PHYSIOLOGICAL TRAITS OF ENDORNAVIRUS- INFECTED …...PHYSIOLOGICAL TRAITS OF ENDORNAVIRUS-INFECTED...
Transcript of PHYSIOLOGICAL TRAITS OF ENDORNAVIRUS- INFECTED …...PHYSIOLOGICAL TRAITS OF ENDORNAVIRUS-INFECTED...
PHYSIOLOGICAL TRAITS OF ENDORNAVIRUS-INFECTED AND ENDORNAVIRUS-FREE BELL
PEPPER
Cesar Escalante, Rodrigo A. Valverde
Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, Louisiana
Plant viruses
Acute: Disease causing viruses
Persistent: Do not cause disease
Tobacco mosaic virus
Bell pepper endornavirus
Persistent viruses Acute viruses
Do not cause detectable symptoms Cause symptoms and diseases
Bell pepper endornavirus Tobacco mosaic virus
Persistent viruses Acute viruses
Do not cause detectable symptoms
Do not move from cell-to-cell
Cause symptoms and diseases
Move from cell-to-cell and systemically
Bell pepper endornavirus Tobacco mosaic virus
Persistent viruses Acute viruses
Do not cause detectable symptoms
Do not move from cell-to-cell
Present in all host cells and tissues
Cause symptoms and diseases
Move from cell-to-cell and systemically
Not present in all host cells and tissues
Bell pepper endornavirus Tobacco mosaic virus
Persistent viruses Acute viruses
Do not cause detectable symptoms
Do not move from cell-to-cell
Present in all host cells and tissues
Transmitted only by seed (gametes)
Cause symptoms and diseases
Move from cell-to-cell and systemically
Not present in all host cells and tissues
Transmitted: mechanically, vectors, seed,
pollen, and grafting
Bell pepper endornavirus Tobacco mosaic virus
Persistent viruses ARE NOT transmitted:
Mechanically Graft Dodder Vectors
Transmitted only through the gametes:
80-100 % maternally (egg cell)
60-100 % paternally (pollen)
Transmission properties of persistent plant viruses
Persistent plant viruses:Endosymbionts present in all plant cells without causing
visible symptoms
Rice Bean Melon Pepper Avocado
14-17 kb linear ssRNA
Kb
15 –
5 -
1 -
Endornaviridae
Plants, fungi, oomycetes
Capsicum annuum(Solanaceae)
Pepper (bell)
Phaseolus vulgaris(Fabaceae)
Common bean
Cucumis melo(Cucurbitaceae)
Melon/Cantaloupe
Oryza sativa(Poaceae)
Rice
Persea americana(Lauraceae)
Avocado
Major crops infected by endornaviruses
Capsicum annuum(Solanaceae)
Pepper (bell)All cultivars tested
Phaseolus vulgaris(Fabaceae)
Common bean
Cucumis melo(Cucurbitaceae)
Melon/CantaloupeAll cultivars tested
Oryza sativa(Poaceae)
Rice
Persea americana(Lauraceae)
Avocado
Major crops infected by endornaviruses
Capsicum annuum C. annuum C. annuum C. annuum
Capsicum baccatum Capsicum frutescens Capsicum chinense
Capsicum annuum horticultural types, and other Capsicum species are infected with bell pepper
endornavirus (BPEV)
BPEV+ BPEV- BPEV+ BPEV+
Identification of a BPEV-free bell pepper
Marengo bell pepperMarengo bell pepper
Obtained after testing over 100 individual plants of bell pepper cv Marengo
Okada et al., 2013. J Gen Virol
Development of two Marengo bell peppernear-isogenic lines (NILs)
Escalante & Valverde, unpublished
BPEV + BPEV - Escalante & Valverde, unpublished
Near-isogenic lines of Marengo bell pepper
BPEV + BPEV -
BPEV+ BPEV- BPEV+ BPEV-
Escalante & Valverde, unpublished
Near-isogenic lines of Marengo bell pepper
Tomato spotted wilt virus
BPEV + BPEV - BPEV + BPEV -
Near-isogenic lines inoculated with tomato spotted wilt virus and potato virus Y
Potato virus Y
Escalante & Valverde, unpublished
Mock inoc. Mock inoc.
BPEV + BPEV - BPEV + BPEV -
Tobacco mosaic virus Pepper mild mottle virus
Escalante & Valverde, unpublished
Near-isogenic lines inoculated with tobacco mosaic virus and pepper mild mottle virus
Escalante & Valverde, unpublished
BPEV + BPEV-
Near-isogenic lines inoculated with tobacco mild green mosaic virus
BPEV +
BPEV-
Escalante & Valverde, unpublished
Near-isogenic lines inoculated with tobacco mild green mosaic virus
Plastic pots containing bell pepper near-isogenic linesplaced in a gravel plot
Escalante & Valverde, unpublished
Escalante & Valverde, unpublished
Seed germination
Number of fruits
2.4
2.5
2.6
2.7
2.8
2.9
3
BPEV- BPEV+
Tota
l Ch
loro
ph
yll (
mg/
g)a
a
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
BPEV- BPEV+
Car
ote
nio
ds
(mg)
aa
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
BPEV- BPEV+
An
tho
cyan
in (
Ab
s53
0/g
F.W
.)
a
a
A
B
C
Chlorophyll (A) Carotenoid (B) andAnthocyanin (C) content
Escalante & Valverde, unpublished
Heat map of the transcriptome of the two bell pepper NILs
Escalante et al., unpublished
BPEV- BPEV- BPEV+ BPEV+
Summary
There is no evidence that BPEV affect the plant phenotype
We found an association of BPEV with lower fruit yield and seed germination
BPEV is associated with inhibition of a systemic necrosis caused by TMGMV
We are currently, conducting bioinformatics analyses of RNAseq data on the two bell pepper near-isogenic lines
Plant endornaviruses: questions
Beneficial?
Detrimental?
Do they play an active role when the host is exposed to abiotic/abiotic stresses?
Why bell pepper and melon breeders without knowing of the presence of endornaviruses in those two crops appear to have selected only endornavirus-infected lines?
Future and ongoing endornavirus research
Develop a novel method for inoculation of endornaviruses
Generate near-isogenic lines of endornavirus-free and endornavirus-infected plants
Continue differential gene expression studies and validate and test selected genes
Interaction studies of endornaviruses with biotic (pathogens, herbivores) and abiotic agents (temperature, water, salt, etc.)
Investigate mechanisms of gene silencing/suppressor of gene silencing associated with endornavirus infections
RAV
Collaborators on bell pepper endornavirus research
Sejo Sabanadzovic Mississippi State University
Ryo OkadaTokyo University of Agriculture and Technology
Surasak Khankhum & Cesar EscalanteLouisiana State University
Marilyn RoossinckThe Pennsylvania State University
Noa Sela & Aviv DombrovskyThe Volcani Center, Israel
CSIC, Malaga Spain
USDA/NIFAUSDA-ARS, National Plant Germplasm System
US-Israel BARD feasibility grant