Phosphate Starvation Primes Plant Immunity through an ABA-OsbZIP12-Phytoalexin Signaling Network
Yuqing He1, Jitao Hu2, Li Jiang3
1State Key Laboratory for Quality and Safety of Agro - Products, Key Laboratory of Biotechnology in Plant Protection of MOA of China and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, P. R. China, Hangzhou, 310021; Key Laboratory of Traceability for Agricultural Genetically Modified Organisms, Ministry of Agriculture and Rural Affairs, P. R. China, Hangzhou, 310021.
Phosphate starvation boosts rice immunity to blast disease via a complex abscisic acid (ABA) signaling pathway. This involves the transcription factor OsbZIP12, enhancing phytoalexin sakuranetin accumulation and disease resistance.
Area of Science:
- Plant Science
- Molecular Plant Pathology
- Agricultural Science
Background:
- Phosphate (Pi) deficiency limits crop yields globally.
- The role of ABA in nutrient stress and plant immunity is not well understood.
- Rice blast, caused by Magnaporthe oryzae, is a devastating crop disease.
Purpose of the Study:
- To elucidate the molecular mechanisms linking Pi starvation, ABA signaling, and rice immunity.
- To identify key regulators in the Pi-ABA-immunity network.
- To explore strategies for enhancing crop disease resistance through nutritional management.
Main Methods:
- Physiological and molecular analyses of rice under Pi starvation.
- Quantification of ABA, phytoalexin sakuranetin (SAK), and disease resistance.
- Identification and functional characterization of transcription factors involved in the signaling pathway.
- Genetic analysis using knockout mutants.
Main Results:
- Pi-starved rice showed elevated ABA levels, increased SAK accumulation, and enhanced resistance to M. oryzae.
- ABA exhibited a biphasic effect on immunity, with sustained low levels promoting resistance.
- The transcription factor OsbZIP12 was identified as a central integrator, directly activating SAK biosynthesis (OsNOMT) and responding to both Pi and ABA signals.
- OsbZIP12 is crucial for SAK-dependent resistance.
Conclusions:
- A novel Pi-ABA-immunity signaling network orchestrated by OsbZIP12 is established in rice.
- This network links nutritional status to immune responses via ABA signaling and phytoalexin production.
- OsbZIP12 provides a molecular target for improving crop resilience by manipulating nutritional stress responses.
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