by effectively limiting caterpillar damage. Five classes of endochitinase (I-V) genes were characterized in the maize genome, and we isolated and cloned four chitinase genes (chitinase A, chitinase B, chitinase I, and PRm3) present in two maize (Zea mays L.) inbred lines Mp708 and Tx601, with different levels of resistance to caterpillar pests. We also investigated the expression of these maize chitinases in response to fall armyworm (Spodoptera frugiperda, FAW) attack. The results indicated that both chitinase transcript abundance and enzymatic activity increased in response to FAW feeding and mechanical wounding. Furthermore, chitinases retained activity inside the caterpillar midgut and enzymatic activity was detected in the food bolus and frass. When examined under scanning electron microscopy, PMs from Tx601-fed caterpillars showed structural damage when compared to diet controls. Analysis of chitinase transcript abundance after caterpillar feeding and proteomic analysis of maize leaf trichomes in the two inbreds implicated chitinase PRm3 found in Tx601 as a potential insecticidal protein.

很大比例的作物损失是由于虫害，尤其是毛虫的损害。植物几丁质酶被认为是对抗这些昆虫的极好候选者，因为它们可以降解围养基质 (PM) 中的几丁质，这是毛虫中肠的重要保护结构。与化学杀虫剂相比，几丁质酶可以提高寄主植物的抗性，在经济和环境上都具有优势。这项研究的重点是寻找可以通过有效限制毛虫损伤来提高植物抗性的几丁质酶候选物。在玉米基因组中表征了五类内切几丁质酶 (IV) 基因，我们分离并克隆了两种玉米 ( Zea mays ) 中存在的四种几丁质酶基因（几丁质酶 A、几丁质酶 B、几丁质酶 I 和 PRm3）。L.) 近交系 Mp708 和 Tx601，对毛虫害虫具有不同程度的抗性。我们还研究了这些玉米几丁质酶对秋粘虫（草地夜蛾）的表达，一汽）攻击。结果表明，几丁质酶转录本丰度和酶活性都随着秋粘虫喂养和机械伤害而增加。此外，几丁质酶在毛虫中肠内保持活性，在食物丸和碎屑中检测到酶活性。在扫描电子显微镜下检查时，与饮食控制相比，来自 Tx601 喂养的毛虫的 PM 显示出结构损伤。毛虫喂养后几丁质酶转录本丰度的分析和两个近交系中玉米叶毛状体的蛋白质组学分析表明 Tx601 中发现的几丁质酶 PRm3 是一种潜在的杀虫蛋白。