Open AccessAntioxidant Enzyme Responses Induced by Whiteflies in Tobacco Plants in Defense against Aphids: Catalase May Play a Dominant Role
Author(s) -
Haipeng Zhao,
Xihuan Sun,
Ming Xue,
Xiao Zhang,
Qingliang Li
Publication year - 2016
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0165454
Subject(s) - catalase , aphid , biology , infestation , nymph , superoxide dismutase , peroxidase , myzus persicae , botany , horticulture , antioxidant , point of delivery , enzyme , biochemistry
Background Bemisia tabaci MEAM1 (Middle East-Asia Minor 1) feeding alters antioxidative enzyme activity in some plant species. Infestation of B . tabaci nymphs decreases Myzus persicae performance on systemic, but not local leaves of tobacco plants. However, it is unclear if B . tabaci nymphs induced antioxidant activities contributing to the aphid resistance. Methodology/Principal Findings We investigated the relationship between antioxidants induced by nymphs of B . tabaci feeding on tobacco and aphid resistance. The activities of catalase (CAT), peroxidase (POD), superoxide dismutase (SOD) and the concentration of hydrogen peroxide (H 2 O 2 ) were assayed in tobacco leaves at different feeding times following infestation of B . tabaci nymphs. The infestation altered the activities of CAT and POD, but had no significant effect on SOD activity. The highest CAT activity was observed at 15 d after infestation. This was 98.2% greater than control systemic leaves, but 32.6% lower than the control in local leaves. Higher POD activity was recorded in local vs. systemic leaves after 15 d of infestation. POD activity was 71.0% and 112.9% higher in local and systemic leaves, respectively, than in the controls. The changes of CAT, but not POD or SOD activity were correlated to levels of aphid resistance. H 2 O 2 levels were higher in local than in systemic leaves in contrast to CAT activity. Tobacco curly shoot virus mediated virus-induced gene silencing was employed to determine if CAT activation was involved in the aphid resistance induced by B . tabaci nymphs. B . tabaci induced CAT activity decreased when the Cat1 expression was silenced. The performance assay indicated that Cat1 silencing made B . tabaci infested plants a more suitable host for aphids than infested control plants. The aphid survival rate was reduced by 40.4% in infested control plants, but reduced by only 26.1% in Cat1 -silenced plants compared to uninfested controls. Also, qPCR results showed that silencing of Cat1 led to the suppression of the B . tabaci mediated PR-2a expression. Conclusions/Significance Aphid resistance in plants infested with B . tabaci nymphs is associated with enhanced antioxidant activities in which CAT may play a dominant role. This resistance probably acted via interactions with SA-mediated defense responses.