Movement of barley mild mosaic and barley yellow mosaic viruses in leaves and roots of barley

Abstract

Leaves of barley plants were mechanically inoculated with barley mild mosaic virus (BaMMV) and roots were inoculated using viruliferous zoospores of the fungus vector Polymyxa graminis. At intervals after inoculation, leaves and roots were tested by different methods to detect virus coat protein (ELISA or Western blot) or nucleic acid (slot-blot or reverse transcriptase-PCR) . Following inoculation with zoospores, virus could be detected in roots after 1 wk (Western blot or PCR) but not until 3-4 wk by ELISA. Virus moved to leaves in 5-6 wk but, except at temperatures of about 20°C, plants had to be cut back close to soil level to stimulate virus movement. Following mechanical inoculation, virus could be detected in leaves of a susceptible cultivar within 5 days by ELISA and 3 days by the other methods. Western blots and PCR showed that virus was present in the roots by 5 days. BaMMV was not detected by any method in leaves or roots of a resistant cultivar, indicating that the virus did not multiply in it. When leaves were mechanically inoculated on a small area only, BaMMV capsid protein was detected below the inoculated site at 4 days and in young growing leaves and roots at 13 days after inoculation but never above the inoculation site or in older leaves. After stem extension began, new leaves of infected plants were free of symptoms. The results are compared to observations of plants infected with barley yellow mosaic virus (BaYMV). It is proposed that movement of BaMMV and BaYMV is strongly related to the phloem transport and to the source-sink pattern of winter barley plants.

A two‐step multiplex RT‐PCR method for simultaneous detection of soil‐borne wheat mosaic virus and wheat spindle streak mosaic virus from France

“…Nucleic acid was extracted using the modified procedure of Hall et al . (1978 ), described by Schenk et al . (1995 ).…”

A new furovirus infecting barley in France closely related to the Japanese soil-borne wheat mosaic virus

“…Esterel) 3-4 weeks after mechanical inoculation (Schenk et al, 1995). First-strand cDNAs were reverse transcribed using oligonucleotide primer sb11 corresponding to the 3¢-terminal 16 nucleotides of RNAs 1 and 2 of viruses belonging to the genus Furovirus.…”

35S promoter-driven cDNAs of barley mild mosaic virus RNA1 and RNA2 are infectious on barley plants.

“…For this reason we have focused on a mechanically transmissible French isolate of BaMMV (isolate M), which has now been fully sequenced Jacobi et al, 1995 ;. RNA2 of isolate M contains a deletion of approximately 1 kb in the 3h-terminal region of the P2 gene compared to RNA2 of fungally transmitted (wildtype) virus.…”

“…These proteins are comparable in size and expression level to those found in plants infected with isolate M. In a second test we assessed the presence of RNA1 and RNA2 by means of RT-PCR to amplify RNA1-and RNA2-specific sequences. Total RNA was extracted from leaves as described by Schenk et al (1995). First-strand cDNA was synthesized with pd(T)…”