Symptom severity and viral protein or RNA accumulation in lettuce affected by big-vein disease

Abstract

Big-vein disease (BVD) is a widespread and economically damaging disease in lettuce (Lactuca sativa L.). Typical symptoms are chlorotic clearing around leaf veins, leaf deformations, and impaired head development. In this research, we studied the relationship between symptom intensity and protein and viral RNA accumulation in infected plants. Naturally infected lettuce plants, from the field or greenhouse, were classified according to their symptomatology: mild, moderate, severe, and symptomless. Coat protein accumulation was evaluated by a double antibody sandwich/enzyme-linked immunosorbent assay (DAS-ELISA), and RNA levels were studied by semiquantitative reverse transcription polymerase chain reaction (RT-PCR) and quantitative RT-PCR. Virus coat protein accumulation did not differ for the two viruses associated with this disease among lettuce plants showing different symptom severity. Similarly, abundance of Mirafiori lettuce big-vein virus (MLBVV)-RNA3 or Lettuce big-vein associated virus (LBVaV)-RNA-2 were not different (P > 0.05) for diverse big vein disease severity rating scales. This suggests that symptom severity expressed by big-vein diseased lettuce plants did not necessarily reflect the accumulation of viruses associated with this disease in the host. Therefore, lettuce plants showing mild symptoms of BVD do not necessarily present lower virus levels than plants showing more severe symptomatology.

Pathological and Molecular Characterisation of Lettuce Big- Vein Virus and Associated Virus from Egypt

“…The generation of a single PCR amplification product of 233 bp for MLBVVand approximately 360 bpfor LBVaV when RT-PCR technique was applied with a pair of specific primers to the MLBVV and LBVaV investigated here validates the identity of the two viruses. This finding is supported by a similar result previously obtained by Araya et al (2011).…”

“…The Oligonucleotide primer sequence used were: MLBVV sense (5'CAG CAC TTT TTG GAT TTT GTC C'3), MLBVV antisense (5'AGA GAA GCC TGT TCC TGC AA'3), LBVaV sense (5'TCA TCC CCC AGT TCA CAA A'3) and LBVaV antisense (5'ATG TTC TTCGCC ACC TGT CT'3), designed based on sequence of coat protein (CP) gene (Araya et al, 2011). RT and PCR were carried out sequentially in the same tube using QIAGEN One Step RT-PCR Kit in a volume of 25 μl each containing 3 μl of template RNA, 3 μl antisense primer (10uM), 3 μl sense primer (10uM), 1 μldNTPs mix and 5 μl QIAGEN One Step RT-PCR buffer 5x.…”

Diversity of genetic backgrounds modulating the durability of a major resistance gene. Analysis of a core collection of pepper landraces resistant to Potato virus Y

“…No significant correlation was observed between VA and AUDPC ( P = 0.3, Spearman correlation test). This lack of correlation between VA and AUDPC (or plant damage) has been observed previously for different plant–virus interactions (Araya et al ., ; Moury et al ., ; Pagán et al ., ; Sáenz et al ., ), and reveals different levels of tolerance between the 20 pepper accessions. Here, tolerance is defined as the capacity of the host plant to reduce the effect of an increase in VA on the plant fitness or damage (Råberg et al ., ).…”

Identification and characterization of lettuce big vein disease (LBVD) in lettuce (Lactuca sativa) crops in Adana and Mersin provinces in Turkey

“…RT-PCR studies were performed in a two step procedure as described by Araya et al (2011) and Navarro et al (2004) using MiLBVV specific primers (MiLBVV-F-5'-CAG CAC TTT TTG GAT TTT GTC C-3 ' and MiLBVV-R-5'-AGA GAA GCC TGT TCC TGC AA-3'), which yielded a 233 nucleotide (nt) fragment overlapping with a region of coat protein (CP) located on viral RNA3 and LBVaV specific primers (VP-248-5'-CGC CAG GAT CTT TGA TCC ATC TG-3' and VP-249-5'-TTG CGA CAT GTT CCT CCT CAT CG-3'), which yielded a 296 nucleotide (nt) fragment overlapping with a region of coat protein (CP) located on viral RNA2. Selected isolates of MiLBVV, Yakapınar (2-MiLBVV 1 E10), Yüreğir (4-MiLBVV 1 F10), Yumurtalık (6-MiLBVV 1 G10), Yenice 1 (11-MiLBVV 2 H10) and Yenice 2 (12-MiLBVV 2 E11) and isolate of LBVaV, Yüreğir (4-VP 248 A12) were used in molecular studies.…”

“…Due to the disease, chlorotic opening of the leaf veins in infected lettuce plants causes symptoms such as leaf deformation, delay in maturation, and decrease in head size or no head formation. The overall quality and yield of the product are affected (Araya et al 2011). Lettuce big-vein associated virus (LBVaV, genus Varicosavirus) is a rod-shaped virus transmitted by Olpidium brassicae was thought to be causal agent of LBVD, historically, but recently the Mirafiori lettuce big-vein virus (MiLBVV) was detected to be causal agent of the big vein symptom in lettuce plants.…”