Crop and Non-Crop Plants as Potential Reservoir Hosts of Alfalfa mosaic virus and Cucumber mosaic virus for Spread to Commercial Snap Bean

Abstract

Mueller, E. E.. Groves, R. L., and Gratton, C. 2012. Crop and non-crop plants as potential reservoir hosts of Alfalfa tnosaic virus and Cucttmber mosaic virus for spread to commercial snap bean. Plant Dis. 96:506-514.Diseases caused by aphid-transmitted viruses such as Alfalfa mosaic virus (AMV) and Cttcumber tnosaic virus (CMV) have increased in snap bean {Phaseolus vulgaris) in the Midwestern United States. Plants immediately surrounding agricultural fields may serve as primary virus inocula for aphids to acquire and transmit to bean crops. Tbc project objectives were to (i) identify potentially important AMV and CMV reservoirs among naturally infected plants and (ii) determine the relationship between the virus inoculum potential (VIP) in adjacent crop field margins and virus incidence in P. vutgaris. From 2006 to 2008. surveys were conducted to quantify the virus incidence and per-centage cover (2008 only) of plants present within 5 m of the P. vutgaris crop. In all. 4.350 individual plants representing 44 species were assayed, with overall AMV and CMV incidences averaging 12 and 1.5%, respectively. A VIP index was developed and used to rank the importance of virus-susceptible plants in adjacent field margins. The overall VIP index for AMV in field margins was weakly associated with AMV incidence in P. vutgaris and no relationship was observed between local CMV inoculum and P. vutgaris incidence, suggesting that factors additional to local inoculum sources may influence CMV epidemics in P. vulgaris. Since the establishment of the soybean apbid Aphis glycines Matsumura (Hemiptera: Aphididae) in 2000, viral diseases have become more prevalent in commercially grown crops in the Midwestern United States. Soybean (Glycine max (L.) Merrill), snap bean (Phaseolus vulgaris L.). potato (Solanum tuberosum L.), and pepper (Cttpsicum anituum L.) are a few examples of cultivated plants wbere increased incidence of apbid-transmitted viruses have been observed and have resulted in significant crop loss (5,29.34.35.40). In Wisconsin, yield reductions in P. vutgaris have been attributed, in part, to the abortion of developing flowers as well as malformed, unmarketable pods caused by infections of nonpersistently transmitted viruses, sucb as Atfalfa mosaic virus (AMV) and Cucumber mosaic virtts (CM\)(\1,T1).As members of the virus family Bromoviridae, AMV and CMV can infect a wide variety of host species. Over 600 plant species are reported to be susceptible to AMV infection, especially plants of the Fabaceae family. AMV generally incites cbaracteristic yellow, bright-green "mosaic" foliar discoloration throughout the leaf surface and, in P. vulgaris, AMV infections are often localized but occasionally produce systemic symptoms such as stunting, yellow spotting on leaves, and pod deformation (22,23.52,53). CMV can infect over 885 plant species, resulting in numerous foliar symptoms, including vein clearing, leaf blistering, and pod distortion in P. vulgaris (38,39). Additional symptoms induced by CMV in P. vulgaris include gre...

A Survey on Plant Viruses in Natural Brassicaceae Communities Using RNA-Seq

“…Figures Fig. 1 Omoidegawa (4) A. halleri Perennial 68 39 18 21 0 56 -62 91% (1) All plants were analyzed by real-time PCR and numbers in brackets indicate the samples analyzed also by RNA-Seq (2) The presence of a novel putative virus, AflV1, was determined only for RNA-Seq-analyzed samples (3) Number of plants infected by any of the six detected viruses (4) Data from , and there were no other Brassicaceae species in Omoide-gawa site [25] Kamitani M*, Nagano AJ, Honjo M, Kudoh H* "A Survey on Plant Viruses in Natural Brassicaceae Communities Using RNA-Seq" Microbial Ecology. *Corresponding author Hiroshi Kudoh: kudoh@ecology.kyoto-u.ac.jp…”

“…The authors declare that they have no conflict of interest. Not annotated 165 314 36 (1) Number of contigs annotated to viruses in reference list and considered to be derived from TuMV, CMV, BrYV, and PZSV (2) Number of contigs annotated to other viruses with moderate similarities and treated as candidates for putative novel viruses (3) BdMoV RNA1 73%…”

“…Further experimental analyses are required to determine whether the strains in natural plantcommunities are infectious to crop plants. Previous studies also reported some evidence of the virus exchange between crops and wild plants, which implies future-emergent viruses in crops can be investigated from viruses in natural habitats[2,42].…”

“…Therefore, the distribution patterns of plant viruses in natural vegetation is likely to be different from those found in agricultural fields, although studies on plant viruses have traditionally targeted to viruses that cause crop diseases. Some earlier studies investigated viruses in wild plants based on the idea that natural vegetation may have served as a reservoir for diseases [1,2]. More recently, increasing number of studies have become investigate plant viruses in natural vegetation aiming to understand their ecology [3][4][5].…”

Host plant resistance promotes a secondary pest population

“…While aphid‐vectored plant viruses are not a major concern in alfalfa, they are in potato (Syller ), soybean (Clark and Perry ), and snap bean (Mueller et al. ). In these crops, potato leafhoppers could lower virus transmission by limiting aphid populations, or increase virus transmission by reducing plant quality and promoting interplant movement by aphids.…”