First Report of Erysiphe necator Causing Powdery Mildew to Rubber Tree (Hevea brasiliensis) in Brazil

Powdery mildew causes substantial losses in crop and economic plant yields worldwide. Although powdery mildew infection of rubber trees (Hevea brasiliensis), caused by the biotrophic fungus Erysiphe quercicola, severely threatens natural rubber production, little is known regarding the mechanism by which E. quercicola adapts to H. brasiliensis to invade the host plant. In barley and Arabidopsis thaliana, lifeguard (LFG) proteins, which have topological similarity to BAX INHIBITOR-1, are involved in host plant susceptibility to powdery mildew infection. In this study, we characterized an H. brasiliensis LFG protein, HbLFG1, with a focus on its function in regulating defence against powdery mildew. HbLFG1 gene expression was found to be upregulated during E. quercicola infection. HbLFG1 showed conserved functions in cell death inhibition and membrane localization. Expression of HbLFG1 in Nicotiana benthamiana leaves and A. thaliana Col-0 was demonstrated to significantly suppress callose deposition induced by conserved pathogen-associated molecular patterns chitin and flg22. Furthermore, we found that overexpression of HbLFG1 in H. brasiliensis mesophyll protoplasts significantly suppressed the chitin-induced burst of reactive oxygen species. Although A. thaliana Col-0 and E. quercicola displayed an incompatible interaction, Col-0 transformants overexpressing HbLFG1 were shown to be susceptible to E. quercicola. Collectively, the findings of this study provide evidence that HbLFG1 acts as a negative regulator of plant immunity that facilitates E. quercicola infection in H. brasiliensis.

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Overwintering form of Erysiphe necator, the causal agent of grapevine powdery mildew in southern Syria

Journal of Plant Protection Research ◽

10.1515/jppr-2017-0017 ◽

2017 ◽

Vol 57 (2) ◽

pp. 129-135 ◽

Cited By ~ 1

Author(s):

Nujoud Alimad ◽

Walid Naffaa ◽

Fawaz Azmeh

Keyword(s):

Powdery Mildew ◽

Winter Season ◽

Causal Agent ◽

Bud Break ◽

Erysiphe Necator ◽

First Report ◽

Primary Inoculum ◽

Grapevine Powdery Mildew ◽

Histopathological Studies ◽

Grapevine Buds

AbstractThe main aims of this study were to determine the overwintering form and the primary inoculum ofErysiphe necator,the causal agent of grapevine powdery mildew in southern Syria. Eleven vineyards located at five different geographical sites were visited every week from March to November in 2014 and 2015. The results of field and histopathological studies showed thatE. necatorsurvived as mycelium in dormant grapevine buds during the winter season. The first flag shoots were observed shortly after bud break in spring. The number of flag shoots varied greatly according to vineyards, cultivars and years, being present on 27.4 to 61.9% of the grapevines in 2014, and on 5.2 to 40% of the grapevines in 2015. The percentage of flag shoots on the same grapevine also varied according to the year, cultivar and location. It was between 4.3 to 9.4% in 2014, and 2.1 to 3.6% in 2015. The disease was observed only on Balady and Black cultivars. Conidia were released from the second week of May to early September. The first conidia were trapped around mid-May, and the first secondary symptoms were observed on leaves from mid-May to early June according to the site. Chasmothecia were observed on leaves in 45.5% of the studied vineyards. The first observation of chasmothecia on leaves was in July, and their numbers varied greatly between vineyards and years. Chasmothecia were not detected on bark, nor were ascospores trapped at the beginning of the season. These results confirmed that the ascospores did not have any role in the initiation of spring infection. To the best of our knowledge, this is the first report of the overwintering form ofE. necatorin Syria.

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First Report of Powdery Mildew Caused by Erysiphe quercicola on Hevea brasiliensis in Viet Nam

Plant Disease ◽

10.1094/pdis-11-15-1294-pdn ◽

2016 ◽

Vol 100 (6) ◽

pp. 1239-1239 ◽

Cited By ~ 3

Author(s):

L. T. T. Tam ◽

H. V. Cuong ◽

N. M. Khue ◽

M. V. Tri ◽

H. M. Thanh ◽

...

Keyword(s):

Powdery Mildew ◽

Hevea Brasiliensis ◽

Viet Nam ◽

First Report ◽

Erysiphe Quercicola

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First Report of Bacillus pumilus Causing Trunk Bulges of Rubber Tree (Hevea brasiliensis) in Malaysia

Plant Disease ◽

10.1094/pdis-08-18-1409-pdn ◽

2019 ◽

Vol 103 (5) ◽

pp. 1016

Author(s):

S. Mazlan ◽

D. Zulperi ◽

A. Wahab ◽

N. M. Jaafar ◽

Z. Sulaiman ◽

...

Keyword(s):

Hevea Brasiliensis ◽

Bacillus Pumilus ◽

Rubber Tree ◽

First Report

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First Report of Phytophthora citrophthora Causing Leaf Fall of Para Rubber Tree (Hevea brasiliensis) in Thailand

Plant Disease ◽

10.1094/pdis-07-16-0973-pdn ◽

2017 ◽

Vol 101 (6) ◽

pp. 1057-1057 ◽

Cited By ~ 2

Author(s):

B. Laohasakul ◽

P. Boonyapipat ◽

P. Plodpai

Keyword(s):

Hevea Brasiliensis ◽

Rubber Tree ◽

Leaf Fall ◽

Phytophthora Citrophthora ◽

First Report

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Initiation and development of Erysiphe necator chasmothecia and their role in the epidemiology of grapevine powdery mildew in southern Syria

Acta Mycologica ◽

10.5586/am.1088 ◽

2016 ◽

Vol 51 (2) ◽

Cited By ~ 1

Author(s):

Nujoud Alimad ◽

Walid Naffaa ◽

Fawaz Azmeh

Keyword(s):

Powdery Mildew ◽

Microscopic Examination ◽

Fungal Disease ◽

Erysiphe Necator ◽

Initial Development ◽

First Report ◽

Primary Inoculum ◽

Grapevine Powdery Mildew ◽

Sudden Reduction

Powdery mildew caused by <em>Erysiphe necator</em> is the most important fungal disease of grapevine in southern Syria. The purpose of this study was to determine the development of chasmothecia and their role as a primary inoculum in spring. Leaves and/or branches were examined by a stereo binocular from July to December 2014 and 2015. The number of chasmothecia was estimated on both surfaces of the leaves, and their viability was estimated by microscopic examination. During 2 years of survey chasmothecia were detected in 45.5% of vineyards. The initial development of chasmothecia on infected leaves was observed in the second half of July. Their numbers increased from July to October, and the sudden reduction at the beginning of November was noted. Chasmothecia were formed on 38.7% of infected leaves, with 12.5%, 18.4%, and 7.5% on the upper, under and on both surfaces of infected leaves respectively. Chasmothecia were more frequent on the leaf under side (0.6 / leaf) than on the leaf upper side (0.4 / leaf), but their occurrence on both sides together was relatively low (0.2 / leaf), and their numbers were highly variable between vineyards and years. Microscopic examination showed that chasmothecia contained 1–5 (usually three) asci with 1–4 (usually three) ascospores in each asci, and 65.6% of chasmothecia were empty. Their viability decreased between December and February, with an average viability of 1.2% and 0.2% in March and April, respectively. Chasmothecia were not detected on bark and ascospores were not trapped at the beginning of the season. These results indicate that the ascospores have no or little role in the initiation of spring infection. To the best of our knowledge, this is the first report of <em>E. necator</em> chasmothecia development and their role in the initiating infection on grapevine in Syria.

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