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Abstract Study on the regulation of broad‐spectrum resistance is an active area in plant biology.RESISTANCE TO POWDERY MILDEW 8.1(RPW8.1) is one of a few broad‐spectrum resistance genes triggering the hypersensitive response (HR) to restrict multiple pathogenic infections. To address the question how RPW8.1 signaling is regulated, we performed a genetic screen and tried to identify mutations enhancing RPW8.1‐mediated HR. Here, we provided evidence to connect an annexin protein with RPW8.1‐mediated resistance inArabidopsisagainst powdery mildew. We isolated and characterizedArabidopsis b7‐6mutant. A point mutation inb7‐6at theAt5g12380locus resulted in an amino acid substitution in ANNEXIN 8 (AtANN8). Loss‐of‐function or RNA‐silencing ofAtANN8led to enhanced expression ofRPW8.1, RPW8.1‐dependent necrotic lesions in leaves, and defense against powdery mildew. Conversely, over‐expression ofAtANN8compromised RPW8.1‐mediated disease resistance and cell death. Interestingly, the mutation in AtANN8 enhanced RPW8.1‐triggered H2O2. In addition, mutation in AtANN8 led to hypersensitivity to salt stress. Together, our data indicate that AtANN8 is involved in multiple stress signaling pathways and negatively regulates RPW8.1‐mediated resistance against powdery mildew and cell death, thus linking ANNEXIN's function with plant immunity.
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Overexpression of two CDPKs from wild Chinese grapevine enhances powdery mildew resistance in Vitis vinifera and Arabidopsis
Summary Calcium‐dependent protein kinases (CDPKs) play vital roles in metabolic regulations and stimuli responses in plants. However, little is known about their function in grapevine.Here, we report thatVpCDPK9andVpCDPK13, two paralogousCDPKsfromVitis pseudoreticulataaccession Baihe‐35‐1, appear to positively regulate powdery mildew resistance. The transcription of them in leaves of ‘Baihe‐35‐1’ were differentially induced upon powdery mildew infection. Overexpression ofVpCDPK9‐YFPorVpCDPK13‐YFPin theV. viniferasusceptible cultivar Thompson Seedless resulted in enhanced resistance to powdery mildew (YFP, yellow fluorescent protein). This might be due to elevation of SA and ethylene production, and excess accumulation of H2O2and callose in penetrated epidermal cells and/or the mesophyll cells underneath.Ectopic expression ofVpCDPK9‐YFPin Arabidopsis resulted in varied degrees of reduced stature, pre‐mature senescence and enhanced powdery mildew resistance. However, these phenotypes were abolished inVpCDPK9‐YFPtransgenic lines impaired in SA signaling (pad4sid2) or ethylene signaling (ein2). Moreover, both of VpCDPK9 and VpCDPK13 were found to interact with and potentially phosphorylate VpMAPK3, VpMAPK6, VpACS1 and VpACS2in vivo(ACS, 1‐aminocyclopropane‐1‐carboxylic acid (ACC) synthase; MAPK, mitogen‐activated protein kinase).These results suggest thatVpCDPK9andVpCDPK13contribute to powdery mildew resistance via positively regulating SA and ethylene signaling in grapevine.
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- Award ID(s):
- 1901566
- PAR ID:
- 10451992
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- New Phytologist
- Volume:
- 230
- Issue:
- 5
- ISSN:
- 0028-646X
- Page Range / eLocation ID:
- p. 2029-2046
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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