Characterizing the interaction between salt-stressed soybeans, viral infection, and vector performance.
A. G. LANEY (1), K. L. Korth (1). (1) University of Arkansas, Fayetteville, AR, U.S.A.
Crop damage due to salt stress is an increasing problem in agriculture worldwide. Soybean, <i>Glycine max</i>, genotypes differ in their ability to tolerate salt stress. Cultivars that limit the amount of chloride in foliar tissue are more salt tolerant and are called chloride excluders, whereas those that cannot are salt sensitive and termed chloride includers. An excluder, cv. Manokin, and includer, cv. Clark, were subjected to salt stress, <i>Soybean mosaic virus</i> infection, and feeding by <i>Aphis glycines</i> to test the impact of single and multiple stresses on aphid performance and plant responses. Soybeans were mechanically inoculated with SMV and salt stressed by flooding daily after systemic virus symptoms were observed. After 7 days, three third-instar aphids were caged on treated and non-treated plants. After two weeks, aphid populations were counted and static headspace volatiles were analyzed using GC-MS. Untreated plants supported significantly higher aphid populations than salt stressed and/or SMV-infected soybeans. Soybeans that were both salt stressed and infected with SMV had significantly smaller aphid populations than other treatment/virus combinations. Both 3-hexen-1-ol and 1-octen-3-ol were aphid induced but levels altered by salt stress and SMV. For example, both treatments reduced 1-octen-3-ol levels in Manokin. This suggests that the interaction between virus, vector, host and environment could potentially impact the epidemiology of SMV in the field.
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