The resistance of lettuce (Lactuca sativa L.) to Nasonovia ribisnigri: bionomics of N. ribisnigri on near isogenic lettuce lines

Abstract

The intrinsic rate of increase (rm‐values), mean relative growth rates and mortality of Nasonovia ribisnigri (Mosley) (Homoptera, Aphididae) on different lines of lettuce (Lactuca sativa L.) were determined. Near isogenic resistant and susceptible lines, plus their ancestors, were used. Bionomics of N. ribisnigri on the resistant lines (NrNr) with the dominant Nasonovia resistance gene (Nr‐gene) differed clearly from the susceptible lines (nrnr). Mortality was high, no larvae reached adulthood, and no reproduction nor honeydew production was seen on the resistant lines. Transfer of aphids to susceptible plants after a period of 2 days on the resistant lines showed no signs of intoxication of aphids. Apparently there is no feeding on the resistant lines. It is not clear whether the aphids can not reach the phloem or do not accept it on the resistant line.

Mi-Mediated Resistance Against the Potato AphidMacrosiphum euphorbiae(Hemiptera: Aphididae) Limits Sieve Element Ingestion

“…These include resistance in melon (Cucumis melo L.) line AR5 to the cottonÐmelon aphid, Aphis gossypii Glover, and for lettuce (Lactuca sativa L.) carrying the Nr gene conferring resistance to Nasonovia ribisnigri Mosely (van Helden et al 1993, Klingler et al 1998. In contrast, factors outside the phloem sieve element were implicated as mediators of the resistance in sorghum (Sorghum bicolor Moench) against Schizaphis graminum Rondani and in wheat (Triticum aestivum L.) against Rhopalosiphum padi L. In these systems, resistance was related to the time needed by the aphid to reach the phloem, and therefore the presence of a physical or chemical barrier was speculated Campbell 1984, Givovich andNiemeyer 1991).…”

The nematode resistance geneMiof tomato confers resistance against the potato aphid

“…For example, the lettuce gene Nr, for resistance against the aphid Nasonovia ribisnigri, is effective only against one aphid species and, like Mi, results in greatly reduced phloem ingestion (29)(30)(31). In another example, the recently mapped gene Sd1 that confers resistance to the rosy leaf curling aphid Dysaphis devecta in apple is effective against aphids biotypes 1 and 2 but not to a third biotype (32).…”

Categories of Resistance to Greenbug (Homoptera: Aphididae) Biotype I in <B> <I>Aegilops tauschii</I> </B> Germplasm

“…The bluegreen aphid resistance gene, AKR, identified in M. truncatula, also maps to a region containing NBS-LRR class of genes (Klingler et al, 2005). In addition, Nr in lettuce, Sd1 in apple, RAG1 and RAG2 in soybean, and RAP1 in M. truncatula have also been reported in conferring resistance against lettuce aphid, rosy-leaf curling aphid, soybean aphid and pea aphid, respectively (Helden et al, 1993;Roche et al, 1997;Hill et al, 2006;Stewart et al, 2009, Kim et al, 2010. Several loci conferring biotype-specific resistance, including Aph in maize, and Gby and Dn in wheat, have also been reported in providing resistance against corn leaf aphid, greenbug and Russian wheat aphid, respectively (Marais and Du Toit, 1993;Boyko et al, 2004;Castro et al, 2005;So et al, 2010).…”