The Roles of Phytohormones in Plant Defense Mechanisms Against the Brown Planthopper

Abstract

The brown planthopper (BPH; Nilaparvata lugens Stål) is the most significant insect pest compromising rice production globally. Phytohormones, which are small organic compounds produced by plants, play a crucial role in regulating plant growth and development. Nevertheless, extensive research has established that phytohormones are essential in modulating plant defense against BPH. Plants can achieve equilibrium between growth and defense by utilizing the intricate network of phytohormone signaling pathways to initiate optimal and efficient defensive responses to insects. In this review, we primarily address the roles of phytohormones in conferring resistance against BPH, with a focus on hormone cross-talk. We also discuss the potential value of integrating hormones with other agricultural practices to enhance plant defense and agricultural yield, which highlights the significance of novel approaches for environment-friendly insect pest management.

Keywords: BPH; plant hormone; resistance; rice; stress.

Figure 1

Schematic presentation of potentially conserved hormone cross-talks in resistance to BPH. JA, jasmonic acid; SA, salicylic acid; ABA, abscisic acid; GA, gibberellin; IAA, indole acetic acid; ET, ethylene; BR, brassinosteroid; CK, cytokinin; LOX, lipoxygenase; AOS, allene oxide synthase; COI1, coronatine-insensitive 1; JAZ, JA ZIM-domain; NOMT, naringenin 7-O-methyltransferase; OsCslF6, cellulose synthase-like F6; MLG, mixed-linkage β-1,3;1,4-D-glucans; PAL, phenylalanine ammonium lyase; ICS1, isochorismate synthase 1; 5HT, 5-hydroxytryptamine; NahG, salicylate hydroxylase; GID1, gibberellin-insensitive dwarf 1; GA2ox3, GA 2-oxidase 3; GA2ox7, GA 2-oxidase 7; PIF, phytochrome-interacting factor; TIR1, transport inhibitor response 1; AFB, auxin-signaling F-box; Aux/IAA, auxin/IAA; OsEIL1, ethylene-insensitive 3-like 1; EIN2, ethylene-insensitive 3; OsEBF1, EIN3-binding F-box 1; CKX, cytokinin oxidase/dehydrogenase.