TY  - SER
AU  - Calatayud, Paul-André
AU  - Rahbé, Y.
AU  - Delobel, B.
AU  - Khuong-Huu, F.
AU  - Tertuliano, M.
AU  - Le Rü, B.
TI  - Influence of secondary compounds in the phloem sap of cassava on expression of antibiosis towards the mealybug Phenacoccus manihoti
KW  - Manihot esculenta
KW  - Pest mites
KW  - Phenacoccus manihoti
KW  - Sap
KW  - Phenolic compounds
KW  - Glycosides
KW  - Cyanides
KW  - Antagonism
KW  - Varieties
KW  - Acaros nocivos
KW  - Savia
KW  - Compuestos fenólicos
KW  - Glicósidos
KW  - Cianuros
KW  - Antagonismo
KW  - Variedades
KW  - Cassava
KW  - Yuca
KW  - Journal articles
KW  - Artículos en revistas
KW  - Plagas de las Plantas
KW  - Pests of plants
KW  - Journal article
N2  - Identification and assay of cyanogenic and phenolic compounds in phloem sap of cassava (Manihot esculenta Crantz, Euphorbiaceae) and in honeydew of the cassava mealybug Phenacoccus manihoti Matt. Ferr. (Homoptera, Pseudococcidae) were realised. Cyanogenic glucosides and three flavonoid glycosides (rutin, kaempferol glycoside-1 and kaempferol glycoside-2) were found to be translocated in cassava phloem sap and consumed by the mealybug. Differences in profiles of secondary compounds of phloem sap and honeydew samples, characterised mainly by the appearance of free cyanide and of a free flavonoid, suggest the metabolic processing of at least some of the ingested compounds. The relationship between foliar concentrations of these different compounds and expression of the antibiotic resistance of cassava towards P. manihoti was also investigated in 7 varieties of cassava and in the 'faux-caoutchouc' hybrid. Intestation by mealybug was followed by a clear increase in levels of both rutin and kaempferol glycoside-2, while no modification in cyanide contents was noted. The best rank correlation between antibiotic resistance (measured by the intrinsic rate of increase rc) and secondary compounds analyzed is observed with rutin contents of infested plants (p=-0.73; p=0.05). The possible implication of this compound in the biochemical mechanisms accompanying cassava defence reaction to mealybug attack is discussed
ER  -