ABSTRACT
Survival of Bemisia tabaci and activity of plant defense-related enzymes in genotypes of Capsicum annuum L.

Luis Latournerie-Moreno1 , Alex Ic-Caamal1, Esaú Ruiz-Sánchez1*, Horacio Ballina-Gómez1, Ignacio Islas-Flores2 , Wilberth Chan-Cupul3, and Daniel González-Mendoza4
 
The whitefly Bemisia tabaci (Gennadius, 1889) is a major plant pest of horticultural crops from the families Solanaceae, Fabaceae and Cucurbitaceae in Neotropical areas. The exploration of host plant resistance and their biochemical mechanisms offers an excellent alternative to better understand factors affecting the interaction between phytophagous insect and host plant. We evaluated the survival of B. tabaci in landrace genotypes of Capsicum annuum L., and the activity of plant defense-related enzymes (chitinase, polyphenoloxidase, and peroxidase). The landrace genotypes Amaxito, Tabaquero, and Simojovel showed resistance to B. tabaci, as we observed more than 50% nymphal mortality, while in the commercial susceptible genotype Jalapeño mortality of B. tabaci nymphs was not higher than 20%. The activities of plant defense-related enzymes were significantly different among pepper genotypes (P < 0.05). Basal activities of chitinase, polyphenoloxidase and peroxidase were significantly lower or equal in landrace genotypes than that of the commercial genotype Jalapeño. The activity of plant enzymes was differential among pepper genotypes (P < 0.05). For example, the activity of chitinase enzyme generally was higher in non-infested plants with B. tabaci than those infested. Instead polyphenoloxidase (‘Amaxito’ and ‘Simojovel’) and peroxidase enzymes activities (‘Tabaquero’) increased in infested plants (P < 0.05). We conclude that basal activities of plant defense-related enzymes could be act through other mechanism plant induction, since plant defense-related enzymes showed a different induction response to B. tabaci. We underlined the role of polyphenoloxidase as plant defense in the pepper genotype Simojovel related to B. tabaci.
Keywords: Host plant resistance, pepper germplasm, plant defense-related enzymes, whitefly.
1Instituto Tecnológico de Conkal, División de Estudios de Posgrado e Investigación, C.P. 97345, Yucatán, México. *Corresponding author (esau_ruiz@hotmail.com). 2Centro de Investigación Científica de Yucatán, Unidad de Bioquímica y Biología Molecular de Plantas, Mérida, C.P. 97200, Yucatán, México. 3Instituto de Ecología A.C., Red de Diversidad y Sistemática, C.P. 91070, Xalapa, Veracruz, México. 4Universidad Autónoma de Baja California, Instituto de Ciencias Agrícolas, C.P. 21705, Ejido Nuevo León, Baja California, México.