Cytokinin Confers Brown Planthopper Resistance by Elevating Jasmonic Acid Pathway in Rice.

Area of Science:

• Plant Biology
• Molecular Plant Pathology
• Chemical Ecology

Background:

• Plants utilize hormone pathways for defense against insect pests.
• Cytokinin's (CK) role in plant-insect interactions is not well understood.
• Brown planthopper (BPH) is a major rice pest.

Purpose of the Study:

• To investigate the role of CKs in rice resistance to BPH.
• To elucidate the signaling pathways involved in CK-mediated plant defense.

Main Methods:

• Investigated BPH feeding effects on CK biosynthesis and signaling in rice.
• Applied exogenous CKs and generated cytokinin oxidase/dehydrogenase (OsCKX) knockout rice lines.
• Analyzed jasmonic acid (JA) levels and JA-responsive gene expression.
• Utilized JA-deficient mutant (og1) to assess JA-dependency.

Main Results:

• BPH feeding increased CK biosynthesis and signaling in rice.
• Exogenous CK application and increased endogenous CKs (OsCKX knockouts) enhanced rice resistance to BPH.
• CK treatment and OsCKX knockout elevated JA levels and JA-responsive gene expression.
• CK-induced BPH resistance was compromised in JA-deficient mutant og1.

Conclusions:

• Cytokinins (CKs) act as positive regulators in rice resistance against brown planthopper (BPH).
• CK-mediated BPH resistance is dependent on the jasmonic acid (JA) pathway.
• Findings provide evidence for a novel role of CK in insect resistance and offer insights for pest management.