A Gibberellin Signaling-related Gene OsGID1Regulates Rice Resistance To The Brown Planthopper Nilaparvata Luqens

Gibberellin (Gibberellins, GAs), a kind of important tetracyclic double terpenoids functioning as plant hormones, plays a significant role in different aspects of plant growth and development. Moreover, it has been reported that GA-mediated plant growth inhibits the plant defense and vice versa, suggesting a trade-off between plant growth and defense. However, how GA signaling mediates herbivore-induced plant defense remains largely unknown. Here we cloned the receptor gene of GAs from rice, which is designated as OsGIDl. Transcriptional analysis showed that expression of OsGID1was induced by mechanical wounding, infestation of Niaparvata lugens (rice brown planthopper, BPH) and treatment with salicylic acid (SA) but not JA. Overexpression of OsGID1decreased the elicited levels of SA, but enhanced the ethylene level. In addition, OsGIDl negatively mediated the transcript levels of GA biosynthesis genes, such as OsCPS, OsKAO and OsGA20ox, whereas positively regulated the mRNA levels of DELLA, a repressor of GA signaling pathway. Bioassay showed that overexpression of OsGID1enhanced the resistance of rice to BPH:BPH female adults preferred to feed and oviposite on WT plants over on overexpression lines; moreover, female adults that fed on overexpression lines lay less eggs, compared to those who fed on WT plants. Our results suggest that OsGIDl plays an important role in herbivore-induced rice defense responses by regulating GA, SA, ethylene pathways.