Artificial elevation of glutathione contents in salicylic acid‐deficient tobacco (
            Nicotiana tabacum
            cv. Xanthi
            NahG
            ) reduces susceptibility to the powdery mildew pathogen
            Euoidium longipes

The powdery mildew resistance genes RPW8.1 and RPW8.2 from Arabidopsis differ from the other isolated plant resistance (R) genes in their predicted protein domains and their resistance spectrum. The two homologous RPW8 genes encode small proteins featuring a predicted amino-terminal transmembrane anchor domain and a coiled-coil domain and confer resistance to a broad spectrum of powdery mildews. Here, we show that Arabidopsis plants expressing the RPW8 genes have enhanced resistance to another biotrophic pathogen, Hyaloperonospora parasitica, raising the possibility that the RPW8 genes may function to enhance salicylic-acid-dependent basal defenses, rather than as powdery-mildew-specific R genes. When overexpressed from their native promoters, the RPW8 genes confer enhanced resistance to the Cauliflower mosaic virus, but render plants more susceptible to the necrotrophic fungal pathogens Alternaria and Botrytis spp. Furthermore, we show that the RPW8 proteins appear to be localized to the endomembrane system, overlapping with the endoplasmic reticulum–associated small GTPase SAR1, and accumulate to higher levels in response to application of exogenous salicylic acid, one of the signaling molecules of plant defense.

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WY7 is a newly identified promoter from the rubber powdery mildew pathogen that regulates exogenous gene expression in both monocots and dicots

PLoS ONE ◽

10.1371/journal.pone.0233911 ◽

2020 ◽

Vol 15 (6) ◽

pp. e0233911

Author(s):

Yi Wang ◽

Chen Wang ◽

Mamy Jayne Nelly Rajaofera ◽

Li Zhu ◽

Wenbo Liu ◽

...

Keyword(s):

Gene Expression ◽

Powdery Mildew ◽

Powdery Mildew Pathogen ◽

Exogenous Gene

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Potential Role of Photosynthesis in the Regulation of Reactive Oxygen Species and Defence Responses to Blumeria graminis f. sp. tritici in Wheat

International Journal of Molecular Sciences ◽

10.3390/ijms21165767 ◽

2020 ◽

Vol 21 (16) ◽

pp. 5767

Author(s):

Yuting Hu ◽

Shengfu Zhong ◽

Min Zhang ◽

Yinping Liang ◽

Guoshu Gong ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Salicylic Acid ◽

Powdery Mildew ◽

Reactive Oxygen ◽

Post Inoculation ◽

Oxygen Species ◽

Chlorophyll Fluorescence Parameters ◽

H2o2 Accumulation ◽

Pathogenesis Related ◽

Defence Responses

Photosynthesis is not only a primary generator of reactive oxygen species (ROS) but also a component of plant defence. To determine the relationships among photosynthesis, ROS, and defence responses to powdery mildew in wheat, we compared the responses of the Pm40-expressing wheat line L658 and its susceptible sister line L958 at 0, 6, 12, 24, 48, and 72 h post-inoculation (hpi) with powdery mildew via analyses of transcriptomes, cytology, antioxidant activities, photosynthesis, and chlorophyll fluorescence parameters. The results showed that H2O2 accumulation in L658 was significantly greater than that in L958 at 6 and 48 hpi, and the enzymes activity and transcripts expression of peroxidase and catalase were suppressed in L658 compared with L958. In addition, the inhibition of photosynthesis in L658 paralleled the global downregulation of photosynthesis-related genes. Furthermore, the expression of the salicylic acid-related genes non-expressor of pathogenesis related genes 1 (NPR1), pathogenesis-related 1 (PR1), and pathogenesis-related 5 (PR5) was upregulated, while the expression of jasmonic acid- and ethylene-related genes was inhibited in L658 compared with L958. In conclusion, the downregulation of photosynthesis-related genes likely led to a decline in photosynthesis, which may be combined with the inhibition of peroxidase (POD) and catalase (CAT) to generate two stages of H2O2 accumulation. The high level of H2O2, salicylic acid and PR1 and PR5 in L658 possible initiated the hypersensitive response.

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