Partial antibiosis to Rhopalosiphum padi in wheat and some phytochemical correlations

Abstract

The fecundity of the aphid Rhopalosiphum padi during the first ten days of reproduction was measured on five wheats at three growth stages. The wheats were of UK and Iranian origin, but also involved both spring and winter wheats as well as hexaploid and tetraploid types. Aphids which had already been reared on the respective variety for at least one generation were transferred to the experimental plants. The tetraploid Emmer showed some resistance in comparison with the hexaploid UK varieties at later growth stages, whereas the Iranian variety Moghan 2 appeared relatively resistant only at the tillering stage. The other Iranian variety, Ommid, was resistant at all growth stages, and appears to be the most resistant hexaploid wheat variety t o R. padi so far identified.Correlations of aphid fecundity with plant chemistry were attempted with total phenolic compounds, hydroxamic acids and amino acids. All three of these chemical groups have previously been reported as correlated with plant resistance to cereal aphids. Even just for the results at the tillering stage, no correlation could be found for phenolics or hydroxamic acids, but a multiple regression based on the levels of alanine, histidine and threonine accounted for over 95% of the variation in aphid fecundity at all 15 data points (5 wheats X 3 growth stages). No cause or effect relationship is necessarily implied.

Constitutive and Induced Differential Accumulation of Amino Acid in Leaves of Susceptible and Resistant Soybean Plants in Response to the Soybean Aphid (Hemiptera: Aphididae)

“…For example, A. fabae performance was positively correlated with the concentration of protein and nonprotein amino acids in Vicia species (Holt and Birch 1984), and the concentration of the 10 essential amino acids were higher in susceptible P. sativum plants than in resistant varieties, with the difference for ASN and ASP being the greatest (Auclair 1976). However, and in contrast with our results, wheat cultivars resistant to Rhopalosiphum padi had high levels of ALA, HIS, and THR (Kazemi and Van Emden 1992), and GLU was negatively associated with R. padi performance (Weibull 1994). In addition, in a cucurbit species (melon, Cucumis melo L.), GLU was higher in the Aphis gossypiiÐresistant line than in the susceptible line (Chen et al 1997).…”

“…The amino acid composition of the phloem has also been related with aphid host plant resistance. Studies in cereal crops including oats, barley, rice, and wheat have shown that speciÞc amino acids are correlated with resistance to aphids (Weibull 1988(Weibull , 1994Kazemi and Van Emden 1992). Studies in legumes like Vicia faba L. (Holt and Birch 1984) and Pisum sativum (Auclair 1976) suggest a potential role for total content of free amino acids and amino acids composition in aphid resistance.…”

DIMBOA levels in hexaploid Brazilian wheat are not associated with antibiosis against the cereal aphids Rhopalosiphum padi and Sitobion avenae

“…For instance, hydroxamic acids showed no correlation with a variable response to R. padi fecundity of five wheat varieties (representing UK and Iranian origin and tetra and hexaploid what) at tillering stage (Kazemi and Emden 1992). Addition-ally, levels of hydroxamic acids in tetra-and hexaploid wheat did not correlate with R. padi settlement and reproduction (Elek et al 2013a).…”

Effects of elevated atmospheric CO2concentrations on phloem sap composition of spring crops and aphid performance

“…While Myzus persicae Sulz. needs Met and g-amino butyric acid (GABA), the amino acids Thr, His and alanine (Ala) are important for Rhopalosiphum padi Koch (Kazemi & Emden 1992).…”