scholarly journals IImproved Indexing of Citrus Viroids

Author(s):  
N. Duran-Vila ◽  
J. A. Pina ◽  
L. Navarro
Keyword(s):  
2006 ◽  
Vol 96 (4) ◽  
pp. 356-368 ◽  
Author(s):  
C. Vernière ◽  
X. Perrier ◽  
C. Dubois ◽  
A. Dubois ◽  
L. Botella ◽  
...  

Citrus exocortis viroid (CEVd), Citrus bent leaf viroid (CBLVd), a noncachexia variant of Hop stunt viroid (HSVd), Citrus viroid III (CVd-III), and Citrus viroid IV (CVd-IV) were co-inoculated as two-, three-, four-, and five-viroid mixtures to Clementine trees grafted on trifoliate orange to evaluate their effect on symptom expression, tree growth, and fruit yield. Most trees infected with CEVd-containing viroid mixtures developed exocortis scaling symptoms, as did CEVd alone, whereas most trees infected with HSVd- or CVd-IV-containing mixtures developed bark-cracking symptoms. Trees infected with mixtures containing both CEVd and CVd-IV revealed the existence of antagonism between these two viroids in terms of the expected bark-scaling and cracking symptoms. Synergistic interactions also were identified in trees infected with certain viroid combinations that, in spite of lacking CEVd, expressed exocortis-like scaling symptoms. Viroid interactions also affected the expected response of trees in terms of vegetative growth and fruit yield. Trees infected with viroid combinations containing CEVd or CVd-III were smaller and produced less fruit than trees infected with mixtures not containing these viroids. Viroid interactions on scion circumference and cumulative fruit yield, in terms of additivity of their effects, were statistically confirmed using a factorial analysis of variance model with two mean estimation approaches. In single-viroid infections, CEVd, CVd-III, and, to a lesser extent, CBLVd consistently and significantly reduced tree size and fruit yield. Conversely, HSVd and CVd-IV slightly increased fruit yield and reduced scion circumference. Rare and not consistent significant interactions were detected with the five-, four-, and three-viroid combinations. Antagonistic interactions between CEVd and CVd-III or CBLVd and CVd-III were revealed over the years with consistent significance. The antagonistic interaction between CEVd and CVd-IV was highly significant over the years when additional viroids were present; however, this antagonism appeared much later in the case of an exclusive interaction. HSVd and CVd-IV showed a consistent and significant synergistic interaction on yield only when both viroids were exclusively present. These results demonstrate antagonistic or synergistic relationships between citrus viroids depending on the viroid mixtures present in the host.


Author(s):  
M. Tessitori ◽  
R. La Rosa ◽  
G. Albanese ◽  
A. Catara

2006 ◽  
Vol 29 (4) ◽  
pp. 705-710 ◽  
Author(s):  
Amine Elleuch ◽  
Fattouma Djilani Khouaja ◽  
Imen Hamdi ◽  
Nabiha Bsais ◽  
Jean-Pierre Perreault ◽  
...  

Author(s):  
S. M. Garnsey ◽  
D. L. Zies ◽  
M. Irey ◽  
P. J. Sieburth ◽  
JS S. Semancik ◽  
...  

Author(s):  
Salvatore Davino ◽  
M. Davino ◽  
A. Caruso ◽  
G. Sorrentino ◽  
M. Guardo ◽  
...  
Keyword(s):  

Plant Disease ◽  
2007 ◽  
Vol 91 (9) ◽  
pp. 1205-1205 ◽  
Author(s):  
S. Rizza ◽  
A. Catara ◽  
X. F. Ma ◽  
Z. Deng

Citrus cultivation in China has increased since the late 1970s, with China now having the largest area of citrus in culture in the world that is spread in 22 provinces and municipalities. Hunan Province has undergone a program to become one of the major citrus producers in China. Poncirus trifoliata is the main rootstock, so citrus viroids are a limiting factor for further citriculture development. In mainland China, only the presence of Citrus exocortis viroid (CEVd) has been reported from Etrog citron indexing, sPAGE (sequential polyacrylamide gel electrophoresis) analysis (2), and reverse transcription (RT)-PCR (3). Three viroid-like RNAs, a1, b1, and d, based on sPAGE patterns were detected years ago in our laboratory in budsticks received from Sichuan Province. To identify different viroids and determine their distribution, a survey has been undertaken. Field trees showing stunting, bark scaling and cracking of the rootstock, and poor yield were tested using biological indexing and PCR for the most frequent citrus viroids. Samples from six trees of a local sweet orange variety and three of a Clementine variety introduced from abroad, both grafted on P. trifoliata and showing a variable degree of bark scaling and cracking, were collected near Changsha and in the County of Xin Ning at the end of summer 2006. Small pieces of bark were inserted in stems of young E. citron budwood grafted on rough lemon and maintained in a warm greenhouse (24 to 32°C). Indexing on E. citron showed mild epinasty and leaf roll typical of citrus viroid infections. To identify specific viroids, bark was ground to a fine powder with liquid nitrogen and total RNA was extracted with TRIZOL Reagent (Invitrogen, San Diego, CA) and tested by RT-PCR to detect CEVd, Hop Stunt viroid (HSVd), and Citrus viroid III (CVd-III), as well as to identify the cachexia variants of HSVd. Four primer pairs were used to test the RNA extracts by RT-PCR (1). All samples were infected by HSVd, eight with CVd-III, and six with CEVd. The cachexia variants of HSVd were detected in four of nine samples. Mixed infections were as follows: one sample had CEVd and HSVd, eight had HSVd and CVd-III, and five were infected by the three viroids. A second sampling 3 months after inoculation gave the same amplification patterns. The results show that at least three viroids are present in citrus orchards in Hunan Province. To our knowledge, this is the first report of cachexia variants of HSVd and CVd-III in China. The common occurrence of these viroids supports the need for proper indexing of mother trees and a specific shoot tip grafting program to create healthy budwood sources to provide healthy plants. References: (1) L. Bernard and N. Duran-Vila. Mol. Cell. Probes, 20:105, 2006. (2) L. Han et al. Viroids. CSIRO Publishing, Melbourne, 283, 2003. (3). Q. Hu et al. Acta Bot. Sin. 39:613, 1997.


1990 ◽  
Vol 39 (3) ◽  
pp. 472-476 ◽  
Author(s):  
J. JUÁREZ ◽  
M. I. MOLINS ◽  
L. NAVARRO ◽  
N. DURAN-VILA

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