Impact of <I>Diuraphis noxia</I> and <I>Rhopalosiphum padi</I> (Hemiptera: Aphididae) on Primary Physiology of Four Near-Isogenic Wheat Lines

Abstract

The impact of feeding injury by the Russian wheat aphid, Diuraphis noxia (Mordvilko) (Hemiptera: Aphididae), and bird cherry-oat aphid, Rhopalosiphum padi (L.) (Hemiptera: Aphididae) on susceptible and resistant wheat, Triticum aestivum L., near-isogenic lines 'Tugela' (susceptible), Tugela-Dn1 (antibiotic), Tugela-Dn2 (tolerant), and Tugela-Dn5 (antixenotic) was evaluated by assessing photosynthetic parameters. Photosynthesis and closely related parameters, pigment composition, and nonstructural carbohydrates were measured at 1, 3, and 9 d after aphids were introduced on plants maintained under greenhouse conditions. Overall, R. padi had a higher reproductive capacity within a period of 9 d compared with D. noxia on all lines except Tugela-Dn2. Although the visible injury symptoms associated with aphid injury can be highly species specific, the data indicate that photosynthetic reduction is a common physiological pattern of wheat response to aphid feeding, irrespective of chlorosis elicitation. Although both aphids negatively affected net photosynthesis, D. noxia had a greater impact than R. padi, even when aphid numbers were considerably fewer for D. noxia (100-150 aphids per plant) compared with R. padi (> 200 aphids per plant). The photosynthetic pigment and carbohydrate data suggest that the initial net photosynthesis reduction elicited by aphid feeding may not be directly related to the light reaction portion of the photosynthetic pathway via pigment losses. It is also unlikely that source-sink manipulation is the primary cause for the observed short-term inhibition of photosynthesis.

Physiological responses of resistant and susceptible barley, Hordeum vulgare to the Russian wheat aphid, Diurpahis noxia (Mordvilko)

“…Similar to those of Macedo et al (2009), Franzen et al (2007, and Macedo et al (2003), our findings provide further evidence that chlorophyll may not be directly impacted by aphid injury, but rather that the carbon fixation reactions of photosynthesis may be more immediately impacted.…”

“…photosynthetic rates and fluorescence parameters) may help to explain the physiological mechanisms underlying plant resistance. Considerable progress has been made toward identifying the physiological responses of resistant and susceptible wheat to D. noxia (Burd and Elliott 1996;Franzen et al 2007;Haile et al 1999;Heng-Moss et al 2003;Macedo et al 2009), however; only limited information is available on the responses of resistant and susceptible barley to aphid feeding (Burd and Elliott 1996;Miller et al 1994). Research on the physiological responses of resistant and susceptible cereals has focused on several different areas including; chlorophyll and protein content, chlorophyll fluorescence, gas exchange, and molecular pathways.…”

“…The most recent studies on the physiological responses of resistant and susceptible cereal to D. noxia were conducted by Franzen et al (2007) and Macedo et al (2009). Franzen et al (2007) found that resistant wheat plants infested with D. noxia had photosynthetic rates similar to or greater than those of control plants, while susceptible-infested plants showed accelerated declines in photosynthesis.…”

“…Results from this study suggest that resistant plants subjected to D. noxia feeding compensated for aphid injury by altering their senescence pathways, while susceptible plants appeared to have accelerated senescence. Macedo et al (2009) examined the impact of feeding injury by D. noxia and the nonsymptomatic aphid, Rhopalosiphum padi on susceptible and resistant wheat. Photosynthetic measurements indicated that feeding by both D. noxia and R. padi caused reductions in photosynthetic activity and that these initial reductions are likely related to stomatal limitation or CO 2 uptake (Rafi et al 1996 andFranzen et al 2007).…”

Effects of sap-feeding insect herbivores on growth and reproduction of woody plants: a meta-analysis of experimental studies

“…A wealth of studies that do not Wt our selection criteria (e.g. Wood et al 1985;Varn and PfeiVer 1989;Meyer and Whitlow 1992;Flynn et al 2006;Macedo et al 2009) have also demonstrated considerable reductions in photosynthetic rates in response to damage by sap-feeders, with only one study (Retuerto et al 2004) showing an opposite eVect. Thus, the data accumulated so far support the conclusion by Welter (1989) and Nabity et al (2009) that sap-feeders and defoliators generally impose opposite impacts on plant photosynthesis.…”