Loss of Function of FATTY ACID DESATURASE7 in Tomato Enhances Basal Aphid Resistance in a Salicylate-Dependent Manner

• Published in: Plant physiology (Bethesda) Vol. 158; no. 4; pp. 2028 - 2041
• Main Authors: Avila, Carlos A., Arévalo-Soliz, Lirio M., Jia, Lingling, Navarre, Duroy A., Chen, Zhaorigetu, Howe, Gregg A., Meng, Qing-Wei, Smith, Jonathon E., Goggin, Fiona L.
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Biologists 01-04-2012
• Subjects: Acetates - pharmacology; Animals; Aphids - physiology; Arabidopsis - drug effects; Arabidopsis - enzymology; Arabidopsis - immunology; Arabidopsis - parasitology; Biological and medical sciences; Biosynthetic Pathways - drug effects; Cyclopentanes - metabolism; Cyclopentanes - pharmacology; Disease Resistance - drug effects; Fatty Acid Desaturases - metabolism; Fatty acids; Fecundity; Feeding Behavior - drug effects; Fertility - drug effects; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Plant - drug effects; Genes, Plant - genetics; Genetic mutation; Genotypes; Inoculation; Insect genetics; Lycopersicon esculentum - enzymology; Lycopersicon esculentum - genetics; Lycopersicon esculentum - immunology; Lycopersicon esculentum - parasitology; Mutation - genetics; Oxylipins - metabolism; Oxylipins - pharmacology; Plant cells; Plant Diseases - immunology; Plant Diseases - parasitology; Plant physiology and development; Plant Proteins - genetics; Plant Proteins - metabolism; Plants; PLANTS INTERACTING WITH OTHER ORGANISMS; Polymerase chain reaction; Population growth; Salicylic Acid - metabolism; Salicylic Acid - pharmacology; Survival Analysis; Transgenes - genetics; Up-Regulation - drug effects; Up-Regulation - genetics; Aphidoidea; Insecta; Tomato; Fatty acids; Resistance; Homoptera; Vegetable crop; Plant physiology; Arthropoda; Dicotyledones; Angiospermae; Lycopersicon esculentum; Spermatophyta; Solanaceae; Salicylates; Invertebrata
• ISSN: 0032-0889; 1532-2548; 1532-2548
• DOI: 10.1104/pp.111.191262

We report here that disruption of function of the ω-3 FATTY ACID DESATURASE7 (FAD7) enhances plant defenses against aphids. The suppressor of prosystemin-mediated responses! (sprl) mutation in tomato (Solatium lycopersicum), which eliminates function of FAD7, reduces the settling behavior, survival, and fecundity of the potato aphid (Macrosiphum euphorbiae). Likewise, the antisense suppression of LeFAD7 expression in wild-type tomato plants reduces aphid infestations. Aphid resistance in the sprl mutant is associated with enhanced levels of salicylic acid (SA) and mRNA encoding the pathogenesis-related protein P4. Introduction of the Naphthalene/salicylate hydroxylase transgene, which suppresses SA accumulation, restores wild-type levels aphid susceptibility to sprl. Resistance in sprl is also lost when we utilize virus-induced gene silencing to suppress the expression of NONEXPRESSOR OF PATHOGENESIS-RELATED PROTEINS1 (NPR1), a positive regulator of many SA-dependent defenses. These results indicate that FAD7 suppresses defenses against aphids that are mediated through SA and NPR1. Although loss of function of FAD7 also inhibits the synthesis of jasmonate (JA), the effects of this desaturase on aphid resistance are not dependent on JA; other mutants impaired in JA synthesis (acx1) or perception (jail-1) show wild-type levels of aphid susceptibility, and sprl retains aphid resistance when treated with methyl jasmonate. Thus, FAD7 may influence JA-dependent defenses against chewing insects and SA-dependent defenses against aphids through independent effects on JA synthesis and SA signaling. The Arabidopsis (Arabidopsis thaliana) mutants Atfad7-2 and Atfad7-1fad8 also show enhanced resistance to the green peach aphid (Myzus persicae) compared with wild-type controls, indicating that FAD7 influences plantaphid interactions in at least two plant families.