Abiotic Transmission of Rice yellow mottle virus Through Soil and Contact Between Plants

Abstract

The roles of guttation fluid, irrigation water, contact between plants and transplantation into contaminated soil in the transmission of Rice yellow mottle virus (RYMV) were assessed. RYMV presence and infectivity were tested by Enzyme-Linked Immunosorbent Assay (ELISA) and by inoculation to susceptible rice cultivar BG90-2. The virus was readily detected in guttation fluid collected from infected rice plants. Transmission tests from this fluid led to high disease incidence (86.6%). Irrigation water collected at the base of infected plants growing in pots was less infectious, as inoculations led to disease incidences below 40%. No virus was detected and could be transmitted from field-irrigation water. Up to 44% healthy rice plants whose leaves were in contact with those of infected plants became infected but, no transmission occurred through intertwined roots. Transplantation of rice seedling into virus-contaminated soil also led to plant infection. However, virus survival in the soil decrease rapidly and infectivity was completely lost 14 days after soil contamination. Altogether, these results indicated that high planting densities of rice are likely to favour secondary spread of rice yellow mottle disease. Transplantation of rice seedlings not earlier than 2 weeks after soil preparation should prevent soil transmission of the virus. Although guttation fluid is highly infectious its contribution to virus infectivity in irrigation water is negligible as field-irrigation water was not found to be an infectious source for RYMV.

Plant to Plant Movement

“…Up to 44% healthy rice plants in contact with RYMVinfected plants became infected (Traoré et al, 2008). This virus is also transmitted abiotically by cows, donkeys, and grass rats (Sarra and Peters, 2003), through guttation fluid (Section VII, G), by beetles (Section III, K), and through contaminated soil, but not through roots (Traoré et al, 2008).…”

Diversity of Rice yellow mottle virus in Benin and Togo and Screening for Resistant Accessions

“…RYMV belongs to the Sobemovirus group and is transmitted either mechanically (Bakker 1974;Fauquet and Thouvenel 1977), several insects or various mammals (Traor e et al 2009). Transmission from leaf to leaf, irrigation water next to infected plants, infected soil (Traor e et al 2008), cow dung or soil with insufficiently decomposed affected plant debris (Reckhaus and Andriamasintseheno 1995) has been documented. Transmission from leaf to leaf, irrigation water next to infected plants, infected soil (Traor e et al 2008), cow dung or soil with insufficiently decomposed affected plant debris (Reckhaus and Andriamasintseheno 1995) has been documented.…”

Modes of transmission and stability of Rice yellow mottle virus

“…Appropriate management of ratoons that can cause soil and water contamination in heavily affected fields will be important for RYMV control. Transmission via soil contaminated with RYMV-leaves was shown to be positive by Traoré and Traoré (2008). The results of our soil transmission experiments indicated that roots, ratoons, and debris of RYMV-infected seedlings after harvesting can be a source of RYMV via contact and contamination of soil and water.…”

“…The virus is transmissible by animals, by wind-mediated leaf contact, and by abiotic factors (e.g. irrigation water) (Abo et al 2000;Sarra and Peters 2003;Sarra et al 2004;Traoré and Traoré 2008). Infection via farm equipment has also been confirmed (Sarra 2005).…”

“…Infection via farm equipment has also been confirmed (Sarra 2005). Transmission of RYMV via guttation fluid from rice paddy fields has also been confirmed experimentally (Traoré and Traoré 2008). Fauquet and Thouvenel (1977) examined longevity in vitro (LIV) and found that RYMV can remain viable in crude extract for at least 34 days at 27°C.…”