Virus‐induced differences in the response of oat plants to elevated carbon dioxide

Abstract

Disease is an integral element of agricultural and natural systems, but the roles pathogens play in determining ecosystem response to elevated CO2 have rarely been examined. To investigate whether disease can alter tbe response of plants to CO2, we examined tbe effects of doubled CO2 (==700 ^mol mol"') on Avena sativa infected witb barley yellow dwarf virus (BYDV), a common patbogen of cereals and grasses. Oats infected witb BYDV sbowed a signiHcantly greater biomass response to CO2 enricbment tban did bealtby plants. Root mass of diseased plants increased by 37-60% witb CO2 enricbment, but was largely unaffected in bealtby plants. CO2 enricbment increased midday leaf-level pbotosyntbesis and instantaneous water use efficiency by 34 and 93% in bealtby plants and by 48 and 174% in infected plants. Foliar carbobydrates increased witb botb CO2 enricbment and BYDV infection, but tbe two factors affected individual pools dissimilarly. CO2 enricbment may alter tbe epidemiology of BYDV by increasing tbe persistence of infected plants.

Influence of cucumber mosaic virus infection on the growth response of Portulaca oleracea (purslane) and Stellaria media (chickweed) to nitrogen availability

“…Furthermore, the consequence of resource availability on the epidemiology of a virus has seldom been considered. Differences in growth and fitness between infected and healthy plants of a perennial Asteraceae were shown to vary with irradiance (Funayama, Hikosaka & Yahara, 1997) whereas the size of the virus reservoir represented by barley plants infected with barley yellow dwarf virus was enhanced under CO # enrichment (Malmstrom & Field, 1997).…”

“…Biomass allocation to leaves and roots was lower and higher, respectively, for healthy than infected plants of P. oleracea but not of S. media (Figs 2, 6). Most often, the biomass allocated to leaves is maintained and root fraction is reduced after infection by a virus, or a rust (Paul & Ayres, 1986), and is related to foliar carbohydrate accumulation and photosynthetic inhibition (Matthews, 1991 ;Malmstrom & Field, 1997).…”

Why Is Living Fast Dangerous? Disentangling the Roles of Resistance and Tolerance of Disease

“…In the experiment presented here, variation along the slow-quick continuum was generated partly by using six host species and partly by manipulating the availability of two soil resources. In contrast, the primary impact of B/CYDVs on hosts is disruption of the uptake and distribution of a different resource-carbon from the atmosphere (Jensen and D'Arcy 1995;Malmström and Field 1997). Consequently, experiments that manipulate both B/CYDVs and light availability or the atmospheric concentration of CO 2 might reveal both a greater importance of tolerance and a trade-off between tolerance and resistance (Wise and Abrahamson 2005; but see Rú a et al 2013).…”

“…Barley and cereal yellow dwarf viruses (B/CYDVs) are a group of phloem-limited, aphid-transmitted RNA viruses (family Luteoviridae) that infect hundreds of grass species worldwide (Irwin and Thresh 1990;D'Arcy 1995); the impact of infection fitness varies widely among hosts (e.g., Jensen and D'Arcy 1995;Malmström and Field 1997;Malmström et al 2005;Seabloom et al 2009). These viruses replicate only in hosts, and transmission among hosts occurs only by feeding aphids (Gray and Gildow 2003).…”

“…The virus directly influences carbon acquisition and allocation by damaging phloem, which reduces chlorophyll content and carbohydrate translocation (Jensen and D'Arcy 1995). This decreases carbon acquisition, allocation of carbohydrates to roots, and leaf and root growth, while increasing leaf and root senescence (Jensen and D'Arcy 1995;Malmström and Field 1997).…”