Zeng Jiamei, Zhang Tongfang, Huangfu Jiayi, Li Ran, Lou Yonggen
State Key Laboratory of Rice Biology & Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China.
College of Food Science, Southwest University, Chongqing 400715, China.
Plants (Basel). 2021 Feb 26;10(3):442. doi: 10.3390/plants10030442.
Allene oxide synthase (AOS) is the second enzyme in the biosynthesis of the plant defensive hormone jasmonic acid (JA). In rice, there are two AOSs, OsAOS1 and OsAOS2. However, the role of these two AOS genes in herbivore-induced defenses in rice remains unidentified. We cloned the two rice AOS genes and observed that the transcript level of both and was enhanced by mechanical wounding, the infestation of the striped stem borer (SSB) () or brown planthopper (BPH) (), and treatment with JA; however, responded more rapidly to SSB infestation and JA treatment than did . The antisense expression of (as-) or (as-) decreased levels of SSB- or BPH-induced JA, which, in turn, reduced the production of SSB-induced trypsin protease inhibitor (TrypPI) and volatiles as well as the resistance of rice to SSB. In contrast, BPH preferred to feed and oviposit on wild-type (WT) plants over as- and as- plants. Moreover, the survival of BPH nymphs on as- or as- lines was significantly lower than on WT plants. The increased resistance of as- or as- plants to BPH correlated with higher levels of BPH-induced HO and SA. These results indicate that and are both involved in herbivore-induced JA biosynthesis and play a vital role in determining the resistance of rice to chewing and phloem-feeding herbivores.
丙二烯氧化物合酶（AOS）是植物防御激素茉莉酸（JA）生物合成过程中的第二种酶。在水稻中，有两种AOS，即OsAOS1和OsAOS2。然而，这两个AOS基因在水稻受食草动物诱导的防御反应中的作用仍不明确。我们克隆了这两个水稻AOS基因，发现机械损伤、二化螟（SSB）或褐飞虱（BPH）的侵害以及JA处理均可提高它们的转录水平；然而，相较于OsAOS2，OsAOS1对SSB侵害和JA处理的反应更为迅速。反义表达的OsAOS1（as - OsAOS1）或OsAOS2（as - OsAOS2）降低了SSB或BPH诱导的JA水平，进而减少了SSB诱导的胰蛋白酶蛋白酶抑制剂（TrypPI）和挥发物的产生以及水稻对SSB的抗性。相反，相较于as - OsAOS1和as - OsAOS2植株，BPH更喜欢在野生型（WT）植株上取食和产卵。此外，BPH若虫在as - OsAOS1或as - OsAOS2品系上的存活率显著低于在WT植株上的存活率。as - OsAOS1或as - OsAOS2植株对BPH抗性的增强与BPH诱导的HO和SA水平升高相关。这些结果表明，OsAOS1和OsAOS2均参与食草动物诱导的JA生物合成，并在决定水稻对咀嚼式和刺吸式食草动物的抗性方面发挥着至关重要的作用。
